LS65Speed

Not sure about the faster motor theory mentioned above but there was a thread that talked about the availability of a DIFFERENT fan for A/C cars versus non A/C cars. I need to check my parts manual again but it seems to me I looked for different part numbers for the A/C versus Non A/C fans. I think my manual showed one number for the fan for both applications. Going to look again and report back when I get home. I spoke to a guy who redid his underhood hardware to accept a larger fan, larger depth NOT larger diameter. He claimed it worked very well, great improvement in his seat of the pants perception of the perf of the system. That said the mods to the housing required fiberglass and sheet metal mods that did not visually appeal to my eye. If it worked it was not visually appealing to my eye. I also would like a stronger air flow...be it from a faster motor (if that would work) or from a stronger fan. Todays A/C equipped cars can blow you right out of the seat with the fan on high. That makes you experience the cool air differently than when the air is moving slowly. Try setting the fan on low and drive along on a hot day. Then push the fan speed up to max. I will "seem" that the A/D is working better but in reality the A/C (from a refrigerator perspective) is working just as it was before you changed the fan speed. The by pass door tip is a very good one. Depending on the position of that door you will see differences in the flow of cool air. I recommend checking the door by taking off the A/C distribution "manifold" that is just behind the radio. Two screws remove that plastic duct from the heater core mounting box. Once you do that it is easy to see what that door is doing. If it is partially closed, or partially open depending on how you look at it, you are giving away air flow that you certainly want in a max A/C situation.

"To my knowledge it was commonly done the other way around. Oval port intake on a rectangular port head to build velocity and increase the low end since the rectangular port heads were so big. Going the other way around will work, but the main issue that has been seen is the step from the rectangular port intake to the oval port head since the intake port is bigger then the head port it will cause turbulence in the air flow coming in unlike when you do it the other way around." You are mistaken...off by a country mile. At least in terms of using Chevy intakes you are off by that country mile. Some aftermarket oval manifolds reportedly were cast in such a way that there was sufficient material on the oval manifold to cover the "roof" of the rectangle head port. The Chevy oval port intake manifold port is so small and the rectangle port is so large that there is no way to seal the point where the manifold meets the head. In the case of both the rectangle port head and the oval port head the bolt patters are the same. This is why the bolt together aspect of this swap works. With a Chevy Oval intake on a rectangle head you would have a HUGE vac leak OR nothing but gasket material to cover the huge upper opening at the top of the rectangle head port roof. Get a pair of rectangle port intake gaskets and a pair of oval port gaskets, line up the holes and look at the gap you will have. The rectangle intake works on an oval head because the rectangle gasket has head material to seat on. The oval Chevy manifold on a rectangle head has no such material...sealing the runner is impossible. The oval (Chevy) intake cannot use either the oval gasket or the rectangle gasket if used on a rect port head. Maybe with the aftermarket manifolds cast for such a conversion...maybe it works, but with Chevy parts....you just can't get a seal between oval manifolds and rectangle port heads. Another point on this velocity discussion. I did not study much fluid dynamics in Engineering School but it seems to me that the following analogy holds true. In long run HVAC ducting it is common to start with a large size duct and neck down the duct cross-section as you get farther and farther from the source of heated or cooled air. This necked down duct cross section change is to increase velocity at the extremities of the ducting. Any velocity gained upstream of the oval port manifold openings would be lost immediately once the air flow encountered the increase in port cross section that accompanied its entry into the rectangle head. Air flow would fall flat on its face and the engine would in effect be right back there with rectangle port velocity numbers. With the exception of the aftermarket oval intake manifold mentioned earlier I doubt this oval on rectangle head combination would even run. As to the increased velocity....I would have to dig out some books from way way back when I was in school but I think the velocity increase theory is just that a theory. I am not saying that people did not try it and believe it worked. If I had more time I would research this theory which for now is firmly in the urban legend category for me. Attached is a pic of a Chevy aluminum 3x2 oval intake up against a rectangle port Chevy intake gasket. As I hope you can see there is no way that combination is gonna seal. It won't work the way it is in the Pic and it won't seal if you try an oval gasket & oval manifold on the rect head.

Most likely because you have a Rectangle Port intake and you don't have an oval port intake. Just kidding Just kidding. People do it all the time, back in the day it was done for the visuals of having an aluminum high riser and a Holley on an engine with otherwise milder internals that should have run a Q-Jet. As to performance gains...I have no idea, in fact I doubt there are gains. I am reasonably sure based on my research that there is nothing to be lost on the street with such a combo. I have researched this with a great many folks who have actually done it and have been assured that it works fine. My LS6 454 is now bolted together with Edelbrock Oval heads and a 67 Vette 435 HP (Rectangle Port ) 3x2 intake. I have yet to drive it set up this way and I do have a 67 oval port 3x2 GM intake on the shelf just in case. There will now likely be no end of discussion and point counter point about this. Folks who have done it will swear it works, folks who likely never have tried it will have all sorts of reasons that it won't work. The word that will come up more and more if this discussion takes off is "reversion". I am just not going to get too deep in this discussion of the pros and cons. Soon I will have my car on the road and I will know one way or the other if it works or not. If it doesn't on goes the oval port 3x2 and the rectangle port 3x2 gets sold. If the rectangle port intake on oval port heads works well the oval port 3x2 gets sold. We will see what we will see.

I don't know what more to say. I don't have pics of the car with the GM aluminum L-78 / L-88 Hi Riser and the GM drop base with the chrome top. JUST GET THE OPEN ELEMENT DROP BASE HIGH PERFORMANCE GM Air Filter and stock height element set up for the aluminum hi rise intake and you are ready to roll. Forget the cowl induction stuff above the carb, it won't work w/o a cowl hood and you don't have one. There is no confusion here on the 4BBL. I can't explain this any better than I have. It is a no brainer with the parts I have outlined. You say you want the Hi Performance look. Get the open element filter element and the drop base and the chrome top (if you go 4BBL) and you can move on to whatever is next in your build.

Didn't I just say that as long as you run a stock GM air cleaner with a drop base you are gonna be OK? Hole in the hood??????? Just decide on a manifold and get the appropriate air cleaner and element and you are done. There is no need for a hole in the hood. The drop base, open element chrome top GM air filer with a stock height (3 inch +/-) paper air filter is going to clear with room to spare on the 4 BBL setup if you chose a 4 BBL. The stock 3x2 foam air filter element, chrome top and base are going to clear and there might be room for additional height above the height of the stock foam 3x2 element. You are making this WAY more difficult than it has to be.

Aaron Let me try to clarify what I have already said in a couple of posts. The high rise Chevrolet aluminum manifold delivered from Chevrolet on the L-78 and L-88 (and some 402 and 396 engines) clears the hood on a Monte Carlo if you use the drop top GM air cleaner base. I ran my car with this setup before I went to the 3x2. No issues. The low rise Chevy4 bbl aluminum intake used on some LS6 Chevelles (used on the cowl induction LS6 cars I THINK ) and some of the last BB solid lifter Corvettes clears the Monte Carlo hood better than the high rise Chevy manifold because it is considerably lower. Because you have asked about my GM 400 HP 67 Corvette 3x2 oval port intake. It is not for sale. It will clear the Monte Carlo hood when the stock GM 3x2 air cleaner element and base is used. The GM aluminum 67 Vette 3x2 435 HP intake will clear the Monte Carlo hood. I have attached pictures of this installation to another post. As I hope you can see...the 3x2 clears the hood with the 3x2 GM stock height air filter element and air filter base. In point of fact there MIGHT be room for a taller air filter element in the GM air cleaner base. K&N will make air cleaner elements to custom heights and I considered having one made that is taller than the stock height GM foam 3x2 air filter element or the stock height K&N washable element that is currently on the car. ALL 3x2 intakes from 68 and 69 will clear the Monte Carlo hood because they are low rise intakes. They are a couple of inches lower than the 3x2 high risers and as I have illustrated the high rise 3x2 manifolds fit just fine. I run a cable bracket from a 68 / 69 3x2 Corvette on my installation. Just order one from any of the Vette parts suppliers and you have that base covered if you go 3x2. The same bracket works for 435 HP and 400 HP intakes. Actually to make it clearer...that bracket fits all 3x2 BB intakes ever made by GM. I hope this gets all the data straight in your mind. There seem to have been a few posts from you on this topic over a period of time that indicate some confusion on what works and what doesn't. I can see where some confusion comes in when you ask a question about GMintakes and get answers about aftermarket manifolds. You are apparently interested only in GM manifolds as was I. Now to summarize: ALL GM aluminum BBC intake manifolds ever made will clear the Monte Carlo hood. My information is proven thru having done it with all the high rise versions so the low risers are a no brainer. I am only speaking about using stock GM air filters and air cleaner bases on both the 4 BBL and 3x2 systems when I make that statement.

http://www.firstgenmc.com/forums/index.php?/topic/15108-163-l72ls6-i-think-intake-fit-on-our-cars/ See above link. 67 (400 and 435) manifolds are considerably taller than the 68 / 69 units. The 67 435 HP unit fit fine as you can see bey the pics. If the 67 fits the 68 / 69 will have even more room. 67 units are more expensive with the 400 HP unit being the most expensive of all units. If you do it don't necessarily run away from one with cracks, stripped threads, you can save a ton of money on the purchase. In point office more have cracks than do not have cracks. There is a guy named Jerry McNeish who is a welding magician and he can fix ANYTHING and make it look like new. www.z28camaro.com. I have a 400 HP 67 on the shelf that that was nearly junk. He redid it and it is near perfect. I know where the cracks were and I can see evidence of any repair so no one else will see it either. You will spend money repairing it (Jerry does not work for free) but the work he returns is show quality and readily re-saleable at top dollar if you should want to sell later.

Doug Do you have any details like the P/N for the fan? Can I assume that the same elections (alt) support the new fans? I have the CS130 and it works fine with my Mark VIII fan. Wondering what you are running for an alternator. Have you checked the start-up draw of those fans from the 150? Ray

John Looked at your profile and your pics. The cars are almost TWINS!!!! When looked at from the outside they are the same triple black with Rally wheels. Different mechanicals but thy would look good parked side by side! Ray

Ok maybe we can work something out for the ned Summit show? Any thoughts on a source for a d-shaft?

John Went out and measured it with it still in the car. 54 Inches. Chevelle shaft? Maybe. Hmmmm? I wonder what the effect of this is on driveline vibes? The car doesn't shake or shudder violently but there are some harmonics at certain speeds. I considered balancing that shaft some time ago but now I am glad I looked into the length issue before I spent money. The yoke in there now extends 3 inches out of the trans before the flange for the U-Joint flares out. Ya wonder how people get the combinations of parts they get. This setup works, I have driven the car several thousand miles but I am not one to beat on my machinery so I guess it will work the way it is at least in normal use. I think this is another thing to add to the list, find a 56 inch tube. I am thinking that short yoke I have on the shelf with the 56 inch shaft is the right way to do this. Anyone have a 56 inch tube anywhere? See what I mean about finding parts? There is a big yard south of Charlotte that allows you to walk and find parts. Not sure if you can remove stuff yourself but they do allow you to walk around from what I have heard. Might need to research who they are and plan a trip.

Maybe one of those shows at Summit? We will see. Honey Do list got in the way of measuring the drive shaft on Thursday. Honey Do got in the way of doing anything BUT the Honey Do list now that I look back at Thursday. I was beat by the time we finished dinner and not about to take the D-shat out. Going to get the numbers on that length today and report back later. Ray

Thank you John !!!! I am in Roswell GA, we should meet some time! I have some parts to sell and I am always looking for parts like the 4 Speed driveshaft. I will measure tomorrow and report back. Can you help me find some sources like a 3.08 12 bolt and some of this miscellaneous small items that are hard to find? M.C. specific parts are getting harder and harder to find so I am always looking for folks in this "section" of the car hobby.

For Murphy Interesting PIC I have two cars so I will try to keep this clear. One car is a 1972. I have had the car since early 1973 and it never had that balancer on the shaft. It was originally a 350 CI TH350 car. I have seen those balancers on GM products but it seems to me they were on the "land yacht" models like the big station wagons and possibly Caddies / Pontiac "B" body. Never saw that balancer on a Chevelle or an MC. For Sam I think it is too short because the U-Joint in the front Yoke is a fair distance back from the trans. Before we get carried away some background you need. The car has a Richmond 5 Speed which is exactly the same bell housing to tail shaft length as a Muncie. I say exactly meaning to within small fractions of an inch. It is not dead nuts EXACT but it is VERY VERY close. I said Muncie earlier to avoid a bunch of discussion about "maybe it is the Richmond..........." from folks who are unaware of the lengths of a Richmond and a Muncie. Now having said that and made my confession. The Richmond uses a TH 400 yoke and the TH400 yoke comes in at least three lengths. One is quite long, visibly longer than the other two versions even when viewed from "all the way across the room". That long yoke is in the Richmond now and it extends a fair distance down the splines on the output shaft. I once compared to to a short TH 400 yoke as far as penetration into the tail housing. It goes plenty deep enough even considering the fact that I think the drive shaft itself is too short. The extra length of that long yoke allows the short drive shaft to work but the penalty for all this is that there is a gap between the end of the tail housing and the drive shaft. This is what makes me think the shaft in this car is of another origin other than being from a Muncie equipped M.C. The front universal joint is a fair distance back from what I have seen on factory cars (stick or automatic equipped) . I am wondering if that yoke and the u-Joint spinning around about a inch further behind the tail housing than normal might induce vibration. Remember the splines of that long yoke extend plenty far into the tail housing. I have already checked that. This is why I need your center to center distance of a known 4 Speed drive shaft to determine if the drive shaft in my car is too short. If it is to short I will get a longer shaft (proper length for a Muncie equipped M.C.) and use a shorter yoke. I have a short one right here in my storage area. First however I need to know the length of a stock 4 Speed shaft. The drive shaft in the car now works. It might be vibrating a bit but that might just be a need for a rebalance OR it might be because that U-Joint is a further distance back from the tail housing than normal. If the drive shaft in the car is indeed too short I will find and rebalance a correct length shaft rather than fool with the shaft that is in the car now. Hope this is not too long and boring and I certainly hope it clarifies why I am digging into this issue.

YES YES YES! That is exactly what I need. I think the shaft in this car is TOO short. I see in your profile that you work in aviation support work. I used to work as a propulsion test engineer at PWA. Moved on to other things later on but never lost my interest in things that fly. Thanks again!

That would be great...is the car a stick or an automatic?

Hello All I am working on a 4 Speed equipped M.C. and am wondering if someone here can answer a couple of questions? #1 What is the length of a drive shaft for a Muncie equipped M.C. when measured from U-Joint center Line to U Joint centerline? #2 Are the Th400 shafts and Th350 shafts from Monte Carlos the same length as the Muncie shafts from Monte Carlos? #3 Are M.C driveshafts (particularly the Muncie equipped M.C. ) shafts different length(s) than the Muncie equipped Chevelle shafts? Thanks for the help!

Your pan appears slightly deeper than mine. Mine measures 7 & 3/4 inches from the pan rail to the lowest point on the front of the sump. Mine appears to be very slightly shorter than the lowest point of the C-member. I will take some pictures ...not sure how they will come out given the lighting. Stand by.

"Again not that I stay awake nights over this but I am thinking that the MC crossmember might be farther forward from the firewall than it is in the Chevelle" As mentioned earlier the engine firewall positioning must be the same. Many folks think that all the added MC length is in front of the C-member. Likely that conclusion is due to the length of the hood and the space between the engine and the radiator.

I can agree that some of the aftermarket pans are OK but I sure hear more crying about them than I hear about stock parts. I guess if one goes to the real high end pans the chances of a problem might be lower. Performance wise..perhaps some folks cross breed things to where they run into trouble, pickup from one vendor, pan from another , tray from someone else. Then throw in headers, kickouts and the results might be upredictable. I might be an "old school" point of view guy and I don't race my cars at all so perhaps the stock stuff is adequate for me. With GM parts I could order a pan, pickup, pump and tray and know the parts would play together. Also as more and more PRC junk shows up I tend to run for the safety of something that has always worked for me. Engine setback...just something I have been curious about not a burning issue by any stretch. Makes sense also but I have run stock Chevelle exhaust pipes on my BBC, everything from (including) the manifold to the tailpipe tips. This seems to indicate that the engine is in the same place relative to the firewall in the MC as it is in the Chevelle. Also my car is a stick and I run all Chevelle parts after the conversion. Again this seems to indicate that the motor is in the same place as the Chevelle. Again not that I stay awake nights over this but I am thinking that the MC crossmember might be farther forward from the firewall than it is in the Chevelle? That seems to be the only way we both can be right about these pans and the partsI have used from Chevelles in my conversion? I know when I had the FI Vette pan on an SB in this car there was plenty of C-member clearance for the front of the sump. BTW..love that pic of your car at the line. Nice to see these "big" cars doing things like that and performing like yours does.

Just for the record..do you know if this Vette pan will fit a Chevelle? I have no idea why they fit the MC because I don't know what if any dimensional differences exist in the MC frame versus the Chevelle frame. There seems to be no end of angst caused by aftermarket pans not fitting / clearing frames. People end up installing then disinstalling aftermarket pans all the time. Chevelles of all years and MC's it is the same story ..."It hits the frame", "it leaks", "I have oil pressure problems at high RPM"...it just goes on and on. Finding a pan that fits 66 67 Chevelles with BB engines seem to be a VERY VERY difficult job if you do not have / want a pan other than "THE" original 4 qt. factory pan. I know I digress a bit here but I think this Vette pan we have is a hidden "jewel", at least for the MC, if you want trouble free installation, extra capacity and a windage tray. Along with all that you get a pan / pump / pickup and tray designed by GM as opposed to some aftermarket Speed Racer goodie designed by folks with who knows what level of skill in automotive engineering. Just MHO here but the aftermarket stuff is stuff I would not touch with a 10 foot pole.

For all the guys stressing about aftermarket oil pans for the Monte Carlo. If you have a BB in your car the OEM GM Corvette BB pan is a bolt in. I have one under the LS6 (Gen IV) in my 1972. The pan has a 5 quart capacity. This translates into a 6 quart oil system capacity assuming a 1 quart filter. I run the factory GM windage tray with GM studs to locate the tray. There is no clearance issue whatsoever, you get extra capacity, you get the windage tray and it is an OEM part which IMHO beats the aftermarket stuff hands down every time. There is ONE and ONLY 1 GM pan for Corvettes equipped with BB engines which were offered from 65 to 73 or 1974 so there should be no issue determine what is what. If it is a BBC OEM GM pan for a CORVETTE it will work. Also for the SBC guys. The FI 327 Corvettes ran a special high capacity oil pan with windage tray and "trap door" baffles that fit the MC chassis also. This pan was offered up until 1965 when the FI engines "went away". Depending on who ya talk to this pan holds 5 or 6 quarts. I run one in a 66 Vette with 6 quarts in the pan plus one additional quart for filling the filter and have no issues. FWIW ...neither my Monte Carlo or my Corvette have headers..IMHO they are just a big PIA but that is another story. Speaking generally about the two pans mentioned above I would suspect no header clearance issues because these pans are the same width in the sump area as a standard SBC or BBC pan. It is not all good news however. Both the SBC and BBC pans I am running are discontinued by GM but you can usually find them thru the usual used parts sources. Considering all the heartburn associated with aftermarket pans these parts might be worth looking for.

I don't post a lot here more a "Lurker" but your comment about "GM Factory Mechanics take pride......." made me post a response. I bought a 454 LS6 crate some years ago, before the "ZZ454" appeared on the scene. I am one of those guys who just doesn't trust anything until the supplier has a track record with me. GM quality has caused some of that general distrust. I took the engine home put it on a stand and took it apart for an inspection. One connecting rod cap was INSTALLED BACKWARDS!!! Anyone here who has built an engine knows you cannot install a rod cap BACKWARDS without POUNDING IT DOWN. They just are not made to fit easily BACKWARDS. GM stepped up with a new rod and ate the machine shop charge to R&R the piston. I took the rest of the motor down to an empty block...checked all dimensions I could check myself and had a shop look over the rest of the block. This was not an oversight. This was just plain sloppy "I could give a S----T work by someone at GM. Just an FYI

Actually I lived in South Glastonbury myself!!!! What shop are you talking about? My house was very near the Glastonbury Hills Country Club...on the east side of town near Rt 2. Yes i did stop by the cruise at Mc D's on Main Street a few times. I worked in the office building just down Glast Blv from McD's. The builing is right on the corner by the on ramp to Rt2 and Rt3!!!! I sure miss the N.E. ...sure winter is a pit up there but there is nothing like the fall. Atl. will be hitting high 80's starting soon and the summenr (for me at least) is just a bad as winter is for some folks up North.

UNIONVILLE CT!!!!!!!!!!!!!!! I grew up in Litchfield and lived in Glastonbury before I moved to Atlanta. The racer I mentioned was from Burlington!!! Wow small world!! Just the other day I read that Marcus Dairy in Danbury folded up. That was a great cruise for Sat nights in the summer. Sad to see it go. I also recall Main Street in Bristol back in the day. That was pretty cool also!!! Do they still have that Sat night cruise on the west side of Bristol?? Out toward Thomaston..just off some large two lane blvd that ran more or less parallel to Rt 6? Yes those are the maniflds I was thinking about. It always seemed a little goofy to me but I suppose the people that make that stuff always needed to have the latest newest "trick" thing to sell more product. Notice that in your picture the mfld has an open plenum.