Take14theroad Posted February 23, 2010 Share Posted February 23, 2010 Hello, I have been restoring a 70 Monte for about two and a half years. I am starting to pick out what i want to do with the rear end and have NO IDEA what I am doing, so I figured this would be a good place to look for some advice. I know to give accurate advice more information is probably needed. I have a 400 that I rebuilt. IT is bored 30 over, has a aluminum edelbrock heads that give it a compression ration of about 11.5:1. The cam is pretty big 262/268 with int- .499 exh- .521 for the lift. I have a beefy TH350 and a stock drive shaft. So, to my quetion. I currently have a 12 bolt with a worn out posi (it works just like an open rear end) and 2.72 gears. I want to put something like 3.73 or 3.53 gears in the rear end. I want to put disc breaks in the back, so that is making me lean toward a whole new rear end. Should I rebuild my 12 bolt or buy a bolt in rear end? Should I go with a Ford 9 inch? Do you have any suggestions of places to shop for bolt in? (randys? Mouser?) Thank you very much! Joe Quote Link to comment Share on other sites More sharing options...
kc8oye Posted February 23, 2010 Share Posted February 23, 2010 Check out the Strange S60 axle.. it's a Dana 60 center section with GM A-body suspension mounts... last I checked, they sell for about $3,000 Quote Link to comment Share on other sites More sharing options...
CrazyDavey Posted February 23, 2010 Share Posted February 23, 2010 Hello, I have been restoring a 70 Monte for about two and a half years. I am starting to pick out what i want to do with the rear end and have NO IDEA what I am doing, so I figured this would be a good place to look for some advice. I know to give accurate advice more information is probably needed. I have a 400 that I rebuilt. IT is bored 30 over, has a aluminum edelbrock heads that give it a compression ration of about 11.5:1. The cam is pretty big 262/268 with int- .499 exh- .521 for the lift. I have a beefy TH350 and a stock drive shaft. So, to my quetion. I currently have a 12 bolt with a worn out posi (it works just like an open rear end) and 2.72 gears. I want to put something like 3.73 or 3.53 gears in the rear end. I want to put disc breaks in the back, so that is making me lean toward a whole new rear end. Should I rebuild my 12 bolt or buy a bolt in rear end? Should I go with a Ford 9 inch? Do you have any suggestions of places to shop for bolt in? (randys? Mouser?) Thank you very much! Joe Joe, just a few questions. First what is the mission of the car? Street only, street/strip/ etc.... What is the duration of the cam at .050 and could you give the lift again, I didn't understand what you posted. Unless you are going to do some serious racing a 9" or Dana is overkill. If you want all new stuff you can get a nice complete 12 bolt with c-clip eliminators, an Eaton limited slip, upgraded axles and 3:42-3:73 gears for around $1800-$2000. If you don't think you need c-clip elims and stronger axles you could do yours with a new Eaton posi and Richmond gears for about $1000 parts and labor. Also 11.5 to 1 is going to be gas challenged. General rule of thumb is to keep the compression below 10.5 for a street application...Davey Quote Link to comment Share on other sites More sharing options...
Take14theroad Posted February 23, 2010 Author Share Posted February 23, 2010 The strange is a little bit more money than I was looking to pay, but reviews of it sound like it is a great product. Thank you very much Kc8oye! I guess this car would be a street/strip. I have not really taken it to the strip because having highway gears in not great for that. I would like to take it once I have it all finished up. I guess I would say it is an overkill street car, but that is what I want out of it. I am sorry, I was not very clear about the cam. It is a lunati with the following specs. Intake at .050 lift- 219 Exhaust at .050 inch- 227 Advertised Duration 262 int./268 exh. Valve Lift(with 1.5 rockers) 0.468 int./0.489 exh. lift - the reason I gave the other numbers is because I am running 1.6:1 roller rockers. Lobe Separation (degrees) 112 I am trying to decided between the rebuild and getting a while new rear end. I know I do not need a new one, that 12 bolt would be really solid for what I need, but was trying to see if it would be worth it for the following reasons: The car is either all original, or modifications that can be swapped back for the stock parts. I feel like it is a waste to take out and rebuild a rear end that is still working (I am not sure of this, does the original rear end carry any value?) The other thing is that a bolt in would come set up for disc brakes. so for a complete rebuild, with posi, axles, labor, and whatever random parts I need would only be 1000-1500? are there new bolt in 12 bolts in that price range? Thank you very much, this is all very helpful! o yea, and with the gas thing, it runs a cool 160 degrees and fine on 87 octane. Joe Quote Link to comment Share on other sites More sharing options...
72MC Posted February 23, 2010 Share Posted February 23, 2010 Joe, my opinion, rebuild your 12 bolt. First, the only advantage a Furd 9"inch has over a 12 bolt is the changeability aspect, period. Secondly, if you want a 3 series set of gears, get a new, correct series eaton carrier for the gears you choose. If the carrier comes preloaded with carbon fiber fricton clutches, DUMP THEM or sell them to someone who thinks they are good pieces. You need to buy the old style carbon steel style clutches. The carbon fiber clutches are ussually in 14 packs where the old style steel clutches are 18 piece packs. Under no circumstances buy the steel clutches that look like a daisy flower/open ended tabs. The tabs do not hold up and you will have clutch pieces lining the inside of your housing. Thirdly, I recommend Randy's Ring and Pinion in Washington state. I also highly recommend Yukon axles and parts to compliment the Eaton carriers. Yukon also carries Eaton style carriers. Also, for pinion or tranny yokes, I recommend Mark Williams Enterprize yokes. IMO, they are superior to Strange or other yokes. By rebuilding you 12 bolt rear housing, you can build a top notch, quality rear that will hold up to alot of abuse. Lastly, if you don't know how to rebuild this yourself, do your homework and find someone that REALLY knows what they are doing. Some joker could ruin quality parts in a short period of time. - Dave PS - what full rear assembly did you find for $1000-1500? That is probably only for the housing and axles. Quote Link to comment Share on other sites More sharing options...
Mike 57 Posted February 23, 2010 Share Posted February 23, 2010 I agree with Dave (72MC) rebuild your current rear. As for disk brakes, I believe some guys are going with a set from late 90's blazers Quote Link to comment Share on other sites More sharing options...
Heckeng Posted February 23, 2010 Share Posted February 23, 2010 For your price range, you might buy a 3-series posi, some gears that you like, some aftermarket axles and put all of that in your current rear end housing. The ford rear ends main advantage in my opinion is that you don't have those stupid c-clips holding the axles in, or NOT holding them in if you have some bad luck! The posi options for the 9" fords suck in my opinion except for the true-trac diff now available. Something else you might do is sell your current rear end, and get a Moser 12 bolt. They combine the best of both worlds. They use the 12 bolt rear that is plenty strong for you and will bolt in nicely. You can get an eaton posi for it which is great. The kicker is that they will put ford style axle ends on the tubes to hold the axles in instead of the c-clips so it is a lot safer and better design. If you want disc brakes on the end, there are a couple guys who have bought some kits off of ebay and had really good luck with them for around $400-$500 if I remember right. Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted February 24, 2010 Share Posted February 24, 2010 the 12 as the other have said is more than sufficient for your needs Quote Link to comment Share on other sites More sharing options...
Mike 57 Posted February 24, 2010 Share Posted February 24, 2010 Strange Engineering now makes a C clip eliminator kit that has tapered bearings, two seals, and they say it is street, strip, and circle track. That could save the cost of ford ends. Strange C clip eliminators Quote Link to comment Share on other sites More sharing options...
Take14theroad Posted February 26, 2010 Author Share Posted February 26, 2010 Thank you guys so much. I guess the Fords that I was looking at did not include the third member, that is why they were so cheap. Now the only thing that I have to find is a local place to rebuild it. Does anybody know places in upstate New York? Should I ask around at the local circle track?? Joe Quote Link to comment Share on other sites More sharing options...
Chevyss Posted February 26, 2010 Share Posted February 26, 2010 My 12 bolt was rebuilt w/3:73 gears. Completely rebuilt w/all new parts except for the housing. $1600.00 and that included the c-clip eliminators. I thought is was a good deal. Auburn posi unit w/richmond gears. Quote Link to comment Share on other sites More sharing options...
kc8oye Posted February 26, 2010 Share Posted February 26, 2010 Generally speaking, if your axle is mostly a street use car, you don't want to use c-clip eliminators.. apparently, they tend to leak a lot or something.. I run a 10 bolt with c-clips so I dunno Quote Link to comment Share on other sites More sharing options...
Ian Posted February 27, 2010 Share Posted February 27, 2010 Thank you guys so much. I guess the Fords that I was looking at did not include the third member, that is why they were so cheap. Now the only thing that I have to find is a local place to rebuild it. Does anybody know places in upstate New York? Should I ask around at the local circle track?? Joe Where in Up State NY? I have a buddy near Albany that would probably know someone that could do it right. Quote Link to comment Share on other sites More sharing options...
Clever Idiot Posted February 28, 2010 Share Posted February 28, 2010 Just for my two cents, it looks like a Strange S60 runs about $700 cheaper than a comperable Moser 12-bolt. Strange Moser Quote Link to comment Share on other sites More sharing options...
Clever Idiot Posted February 28, 2010 Share Posted February 28, 2010 Related to this, I'm tearing my Monte apart (obviously), and have done more window shopping than I care to admit. I'm torn between what would be what I think might be the 'best', and just getting the damn thing back on the road. The best = $$$ = even more delay. Engine and trans are gone (or will be tomorrow), and I know exactly what I plan on replacing them with when it comes time. A Year One crate engine Part # CT350PC1 (350 rated at 400+hp/400+ft-lbs) and a 700-R4. I don't plan on racing regularly - I *might* take it to the drag strip once to see what it can do. It's going to be a cruiser/weekend blaster, so it's not going to get a lot of (or any) abuse. My stock rearend is the standard non-posi 10-bolt, don't know the gears. I was thinking of going with a 12-bolt posi or a Strange unit... but now I'm tired of looking at a pile of parts and want to turn it into a car again without blowing money I don't really need to. What can a 10-bolt withstand? Will I end up with shrapnel if I put the stocker unit behind that engine/trans combo? Eventually I'll go to a posi unit and steeper gears, but I'd like to know if that's money I can spend *after* I get it on the road. And I'm wondering now if a 10-bolt will handle that power in a non-abuse situation. I think new axles, posi diff, and gears would be a boatload cheaper than a 12-bolt assembly (kind of like I think rain is wet). And money saved is less time to putting rubber down. Quote Link to comment Share on other sites More sharing options...
Heckeng Posted February 28, 2010 Share Posted February 28, 2010 the 10 bolt will be fine. They are very strong. You can get a posi and gears later on. BUT if you plan on upgrading the engine and plan on drag racing later on, it sure wouldn't hurt having a 12 bolt. Quote Link to comment Share on other sites More sharing options...
Clever Idiot Posted February 28, 2010 Share Posted February 28, 2010 Ok, dove into the rear and got some more info. Definitely 10-bolt. The ring gear bolt heads fit a 3/4" wrench, which confuses me. According to what I could find about identifiying 8.2" vs 8.5", neither one has bolts that big. The 11/16" wrench was too small to get on the bolt heads, which is what that link is saying the 8.5" 10-bolts used. Huh? The bolt heads weren't all gunked up, either, so I don't think build-up might have caused the bigger wrench fit. Also, I found 39-14 stamped on the ring gear, so if those numbers are what I think they are (ring gear tooth count-pinion gear tooth count) then I have 2.78 gears in there. That also confuses me b/c I thought the different possibilities were 2.56, 2.73, 3.07, etc but no 2.78. Just to make sure I'm not completely off here, I spun the passenger axle one way and observed the driver axle spinning the opposite direction. That *does* mean non-posi, right?? Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted February 28, 2010 Share Posted February 28, 2010 your axle could be a BOP (buick,olds, pontiac) yes some got installed in our montes by the sounds of it, it's not a posi, pull the cover to be sure Quote Link to comment Share on other sites More sharing options...
Clever Idiot Posted February 28, 2010 Share Posted February 28, 2010 Pulled the cover, that's how I got the ring gear bolt head size and the tooth count - but I don't know what I'm looking at Doesn't look like any posi units I've seen pictures of online, though. Quote Link to comment Share on other sites More sharing options...
Clever Idiot Posted February 28, 2010 Share Posted February 28, 2010 Yay, more surfing (wife's at work and I'm bored, can you tell? ) You're right, Sam, it's a BOP with an 8.2" ring gear, judging by this picture on Car Craft compared to mine. Quote Link to comment Share on other sites More sharing options...
Heckeng Posted February 28, 2010 Share Posted February 28, 2010 I believe those are supposed to be a little bit better than the Chevy 8.2 aren't they? I think they use larger bearings in some places. Quote Link to comment Share on other sites More sharing options...
Take14theroad Posted March 1, 2010 Author Share Posted March 1, 2010 That is perfect! I live about 20 minutes north of Albany. If you could ask your friend, that would be a huge help. Thank you Joe Quote Link to comment Share on other sites More sharing options...
Winston Wolf Posted March 17, 2010 Share Posted March 17, 2010 I would find a junkyard or swapmeet 12 bolt rear end for an A body GM, doesn't need to be posi, take it apart yourself. Gears 175$ Bearing/install kit 123$ Moroso or Eaton differential 450-550$ You're looking at under a grand to do the whole thing. You can do it yourself, it's not as hard as people make it out to be. You need a dial indicator to check the backlash, and the rest is common tools. Take your time and check all everything. I have personally had bad luck with the Auburn rear ends, they just didn't seem to hold up. I run a Moroso in my car now, and it has worked perfectly and remained tight for many years now. Quote Link to comment Share on other sites More sharing options...
680HPStroker Posted March 25, 2010 Share Posted March 25, 2010 What Dave and Scott said in their initial post. NO C-CLIPS ELIMINATORS for a street car. Weld on bearing housing ends are the only way to go. Quote Link to comment Share on other sites More sharing options...
Guest SSwolf Posted April 3, 2010 Share Posted April 3, 2010 I believe it depends on the use. If it is a regular driver rebuilding the 12 bolt would work fine. If you want to go for overkill for a beast of an engine or for testosterone perposes look at the strange S60 as originally posted. I rebuilt mine and it works great. But if I was to start over I would get the S60 with brakes, gears and all and just bolt it in. But I like overkill. Quote Link to comment Share on other sites More sharing options...
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