wallaby

My local hot-rod muffler place was straight up with me, and told me that 2 1/4" would bend real nice up & over the rear axle, But the 2 1/2" would get squashed by the bending machine with turns that tight. They said I'd actually get better flow from a "non-squashed" 2 1/4" pipe. I said to heck with that, and bought tailpipes through Summit. They are mandrel bent (no squashing whatsoever), 2 1/2", and fit perfectly. Flowmaster makes 'em. The muffler shop had no problem installing them.

Corvette had the same problem. Chevrolet decided to kinda flatten that back corner of the valve cover. I don't know if you want to do any welding/ polishing on your fancy covers, but it may be easier than changing the rest of the car. I have used the factory chrome corvette-style with a spacer underneath to raise them up past the rockers.

Rob is correct. Engine after-run is a mechanical problem that should be fixed. It is a condition that can cause damage to your engine. If the after-run is severe, or persistent, then shutting it off in gear is only a "Band-Aid", and not the fix.

while the trans is in park or neutral, the idle is rather high. When you put the car in drive, the engine slows down from the drag of the torque converter. Just turn it off while it's in gear, and the drag will help to stop the engine.

I assume that bumper guards are not avail. for the rear because of the strip?

The 71 SS has that pad across the rear bumper, and I am wondering if the bumper guards on the front are included with 71SS, or an option. The reason I ask is because I have guards only on the front.

Hmmm Mine has three relay-looking things attatched high on the firewall near the A/C box. I tried to find the proper name for them, but the schematic in the repair manual fails to show them. The manual does show a TCS relay and a delay relay. I think the large one is a delay relay. There was no description of the part in the text, but from what I could gather from the wiring, it looks like the delay relay keeps your accessories off until the car has started, or at least waits 6-20 seconds while you turn the key.

Thank you

ok, It's been 20 minutes. My mind is racing. How insane would it be to install one of my old stock springs? Is that like a cardinal sin? ,Or does my cam have too much lift to even consider it?

Don, I have been following your discussions with the others here, and have come to respect your advice. However, what you are telling me is bad news. I figure that you are probably right, and I don't want to give you the chance later on to say "I told you so". But that means the darn heads will have to come off again and go in to be set up. Not to mention the cost. I was really hoping for an easy fix. It seems like I am changing head gaskets as often as my oil. (actually, I am). Sheesh. ....my wife is going to freak out. But thank you for the advice.

Yea, and you'd think that they'd be better than stock. I have all my old stock stuff, I wonder if I could use one of those? oh well.. Next I'll have to find out if I can order up just ONE spring.

A beautiful drive today ended with what I thought was a fouled plug. I drove it home on what seemed like LESS than 7 cyls. and started checking things out. I pulled the plugs and found No.s 6 and 7 to be darker than the rest, put in new plugs....same result. Then substitute cap & wires: no change. I thought crap, I have a cam that's gone flat...but I don't hear any loose lifter noise or anything, but I pull the valve cover and there it is clear as day: a broken valve spring. Number 6, exhaust. My engine is New. Rebuilt 10,000mi ago. The heads were off for valve seals about 4,000mi. ago, but the springs are just 10,000mi. old. OK: what causes a valve spring to break? Is there anything I can do to prevent it? I have a Comp Cams XE268H cam, and the matching lifters and springs. Spring #911-16. (Now THERE is an ironic part number!) So maybe it is a fluke thing, and the other springs are fine; can I replace the spring without pulling the head? ( dang thing is pretty close to that A/C box....)

I run autolite. Are we talking about World Products merlin cyl heads? I have them, and the initial build quality was poor. They were still loaded with casting sand, and the valve to stem clearance was tight in some, and excessive in others. I had bought them assembled, and just figured I could bolt them on and go. First day, I was towed home with a bent pushrod, and a broken rocker arm. I got that fixed, but soon after I began to burn LOTS of oil. The car would put out a thick cloud of smoke while I waited for a stoplight. I was too embarassed to run it that way, so I tore it down for new valve seals. ( the heads came with umbrella seals....not too good). The guides had to be honed to size, then diamond knurled, and teflon positive valve seals installed. The machinist said this is a common problem with World Products heads because their quality control is not good. He also said the cylinder heads make good power, but it is best to buy the heads bare, and have someone reputable assemble them.

By the way, I have the same heads on mine and had some bad experience with them. I have it sorted out now, but did it all the hard way.

Agreed. There was a period when specs called for gaps as large as .060 with HEI systems, but it was found that the increased amperage required to fire the plug was destroying the cap, rotor, and wires. It was not uncommon for the .060 gap to widen as the plug aged, and the spark found it easier to travel straight down through the rotor, to ground on the distributor shaft. There are still spark plugs listed for these aplications that are " extended gap". The plugs come with a gap of about .060 right from the box, and I was told that it was not a good idea to close them down too much, because the ground electrode gets too bent in the process. Instead, use a different plug that starts with the gap you want.

Holly Smokes! What is involved in taking off the fan? Four fasteners? Whew!

Fact is, when you burn a gallon of gasoline, you get more than a gallon of water in return!

Timing too advanced, idle speed too high, engine temp too hot. The three major causes for after-run. I have owned Chevrolets for years, and I just got in the habit of turning off the engine while it's still in gear.

I have been looking into this same application, and finding ANYTHING that is smaller than 2" has been a dead end for me. I have had trouble finding even a header for Monte Carlo. The parts guys say Chevelle header is different somehow. I don't want to spend an arm and a leg...heck, my iron manifolds work fine; but some extra HP and some extra MPG...that would be nice. Don, do you know of a source?

The Q-jet is notorious for developing leaks from the well plugs. They drill passages durring manufacture, and close them off to the outside with soft metal plugs that tend to lossen over time. The darn things are located under the fuel well portion of the carb, and the baseplate with the throttle butterflies will have to be removed to acces them. They recomend that they be repaired by using epoxy to cover them up. The darn things leak fuel, and even if you shut off the flow with the idle screws, the engine keeps going. Get a rebuild kit, and do the plugs while you're at it.

How do these two heads stack up on a street motor? I have a set of oval port Merlins, and they made a world of difference on mine. My old 71 heads came with small valves, and they couldn't be fitted with larger valves and hardened seats. The cost of repairing my old heads was more than what I paid for the merlins. My target was low speed torque and fuel efficiency, since mine is my everyday driver. I am very happy with the Merlins; my only complaint is that they lack a set of bolt holes near the intake runners that Chevrolet used for my upper AC bracket.

if all else fails, I have a good set of used rocker moldings. Both are in very good shape.

When the rod bolts press in, they slightly disfigure the rod. ( basicly the hole in the rod expands when you force the bolt through it) The rod area around the bolt is now deformed, and makes for an irregular surface for the bearings to rest against. Resizing the rods involves taking a couple of thousanths away from the rod ends where they meet with the rods, Then bolting them to the rods, torqueing them down, and boring/honing them perfectly round again. Bolt tightness can be measured in torque, or by bolt stretch. Stretch measurement is the more accurate method. Either way,the goal is to tighten the fastener enough so that it stretches slightly, so as to hold a constant preload on the parts to be joined. ( same thing with head bolts, lug nuts, etc.) Waveloc bolts are stronger, and resist stretching. In order to get the same stretch from a waveloc bolt, it will need to be tightened further.

I think that when new rod bolts are pressed into the rods, the rods need to be resized.