wearymicrobe said:
OK so onto the good and the bad.
The good a local speed shop has a full on kit for aluminum vortec heads and a intake that they can get me that fits. Bad news is its at least a month out. ~1400$ all in with the manifold and all new gaskets and everything I need. I gave them what I want to do with the car and the gearing and the transmission and they do the leg work to find me exactly what I should buy. Well worth the 50$ they charge for the service and paying a little above summit for the parts.
So onto the bad or more likely the pissed off. When I bought the car it had been "tuned" and gone over. The shop that did it gave the motor a clean bill of health. This is the shop that had it setup for 25% more fuel then needed on the main jets so I knew something was off. So I did less then my normal due diligence because well at least someone looked at it. So while I was in I checked the lash and they are all so tight/loose that you would want to cry.
So I yanked all of the rollers out and all of the push rods and sure enough about 8 or 9 of them have visible bends. There are at least four different brands of push rods in this thing as well. So a friend is dropping off a set of 16 crane push rods from his overflow set for 20$ and I already put the rocker stud in for 2.99$ in parts. Super easy with some dry ice and 100% ETOH to freeze it down and some mild 200f heat in the head from a torch. It was 0.003 oversized so it was a bear to put in but it had a self centering ferrule at the end and I just whacked it with a brass hammer and it went straight in to the factory depth. Let it come to temp and its in there.
So now all I have to do it put it back together and see if it runs right. If I think anything else is out of wack I am pulling the motor next weekend and tearing it all the way down. Have not worked on a lot of small block Chevy's before but so far its not so bad. If it could run decently being that out of spec I wonder what it will do when its actually put back together right.
Also I check TDC and thats off by about 2 degrees on the markings so that explains why when it ran much better when I put another 4 of advance in it.
Chevy stuff is cheap and fun so not kicking myself to hard.
My two cents:
Unless you absolutely MUST shave precious pounds off your engine, skip the aluminum. Aluminum is not a performance choice, it's a weight choice. All things being equal, an aluminum head makes less power than an iron head. People used to say that you can run more compression with aluminum, but in actuality, you have to run more compression to maintain your power levels when switching to aluminum. The increased heat conductivity of aluminum saps away more heat from the combustion chamber than iron.
The real money in my opinion is to just get iron Vortec heads. You can find a used set for $250-350, but you'll want to invest the $45 in magnafluxing before you plop down your money. Vortec heads (I'm talking about ONLY the 906 and 062 castings from 350s 96-98) are not nearly as crack-prone as the intarwebs would have you believe, but they are more prone to cracking than something from the 70s. Be aware... factory Vortecs will not tolerate more than about .470" valve lift. This is an easy fix if you get a spring/retainer kit that allows for up to .550". Any more lift and you'll need to measure and possibly cut down the guides.
If you are willing to plop down $1400 on aluminum heads, you are money (and power) ahead to buy the Summit Vortec iron castings. They are about $350 each, and they are basically copies of GM's casting, but they have three things going for them: A) they're new so they have a lot longer time before they would crack, B) they are made from a different alloy that is far less likely to crack, and C) IIRC, they are already equipped with guides or retainers that allow the extra lift.
For a Vortec intake, call up any boat junkyard in the country and find a carb intake from a Vortec I/O. All three of the big ones (Volvo, OMC, and Mercruiser) used Vortec heads with carb intakes, and they licensed existing GM intakes for their builds. Volvo, for instance, re-cast their own version of the Vortec ZZ4 intake (a wonderful piece that costs $350 because "specialty"). The only difference is that it is cast with a bronze liner in the water crossover. I forget the casting number but I think it ends with 304 or 340... something like that. That's a long way of saying... Vortec carb intakes are expensive because they're a specialty item in the car world. In the boat world, they are plentiful and usually cheap. I got one once that was $50 and it came with the entire engine, carb to pan with accessories. It was a warranty replacement engine (blown head gasket) that fell off the radar and the shop was going to scrap it. The intake that was on it had the GM casting number, but the mold had been modified to include the Volvo insignia beside it. I used to have a stockpile of those things but I have since either used them all in builds, or sold them for a cute little profit. That was 15 years ago, but I could buy them for $20-50 plus about $15 shipping. Be aware that Vortec heads have slightly higher intake ports which means you need to be aware of hood clearance if its tight right now.
Your current exhaust should be fine, but Vortec heads have ever-so-slightly higher exhaust ports as well. If your downpipe or header collectors are close to the floorpan, be prepared to adjust them.
With this recipe you can get all the advantages of Vortec heads with none of the drawbacks for under $1000 all in easily. You'll need either self-centering rockers or (of you want to keep the Sharps) use hardened pushrods and guide plates.
If you instead decide to fix what you have, just buy one screw-in stud and tap the hole where the pushed-out stud was. It won't last, but it will work in a pinch. In general, I very much dislike pinned press-in studs. First, you're creating a fracture point where you drilled for the roll pin, second, you are inviting bigger damage by preventing small damage. If a stud starts to work itself out, it's progressive and you can fix it without anything getting broken. Once you pin it, you're forcing the fact that when something goes, it goes because it broke (as you discovered). IMO, you either have press-in studs (which are remarkably reliable) or screw in. I don't pin studs anymore. Too many failures, and once drilled for pins, they can't really be re-engineered for re-use with any other stud configuration. It's the vasectomy of the Chevy SBC world. It can be reversed, but it costs so much that it's cheaper to have a surrogate dad (buy new heads)
