I am looking at buying a rebuilt 87-95 350 for my ride to rplace my trashed LO3 motor. The 350 motor is a stock rebuilt 350 with a block casting number of 14093638 wich is a 2 bolt main I think. It has the 193 casting number cyl heads. I was told by the shop it has 8.5:1 compression ratio

I Have a set of nearly new World Products 305 S/R torquer cyl heads. Would they be an improvement over the 193's?

Would they raise the compression to high for 87 pump gas?

Or should I sell the Torquers and look for a different set of 350 heads?

 

Yes. Almost anything would, as long as it isn't 70s smoggers like 882s.

That depends on what the motor was "rebuilt" out of. If the pistons are true flat tops with a zero deck height, then the CR would definitely be too high. On the other hand, if it's a typical "rebuilt" motor, then it has cheap cast pistons with an extra .025" of deck clearance on top of the stock .025" or so, which is all still there because the block wasn't decked to the pistons like it would be in a performance build as opposed to a "rebuild"; and about 18cc dishes. That combo - .050" deck clearance, a typical .039" head gasket such as a FelPro, 18cc dish pistons, and 58cc heads - will give you an actual CR of about 8.7:1. Certainly not a problem with pump gas.

 

Self-ported World Castings S/R Torquer 305 heads (turned out to have 64cc chambers even though I didn't do any unshrouding, just polishing), Speedpro .030"-over 10cc dish/relief hypereutectic pistons, block decked .012" (put the pistons .026" down in the hole), .020" thick Victor Rienz head gaskets. End result is 9.7:1 static CR.

Runs fine on 87 octane unleaded and 10 degrees base timing. Track #'s indicate something in the neighborhood of 365 gross flywheel HP.

 

Thanks

My other option is selling them and getting another set.

I see a few vendors on e-bay now with good feedback selling 416 and 434 casting heads for 400 bucks a pair. They have larger valves 2.02 and 1.6. Would these be better than the world's? I could probably sell the world's for close to 400 to offset the costs.

What do you think would be best?

And in respose to above the motor does have the cheap non flattop cast pistons. They said they use Elgin brand stock replacement pistons.

 

Out of all those options, the World heads are the best. They would be better than any of the stock ones.

You might want to look at a cam while you've got it apart. A typical "rebuild" will have a 929 cam in it. Just about the bottom of the barrel, for performance. Major improvements can often be made there, for not too much $$$. Take a look and see if it's a roller before you order anything. Probably not; but you never know for sure until you look.

 

look into
http://www.racingheadservice.com
Eric B

 

So the World heads would be better than a set of 416's with the larger valves? Is that because the Worlds have better flow even with smaller valves?

I do have a better cam to use. My brother gave me one he was going to use in his truck. It is a 4x4 truck cam so it will have good tourqe. I'm not going racing so I'm ok with the top end not being real strong. Its is new and comes with lifters and a timing chain, best of all its free. The rebuilder also said he would knock off 100 bucks when I told him I did not need the cam, lifters and timing set.

 

305 heads do not belong on a 350, world heads or not. Sell em and get some 350 heads.

 

yep. A common old wives tale that bigger valves are always better. A properly ported head with no other changes besides valve size will flow almost identical. The world casting is better than any production GM head, it's thicker and the port is designed better. (okay, maybe not as good as a vortec casting)

uhmm, those world heads have more potential than any older 350 head. You dont have to take my word for it, go pick up David Vizard's book on it. Thicker decks and thicker walls allow more milling and larger ports, unless your comfortable welding cast iron or offsetting your intake valves- the world heads are far better.