Has anybody put the #10088113 aluminum Corvette heads on their 305's? Do normal block hugger- type headers for third gen F- bodies fit the raised exhaust port openings? And will the same headers work OK with the angled spark plugs? Thanks.
Hey, normally technical questions are better asked in the Technical sections of the boards rather then the regional sections, which are more for gatherings, shows, etc. I've moved the post for you.
It's like putting a 64cc iron head on a 305 - you'll lose effective compression. Whether you want to do something about that depends mostly on future plans, like going with a 350 shortblock sometime in the future.
"...normal block hugger- type headers for third gen F- bodies"? Not sure what you mean there. Block hugger headers won't fit without major mods to the engine mounts. "Normal" 3rd gen headers like Hooker 2055HKR are shorties, not block huggers.
Vette heads are actually 58cc chambers, just like your stock cast iron heads, so no loss of compression. Standard exhaust headers will fit and seal up, despite the D-shaped exhaust port on the Vette heads.
They have the 85-down intake bolt pattern so they will even take a stock intake manifold if yours is 85 or earlier.
They do NOT have exhaust crossover ports on them, however. Your EGR system will not function if you plan on using it. Many delete it's operation in the chip. Earlier computer controlled carbureted engines many people get buy without doing anything, while others get EGR errors spitting out of the computer- seems to be a hit-or-miss kinda deal with that.
Vette heads are actually 58cc chambers, just like your stock cast iron heads, so no loss of compression.
Same static compression, but like I said, lower effective compression. Those heads were used on an L98 350, and iron L98 350 heads were 64cc. Aluminum transfers (loses) heat more rapidly than iron, and heat = energy = power. More heat transfer, more energy loss, less power. The higher static compression ratio makes up for that power loss.
You'd need to shave the heads to about 52cc to get the same power out of them as 58cc iron heads.
Agree with the rest of what you said (except it's '86-down intake bolt pattern. . . ).
OK, shorty header then instead of block hugger. I've never had a set of heads with angled spark plugs before, will I have clearance issues with the 3rd gen style shorty headers and the angle plugs? I'm not concerned with the EGR passageways in the heads, or the computer programming. I will eventually be wanting to change over to a conventional carb and distributor system and run without any computer control.I see what you mean about the aluminum/cast iron 58cc/64cc and will think about having the heads milled to 52 cc's. That's what I am trying to find another way to do......... I really want to run my vortecs but don't want to lose the compression via the 64 cc's, nor do I want to mill this particular set of heads. For the time being I'd like to play with the "tiddler" 305 and I don't want to mill my good vortecs in case I want to use them on a 350 someday.Also, do you think I could run 1.6 ratio rocker arms on either the stock Berlinetta computer controlled carb 305 heads or the Corvette heads without having to elongate the pushrod holes in the heads (using stock Berlinetta, non- Z28/IROC smog cam)? What about with the cam from a stock 1986 Z28 (non-IROC, computer controlled carb)? Would the 1986 base Z28 cam have higher lift and duration numbers than the Berlinetta cam? The car is a Berlinetta with the original engine, but I have access to a complete 1986 non-IROC, computer controlled carb 305. Is this Z28 engine any better than the Berlinetta engine performance- wise? Thanks!
Z28, Berlinetta, Sport Coupe - didn't make a lick of difference. An LG4 is an LG4. The LB9 got a little better cam in '86, and much better exhaust, but the body style didn't affect the engine.
The stock heads may need to be opened up for 1.6 rockers. The Vette aluminum heads use guide plates, so not a problem. 1.6's wouldn't make a big difference on a stock cam.
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