Ok, so I have been tossing around heads that will benefit my 305 but support 380-420hp on the 383 I am building. I have been tossing around 113's and 128 vette aluminum heads. They are both 58cc so my LB9's CR wont be changed. I have done some searching but I cant find any I/E port cfm numbers, anybody know?. I currently have stock 416's which I know are 165/59. I have an 86 motor so I like the idea of the 128's since they will pre 88 heads like I already have. But I would like to go with post 88 roller motor, will this be a problem or should I just go with the 113's? My current LB9 is mostly stock with a 420/442 204/214 cam, 1.6 rollers and a bunch of other little things here and there. I plan to have a complete top end gasket match when I get what ever heads I decide on and I believe this will benefit my 305 greatly and transfer over to my 383. Sorry for the long post, any input? Thanks. James

 

113s flow about the same as the 416 heads, stock VS stock. And the 58cc chambers will make WAY too much compression for a 383, more than likely. On a 305 they'd be great, but not a 383.

 

Really? I was told with a good port the 113's flow a hell of alot better which is what I'm going to have done, plus the advantage of the 1.94's over the 1.84. I plan on running dished pistons in the 383 if I go with L98's. I've heard many good things about ported 113's over ported 416's. Plus the over 20lb weight loss a peice. Anyone have any experience with these?

 

Depends whose numbers you believe. Here's a link to some heads that have been flowed by members on this board as well as from some other sources.

https://www.thirdgen.org/forums/tbi/...-headflow.html

Looks like the common 305 heads (416s, 081s, etc.) do half decent compared to the Vette 113 heads, at least on the intake side. The Vette heads have better exhaust ports (by 20 CFM or more).

If you're going to buy any heads for later use on a 383, the old Vette casting would not be my choice. Aftermaket heads these days are SO much better than old factory stuff.

 

113's are 350 heads. When put on a 305, they are an effective compression drop, just like putting 64cc iron heads on a 305.

 

I thought the 113's and 128's had 58 cc chambers?

 

There's no such thing as a good head that will work on both a 305 and a 383. Just keep what you have on the 305 and spend the money on the 383.

 

The mathematical compression ratio stays the same, but because aluminum loses heat so much faster than iron, the chamber does not stay as hot, and effectively acts like its lost about 1pt of compression ratio. Aluminum heads REQUIRE more compression just to level the field with iron heads. Heat = power, aluminum loses heat too fast, compression creates heat. Thats why aluminum heads NEED more compression to be even with iron heads.

 

Well thanks for all the info guys, I guess people build up the aluminum 113's to be better than what they really are. Looks like I'll just do a home port on my 416's since I always hear good results.

 

Just to play devil's advocate;
Here's a Carcraft article testing Aluminum vs Iron.
http://www.carcraft.com/techarticles...o_results.html
". Regardless of coolant temp, rate of acceleration, steady state, or through a sweep, the dyno curves for the two styles of heads were identical. If anything, we could squint and guess and mumble that maybe aluminum heads were better by 2-3 hp. But the one thing we could never say is that the iron heads retained more heat and made more power than the aluminum. "

Here's another Aluminum vs Iron test from ChevyHiPerformance:
http://www.chevyhiperformance.com/te...ads/index.html
"The aluminum heads made an average of 8 lb-ft of torque more than the iron heads throughout the entire curve, which contradicts our theory that iron heads should produce more power."

Apples and oranges?