I wan't the 113 heads for my 91fbd w/ 305 tbi for weight reduction purposes, but I know you lose compression too. They come with 58cc combustion chambers but I hear 54cc will bring it back to stock compression. How much needs to be milled off these heads to maintain stock compression?

 

I know these heads are a 'perfect' match for 305 "TPI" (LB9) engines, which also had 58cc chambers. They are about 50lbs lighter than the stock iron heads, and flow better than the stock ones. I don't know about TBI though!

 

thanks for the quick reply, wasnt aware of this..well my other choice is the 059 vortec head (they have the same combustion chamber size as what I currently have)..could i just get those shaved so I have a few less cc's of chamber and a higher cr to where I can run 93 octane and make a little more power? what would be a good chamber size for this? Thanks

 

059 Vortecs use the same intake port/bolt pattern as the L31 Vortecs - your stock intake won't work. They also don't have the good chamber design that the L31 is so popular for. The 113 Corvette heads would be a better choice IMO - use the stock intake, and they are a slightly better head too.

 

ok whats casting numbers should i be looking for with 131 heads?

 

Just to give you a heads up, there's a ton of info on these heads on this thread, in case you missed it:

https://www.thirdgen.org/forums/tech...questions.html

Lots of debate and info on these heads...

 

Yeah I read it, but I cant find any threads with any real numbers. All i really want to know is which one makes more power, and where at in the power band, and also how much these two different heads can be milled for best possible compression on pump gas

 

They aren't a "perfect" match. Their aluminum 58cc chambers went on 350's that had 64cc chambers with iron heads. The extra static CR is needed to make up for the loss with the aluminum.

Rather than fooling around with factory castings, why not just get something ready to bolt on? http://www.summitracing.com/parts/TFS-30300001/

Perimeter valve cover bolt pattern, and '86-earlier intake bolt pattern, but they would be better than either 113's or 059's.

 

This is the centerbolt 87 up version http://www.summitracing.com/parts/TFS-30300005/