i have a pair of 327 camaro double hump heads i want to put on my 305 tpi when i carb it. my question is will i gain any power when i install these heads? i know i will lose compression because i am going from a 58cc combustion chamber to a 62 cc but these heads also have bigger valves and larger intake ports so will the added flow make up for the loss in compression ratio?

 

No

 

Get a set of Vortec 305 heads.

 

Compression ratio builds torque. Head flow makes HP. Larger valves depends on just how large. 2.02/1.60 won't fit inside the 305's small bore. I think 1.94/1.5 is the max you can use.

Your "double hump" heads probably also don't have accessory bolt holes so alternator and power steering brackets won't fit.

30+ year old castings have no place in modern performance engines. Even if they were free, unless they've already had a lot of work done to them or you can do your own machine work, it's cheaper to just buy new aftermarket heads which will be better right out of the box.

 

I'm with Steven, they aren't worth the trouble.

And you know what...? Those 305 TPI heads you have now are probably just as good, performance-wise, as those 327 heads (stock vs stock) maybe even better.

Don't count those heads out just because they are 305 heads, if they are 416 or 081 castings, then they actually are quite good for a performance build.

 

Yes, I have 416's and was told anything bigger hurts performance, besides just to get the 1.94's to fit a 305 it needs an overbore. Just have some port work done to your stock heads, or go buy a 350 block and make use of those other SBC heads you got.

James

 

ok i will leave them off of my 305. i plan on building a 327 i will save the heads for it. thanks for the replies

 

Sweet, I love 327's, prob my favorite SBC, let us know how that goes.

 

Or better yet, use your 305 heads on the 327... they actually are better heads. Performance wise, they are pretty similar (but better IMO) and they will be easier to work with, as they have the needed accessory holes and hardened valve seats in them already. The 305 heads have the same size ports as the 327 heads (roughly 165cc) but have slightly smaller chambers of a better design than the 327 heads, so they will be better heads on a performance engine. I used a set on my 350 and loved them, as have others here.

 

Thats really interesting.

 

My old 305, I had larger 1.5 or 1.94 valves installed. Can only do one or the other and not both.