jbates346

Does anybody know the best "performance" heads for a 305. I know, I know, theres not much. So far all i can find are the Worldcastings S/R Torquer 305. Are there any other heads that will fit? Thanks for any help.

watajob

iTrader: (29)

I'm pretty sure I'm going with these: http://www.trickflow.com/egnsearch.a...8&autoview=sku Only a few bucks more than the World heads.

jbates346

Those looks awesome! About how much do they run? Has anybody tried these? I don't see if there CARB EO legal. Stupid California!

watajob

iTrader: (29)

About $1200 at Summit. $100 more than the World heads. Don't know about the E.O. thing. Send 'em an email. They'll get back to you.

flaming-ford

iTrader: (7)

wow i didnt know they were that expensive i'd personally run l98 aluminum or 113 casting or zz4 heads whatever you want to call them, a good set of 113s can be head for like 600 as opposed to your 1200 and probably flow as well......

just my 2 cents

BC GTA

The following post will give you all the information I found when researching 305 heads for a TPI set up:

https://www.thirdgen.org/forums/tpi/...tml?highlight=

Since I wrote that post I discovered there is a GM Vortec head for the 305 engine. Some of these heads require the use of a different intake base manifold. Some require external routing of the EGR passage. These factors will add to the cost of such a project.

The “best” head depends on what you want with regards to torque and horsepower at different RPM’s, what other modifications you have done, what other modifications you plan on doing and your budget.

Other head considerations are compression ratio especially when using aluminum heads and maximum valve lift if you have or are intending to install a cam or higher ratio rockers.

All these and other factors have been discussed in detail on several recent posts just waiting for you to search and find it.

FormulaL98

Personally I would go with a aluminum set of vette L98 heads (as they are already 58cc) and the only other thing you would have to change is over the egr (search vette egr on here). probably going to be the most cost effective way of swappoing heads on a 305. Just my 2 cents, I just couldnt justify spending 1200 bucks on heads for an engine that will forever be held back by valve shrouding due to the tiny bore size.

BC GTA

When using aluminum heads you may want to research the effects of heat transfer and that effect on combustion, power production, compression ratio and combustion chamber size. The 305 TPI engines came with cast iron heads with a 58cc combustion chamber and 9.3:1 compression ratio. If you use aluminum heads it has been recommended in car journals that you need to increase the compression ratio by at least one full percentage point i.e. up to 10.3:1. Consequently, for aluminum heads you will need something less than a 58cc combustion chamber. This could be achieved by milling the aluminum heads, but would result in added cost to this project.

FormulaL98

This is true, but not really a necessary step if you dont wanna spend the cash on more machine work. Your engine will be fine without bumping compression or a thinner head gasket can also boost compression and wouldnt cost much. Just something to consider i suppose

The reason why you can run a higher static compression with aluminum heads is that the material has a higher rate of thermal conductivity (lets more heat out) then cast iron, keeping the chamber cooler and allowing for more compression/more timing etc.

SilentBobZ28

iTrader: (5)

Edelbrock makes an excellent replacement head for the 305 lb9 or lo3 engines. It is part number 60859. It's a 60cc combustion chamber. Has 165cc runners to keep up the velocity needed for the smaller ci engines. Chevy High performance did a buildup with these heads on one. It gave significant gains.
They were also paired with the cam specific for these heads, and the edlebrock manifold. As I remember they picked up over a second in the quarter mile. However, retained fuel efficiency, dependability, and was still smog legal.

BC GTA

I contacted Professor Overdrive at Summit Racing on this issue of aluminum heads and heat transfer which provide the following response:

“It is true that an iron head will make more power than an equal aluminum head, because of heat, I have not seen anywhere that shows a " 1:1" ratio like that. I don't think you would see enough difference to notice it, except on a dyno. I wouldn't worry about it much.”

I suppose the higher flows and lower weight of these heads would offset any HP loss due to heat transfer from aluminum heads.

Do you have a link to the Chevy High Perfomance article.

SilentBobZ28

iTrader: (5)

I found this link to an 84 build up of a L69 http://www.chevyhiperformance.com/te...der_heads.html. I can't find the one of the lb9 build. If I can find the magazine i will scan it.