I'm in search of the perfect heads for my 383 TPI project.

They need to have:
180cc intake runners
1.94 or 2.02 intakes
1.5 or 1.6 exhaust
EGR passages
64CC chambers (58CC if alum)
Able to accept ~1.4" springs and a .560 exh lift w/o too much added expense (to support the LPE cam I want to use).
Screw in rocker studs
A combustion chamber design geared towards mid-range torque.

The lack of EGR passages rules out the Vortecs', the Corvette L98s', and quite a few of the aftermarket options.

Any suggestions??

 

If you have the money, I'd get AFR 190's, although they do make a 180cc head too. Just curious, why the 180cc?

 

Port and polish a set of 305 heads. You can hog out the intake runners easily enough, machine the spring seats out and use a little thicker gasket to get it out to 64cc. Then have the intake seats opened up for 1.94 valves.

A little bowl blending and exhaust polishing and you are set. They will flow just like a set of Vortecs.

No kidding, people are turning to these 305 heads left, right and centre--simply because you can MAKE them into whatever you want.

350 heads are often just too large in critical areas, while the 305s can be shaped outward.

 

Umm....

I respectfully disagree with that last post.

All that work and you could have bought the vortecs which with a little more work would be great. I would port some 305 heads for a 305 or a low buck 350 but not a 383 that you want to go fast.

The other big thing is= "Add a thicker head gasket to lower the compression".
This is a horrible Idea. Have you ever heard of quench? the only way that would work is if the block was a true zero deck and you used a gasket less than .050 Which would not get streetable compression on a 383.

Personally I would check out world products or Pro-topline. Maybee some L98 allums? Idont know much about them though.

 

Well, go for Vortecs and then you must also change your manifold. For TPI that means a Scoggins-Dickey outfit at $400 a pop. Suddenly the Vortecs are not so attractive.

F-Bird'88 is, in fact, getting Vortec flow bench numbers from his 305 castings. I also just did a set according to his instructions. Trust me, they work

To achieve an increase in combustion chamber size of a mere 6 CCs (58cc to 64cc) would not even require a head gasket of .050 in thickness. Probably .025 would do it, considering a stock 305 uses .015 shim gaskets to achieve 58 CCs.

305 heads can be had for a song, maybe $40 for the set at a wrecker! All of the machine work, valves, springs, etc., will run maybe another $300 tops. Then you put in 20 hours of your own time in porting, polishing, etc.

That's maybe $400 all told for a set of KILLER heads that will match up perfectly to his current TPI intake and flow like crazy :hail:

Compare a set of World Products heads at $750 or so, or the Vortecs and accompanying intake at $850 minumum.

So, now that your concerns are addressed, I expect that you will endorse my recommendations quite heartily, eh?

 

Hmm obviously you failed to read the original post.....

 

You could improve your stock TPI heads. They have a few things
going for them.
1. You allready own them.
Give them a good porting and add new 1.94x1.60 valves
along with a 3 angle valve job and you'll have a good
moderate performance street head.
I'd favour the 081 or 083 TPI castings.

 

Thx for the replies!

I have the 083 castings now.
There are 2 things holding me back from using them:

Price: By the time I have replaced all the parts and paid for the machine work, I will have spent close to what new heads cost.

Porting: I don't know enough abt it to be able to get matching/optimal flow on all cyls. Having it done is cost prohibitive. Polishing although wouldn't be a problem.


I haven't considered the 305 heads before, but the porting work concerns me.

I was thinking the AFRs didn't have EGR passages. I may be wrong abt that. New ones are also kinda expensive for by budget.

I'm aiming for 180cc runners cause that is what Lingenfelter recommends (for 350-383 street engines).
I'm trying to use one of the LPE engines as a model.

Any other suggestions?

Is it possible to make an EGR passage in a Corvette L98 head?

 

You could rig up an external EGR setup deal for the L98 heads where it taps into the exhaust manifold and reintroduces it in the intake manifold. I don't know why anyone would go through so much trouble to use L98 heads.....

 

Click here for a downloadable guide to porting and polishing:

http://www.sa-motorsports.com/portdiy/diyport.pdf

Then read this thread:

https://www.thirdgen.org/techbb2/sho...hreadid=117410