Would the heads meant for a turbo car be ported any different than heads designed for a N/A setup?

 

The main thing is they need to be lower compression heads..... What I know a lot of people do is take 6.0L truck heads and upgrade the valvetrain.... hope that helps?

 

i would go with LQ9 heads. I believe they come on the escalades and trucks like that.

 

What about LT1s? Kinda screwed because of the reverse flow heads.

 

Oh my bad man, I didnt realize it was an LT1, sorry I dont know anything about LT1 heads.Maybe someone will chime in.

 

I've seen over 1000 made with ported stock heads!!!How much power are you wanting????

 

Can't you get LT1 AFR's that are pretty good? I'd look into a set of those maybe with bigger combustion chambers than stock if you need to work on your compression, and plan to run a lot of spring pressure.

 

trick flow, 62 cc's compaired to the stock 54-58 cc's, that and the flow on them is like 250 intake and 190 exahust stock cast. can flow over 300 and 250 ported.

 

No one has answered his question..
I'd guess that port volume can be increased over N/A heads. The heads I have on my truck flow decent numbers @28 inches of water but out flow the best heads out there when the flow bench is turned up past 28"'s

 

Yes, they would be in an ideal world. The I/E flow ratio would be skewed to favor the exh ports over that which a set of heads intended for a NA or supercharged application would shoot for. The chambers sometimes are modified differently as well - it all has to do with the exh. flow "resistance" & tremendous heat a turbocharged engine sees, that a NA/supercharged engine never has to deal with.

The heads would also be "built" differently for a dedicated turbo application as well - valves, guides & seats all have specific wants, specs, & materials to live with the heat a dedicated turbo engine makes - and it goes without saying that the cam timing for a turbo'd engine is completely in it's own world as well

NA & supercharged engines heads are built essentially identical - turbos aren't.

 

During my last rebuild, I regret not doing this:

With the AFR heads, you can upgrade to a 1.625" exhaust valve without changing the valve seat. It's simply a valve job and bowl blend away. . .

Mike

 

So should I opt for a different valve size other than the fairly standard 1.600, 2.02 valves?

Also what has to be different about the seats? Would a five angle valve seat be sufficient?

 

Is there any difference between OEM and aftermarket LT1 castings, in terms of deck thickness? If so, and if it's significant, I would go aftermarket. I don't anything about valve sizing, but I'd at least go 2.02/1.57.

 

The 1.625" exhaust valve is better, but maybe not worth the cost/effort.

5 angle would be good, but a good race engine shop can do a full-radius valve job.

AFR decks are thicker than stock LT1.

Mike

 

What is stock deck thickness, and for the AFR's?

 

Maybe this question is better suited for Advanced Tech, but which is more preferential: a smaller combustion chamber on the heads w/ a deeper dished piston, or a larger combustion chamber w/ less dished pistons? For example, if you're shooting for the same compression ratio e.g. 8.5:1, which is the better way to go? I'm planning on running a turbo on the stock short block for a while while I save up for a built bottom end, so I'd hate to spend much money on a set of LQ9 heads to lower the compression ratio now if I'm gonna have to turn right around and buy another set of heads for the lower compression,forged bottom end. Any insight on the subject would be greatly appreciated.

 

Great question. I always thought the less the dish the better but then again we really don't have access to more than 72cc heads. So maybe it does not matter. I have heard of folks mirroring the pistons to reduce the potential of detonation.

 

Its always recommended to use large dishing of the pistons as a last resort.Get larger cc heads or a slightly thick gasket.The piston's are thin enough as they are and using a very large dish just makes them even thinner.

 

yes, both trick flow and afr's are thicker than stock, and what are the chamber sizes and flow of stock casting afr's?

 

Excellent < / Mr Burns > Thanks for the advice Pro Stock & ddnspider. I guess my only other big concern for the moment (as far as heads go) will be what size valves to go w/.