Thread: advice on twin turbo heads?

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OK, here's my take on it.....
If I wanted to build a budget twin-turbo street motor, I would build it low compression, like somewhere between 8.0:1 and 9.0:1 static compression ratio. Using these KB forged pistons will allow you to use anywhere between 68cc chambers and 76cc chambers when used with a 0.005" piston deck height and a 0.028" compressed head gasket.
https://www.uempistons.com/index.php...roducts_id=165

76cc heads would yield a 8.16:1 static compression ratio
72cc heads would yield a 8.46:1 static compression ratio
68cc heads would yield a 8.77:1 static compression ratio
I wouldn't use 64cc heads because they would yield a static compression ratio over 9.0:1. I'm sure you'll find plenty of folks who will tell you that you can run over 9.0:1 with twin turbos on pump gas, but I'm not one of them.

I would be looking for a set of heads that would flow really well on the EXHAUST side, like 200 CFM or more @ 0.400" valve lift. The heads will have no trouble feeding the motor on the intake side, because the intake will be under pressure, but the exhaust side is still going to have to depend on the piston pushing out the burned exhaust gases just like a naturally aspirated motor. If I had a set of heads that flowed 200 on both the intake and exhaust at 0.400" valve lift, I think I'd be satisfied that I could make good power. Of course, there is nothing wrong with a set of heads that will flow 230 or 240 or 250 or more on the intake side, I'm just thinking that a set of heads that flowed less on the intake side and had been ported on the exhaust side to flow 200 @ 0.400" valve lift would be cheaper. Maybe not, you'll need to talk with the providers and take their pulse on this.

I think I would begin by calling some of these racing head providers and asking if they had such a set of heads on hand that would qualify. I'd tell them that this is a budget build and that if they had a set of Gen I production iron heads that had been ported on the exhaust side but not on the intake side, I would be interested in talking about them. Call these guys on the phone and talk with them.....
"Hello, this is J Scott from Klamath Falls, Oregon. I'm interested in speaking with someone about a set of Generation 1 small block Chevy cylinder heads, probably production cast iron, although i would be interested in hearing about alternatives if the price was affordable". Have pen and paper handy and take good notes so that you can make sense of them later.

TriMark Performance - Performance Cylinder Heads

Weingartner Racing

Texas Speed and Performance

SPEIER RACING HEADS - SRH INFO

Slawko Racing Heads

JONES ENGINES DEVELOPMENT - RACING ENGINES AND DYNO SERVICE - LANCASTER, CA - PHONE 661.942.3364

https://www.cityfos.com/company/Ron-...MO-2134691.htm

Total Flow Products - Cylinder Head Repair, Race Engine Cylinder Head Porting, Race Engine Cylinder Head Repair

MadCap Racing Engines: Rocky Mountain Horsepower

RHS - Racing Head Service

HRD Racing Heads - Cylinder Heads, Ford Racing Engine, Ford Cylinder Head, Racing Heads, Chevy Racing Engine

West Coast Cylinder Heads - Home

https://mikesracingheads.com/

https://www.headsupcylinderheads.com/

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