LS1LT1CAM

thinking of putting 4.8l crank in a 6.0l block (330 cu in) with a 72mm turbo on it for the street race class in the nmca

ninetres

iTrader: (35)

I'd run the 6.0 crank but that's just me.

67Firebird455

iTrader: (27)

That makes two of us... =)

DaGreightOne

I'm a destroke kind guy also... I love the sbc 377 and the bbc 427 so I share your sentiments. I have a APS kit now and need to build a shortblock I was thinking of going with a 6.2 (4.02 I think) or 7.0 (4.125) block but with a 5.7 crank. I just think large cylinder walls and short strokes are better for turbo cars, I need quick spool up times because I want to my upgrade turbos.

ninetres

iTrader: (35)

More cubes spool faster. I don't think going from 364ci to 330ci is going to make the car spool faster. I do realize the effect of shorter stroke revving faster but I fell the speed of a 364 stroke combined with more displacement will still be the better option.

Big Bird WS6

iTrader: (9)

what i don't number stand is the 402 and 408 turbo builds. why stroke it. let the turbos do the work to make the power. and let the engine run like normal

MY99TAWS6

iTrader: (3)

The 408 and 402 are much better off boost and they will spool up the turbos faster than smaller engines. They still rev up plenty fast. For a street car they are hard to beat. Love my built 408. Also with a bigger built engine you will simply make the same power as the smaller engine at lower boost or more power at the same boost level as the smaller engine. You start with 100 hp more say to begin with .You may not want to push the turbos say to 20psi or beyond. Might have head gasket issues for one thing. Running 15psi and making 1000 engine is usually better than running 20 or more to make 1000 engine. And you still wont' have the off boost torque of the bigger motor.
Also think compression plays a role in spool up as well.Higher compression pretty sure will spool up faster.
I went with 9.5 in my 408. No complaints. Was going to go 427 but that really did seem like overkill for my purposes. Think 402 or 408 is nice middle ground. 370 with stock crank would be good for budget build.

67Firebird455

iTrader: (27)

More displacement, less "resistance" or "pressure", so more volume of air for the same amount of "boost". Larger displacements motors will take a lot more air/fuel for the same amount (psi #) of boost than a stock, or smaller displacement motor.

Pro Stock John

iTrader: (34)

If the class limits CI, then yeah try it, but if not, then as one veteran engine builder says, run as much stroke as you can because it will get the car to the 330 with more stroke.

DaGreightOne

Something to think about...

camarols1

iTrader: (17)

I agree with PSJ, that there is no reason besides class CID restrictions to build a smaller engine.
A longer stroke will help the turbo spool more than a bigger bore and shorter stroke.
The stock 5.7/6.0 crank is a strong item and a good foundation for a turbo build.
Also, the pistons are going to have to be custom built for the application which will be more $$$ than shelf parts for a 5.7/6.0 build.
There are many 1,000 HP 5.7/6.0 builds out there with a stock crank, so I see no reason to spend more money for less power.