I am trying to decide which stroke crank to buy for a 6.0 liter .030 over build. I started with the idea of using the 4.125 crank but after hearing that they have inherent piston side loading problems which lead to oil blow-by I am now considering the 4.000 crank. This car will be street driven with the new high cc AFR heads.
1. Which crank should I use for this build the 4.000 or the 4.125 and are the side loading problems for the 4.125 crank true. Are there any other pros or cons to either crank. Any of you guys that have done this please weigh in this is my first LS block build and I dont want to blow it.
2. Which brand crank is better I heard that Lunati, Callies, HTC,and Cola all make 4340 forged cranks for this application. Are there any major differences good or bad in they way they are built.
3. I have an extra set of Ross forged lightweight flat top lt1 383 pistons for 6 inch rods. Can't seem to find wrist pin diameter specs for the standard ls1 pistons, will they work in this ap or do I need to buy new ones.

Thanks In Advance

 

the ls1 has 3.9'' bores no?

 

If you consider the whole family LSx engines, bore depends on displacement:

6.0L has 101.6 mm bore (strange that it's not "hard metric")

5.7L has 99 mm bore

5.3L and 4.8L have 96 mm bores

BANDIT referred to a 102.36mm overbored 6.0L, I believe.

 

LS1 is a 5.7L 347 CI motor.

Gen III SBC is what you just listed- since you wanted to bust out the technicalities

 

So you're caught between a 408 and a 421 LS1. Good spot to be in.

If I was doing it, the 4.000" Callies would be my choice for a street motor.

The Ross SBC pistons probably will not work because of the compression height.

A Diamond or JE piston will work well for this setup, and I think that Diamond has a off the shelf piston for this.

I'm looking at getting some of the AFR bare castings early on to have ported for a Head/Cam daily driver.

Bret

 

What happened to the stock LS1 being a 346 CI?

And what is the difference between the LSx family of motors and Gen III SBC?

 

yes guys it is a 6.0 litre iron block
I was told that the standard bore for this block was 4.000 and so was going to take it .030 over. I priced the Callies crank through scoggins dickie and they want 1600 for it does this sound right? I know dean at callies real well so I may be able to get a better price through him so Im waiting on him to return my call. I was also told when i called afr that the heads will be available sometime in the Dec/Jan time frame for the bare castings so by the time i get all my parts they should be available. thanks for the piston info I will check Diamond today.