JakeFusion

iTrader: (7)

I found a built 383 shortblock for boost that is built on the LM7 platform (not ideal - would prefer L33)... but whatever.

I know long strokes are frowned upon in iron blocks because of the sleeve length... which is why LS2 is popular or the 370/390 stuff. But I'm wonder if the LM7 has the same issue as the LQ4/9?

Or is that even a problem? I'd prefer the 3.622" length crank, but this is a prebuilt deal that has a 4.000" K1 Crank, Compstar Rods, Wiseco Pistons, ARP Mains, and rings gapped for boost.

Any guidance?

kinglt-1

iTrader: (26)

I think it would be fine but you might get better answers in the FI section.

Mavn

iTrader: (3)

Run it

JakeFusion

iTrader: (7)

Well I just wanted to know if the sleeves were short in a 5.3L block. Otherwise, I could just build my block for about the same price as this motor.

Tuskyz28

Jake, I would THINK a custom designed piston is what you'll need and suit your needs.. I'm positive that wiseco can hook you up.

KCS

iTrader: (20)

I just measured a bunch of blocks with a 12" dial caliper and got some interesting results.

Here's a Gen IV 5.3L iron block, casting number 12576177:


Measuring down to the end of the cylinder:


The caliper is showing 5.539":


Now here is a 6.2L aluminum block, casting number 12621766:


Measuring down to the edge of the sleeve. Notice the chamfer on the sleeve and the step where the aluminum extends a little further. This is not part of the sleeve length that could support the piston:


The caliper reads 5.464"; that's .075" shorter than the 5.3L block:

JakeFusion

iTrader: (7)

That is interesting. Do you know if the Gen IV 5.3L bores are the same as the Gen III? I've been looking at picking up an L33 since it's essentially an LS6 block. But that looks like it'd support a 4" crank no problem then.

KCS

iTrader: (20)

I'll look around next week and see if I can find one. I just saw a bunch of Gen IV blocks. I saw an LS1 block that was about 5.540" so I'd assume a Gen III 5.3L would be pretty close to that.

sbdgbody

iTrader: (11)

I just measured my gen3 5.3 aluminum block I got 5.650 this is for my 383 project bored 3.905 with a 4.000 crank

JakeFusion

iTrader: (7)

Then it sounds like an L33 is a good option for a 4" stroker crank and boost.