So, if only the mains are drilled that means the recipricating mass should be the same. Meaning there should be no performance difference between them. This is good info...maybe someday building LS1's will actually be affordable.

 

That's what I would think as well.. They only upside to the 5.7 crank that I can really see is that the drilled main may provide better oil flow/pressure venting between the inner sections of the block... Dunno if it's enough (if at all) to really be noticeable though.

On the upside, I would also think the 6.0L truck cranks would have a little less bob weight taken out in the balancing process, as the pistons are going to be ever so slightly heavier than the 5.7L, which may be helpfull if you're doing a forged rod/piston setup. Along the same lines, a 5.3L crank while physicaly the same as the 6.0L crank will likely have more bob weight removed from the balancing process, and *may* require the addition of more metal (what are they using nowadays to do this?) to make up for a heavier piston/rod setup...

Country Boy: No worries! The more people out ther with accurate information, the better!!!! Glad I could help out!

 

Now we gotta have the weight to the 5.3 crank. Do they weigh the same?

 

Damn man, we haven't torn down the 5.3 yet.. Get to it ASAP, right Matt..

 

ummm sure! Not like I have any other projects going on

I'm still not convinced that's a 5.3, I think it's a 4.8 still.....

 

Mallory (heavy metal) is usually what is used to add weight to the crank in balancing.

 

Here's another twist ... gmpartsdirect.com shows different part numbers for all 3 of the engines in question.

I've wondered too if the ls1 and the 5.3 have the same crank. If so, that would mean the 5.3 should safely turn 6500+ rpms.

 

The reason I think it's a 5.3 is because of the dished pistons..

 

Weighed the 5.3L crank and it came in at 53 lbs.

 

just wanted to add some more info to this thread....

I took my rotating assembly up to my machinist a couple of weeks ago to have it balanced. I took him a 6.0 crank to use. Ended up only having to add 11 grams to the rear counterwieght and 7 grams to the front counterweight. Since it was so little mass to add, there was no need to use the expensive heavy metal that's commonly used. The guy also said that he balanced an almost identical setup that same week (weight-wise on the piston/rods), except that was with an LS1 crank, and he had to add a good amount of heavy metal to the crank. He couldn't recal the exact mass amount, but the additional cost was over $100

All in all, the use of the 6.0 crank saved me over $100 since the guy just had to use some welds and regular steel on mine, instead of mallory.

Just wanted to add that to the conversation, since cost is ALWAYS a factor, and if you can save a decent chunk of change on balancing by using the 6.0 crank, then I though it'd be worthy to mention on here.

BTW, I've got a few good 6.0 cranks I can sell as well

 

just FYI my SCAT 4" crank weighs 48 lbs.

 

Another addition to this thread: (couldn't find a decent post of mine to edit, so I'll jsut tag it onto the bottom)

All these cranks that bigeller weighed had the timing chain sprocket still on the snout, and the 5.7L crank had a pilot bearing in it (the 5.3 and 6.0 cranks did not), so it was never an inequity between the weights (aside from what little a pilot bearing weighs), however, this was all done on a bathroom scale zero'ed out before each weighing. I can't say that it's version of 5x lbs is in fact that number empericlly, but what has to be considered is the difference in the weights.