no machine work is needed to convert a 4.8 to 5.3, I did a little math and if you wanted a 6.0 you could use the 4.00" storker crank with .060 overbore to achieve 370c.i. or 6.06 liters, with no overbore and just the stroker crank you get 359c.i. or 5.98 liters

All these combos would be with using the callies 4.0'' stroker crank, which will fit into 4.8, 5.3,5.7, or 6.0.

.030 365c.i. 5.98 liters
.060 370c.i. 6.06 liters
.090 376c.i. 6.16 liters
.120 382c.i. 6.26 liters

This will work but the cost of the crank and rotating assembly would be rather high. Hope this cleared some stuff up, and also would like to see someone fork out the dough for one of those cranks.

 

I believe they have different part numbers because they are all BALANCED differently. When you're swinging different weight pistons, you have to add or subtract weight from the crank counter balancers to maintain a vibration free engine.

 

Someone in the thread I mentioned said they pulled one from a 5.7 and from a 6.0. They both had the same part number stamped on them. I don't know if maybe that was just a generic number for the crank, and there is a different one for the engine specific one that would be balanced.

Here is another question for those in the know ... Are the 5.3 and the 5.7 cranks made of the same material, and are they the same strength? If this is the case, what would keep us from spinning these motors to speeds they are turning the ls1's?

 

The 4.8 and 5.3 have the same bore, different stroke. The 5.3, 5.7, and 6.0 have different bores, but the same crank DIMENSIONS, but I think the 5.7 is lightened.

 

nothing keeps you from turning the same rpm's except for your rev limiters, the engines will handle the higher rpm. However you must make sure everything is balanced, use the correct connecting rods, pistons, etc. also you would want to make your heads flow more to keep up with the engines higher rpms.

 

Here's a 5.3 crank on the left, 5.7 in the middle, and a 6.0 on the right. As you can see the 5.7 is the only one that has a hole right thru the middle of the main journals.



Here you can see that the 5.3 and the 5.7 have the same casting number, but obviously would have different part numbers.



The 5.3 and 5.7 are balanced differently also.


This shot shows the crank flange on each. This is an early 6.0 with the thick flange. Unless you are sure you are going to use a 4L80E, you DON'T want this crank.


So the 5.7 would be a lighter crank with the big hole thru the middle, but if using it with anything other than a 5.7 setup, I would think rebalancing would be required, as with any of these cranks when being used with different pistons.

 

Awesome pics and explanation.
Thank you Speartech!

 

Great explanation and I'm sure that clears a lot of things up for most of us. I agree though if you were to take the 5.7 crank you would need to rebalance it a little.

 

Anythime you rebuild you would want to balance your bottom end. You would definately want to upgrade your heads if you plan on turning those higher rpm's.

 

So ... giving the same casting numbers on the crank ... it would be safe to assume they are of the same material, which would be the same strength. Correct?

I'm not worried about the heads, cam and rev limiters, those are not the issue here. I'm more worried about a peep hole in the block being formed from turning 6500+ rpms on a 5.3.

The only other downside to this would be the need for a tach since the one in the dash doesn't go past 6 grand.

What do you thnk about these assumptions John?

I talked to Matt at CompCams about a cam. He said since they are the same crank and a little shorter rod, being a shorter stroke, that it should be safe to turn these to somewhere around 7k on a stock bottom end.

Would anyone argue this? If so .. for what reason?