What would be better?

6.0 short block, mild cam, springs on 5.3 heads
or
6.0 long block, stock?

I am asking because I know the 5.3 heads will bump comp on a 5.7, just not sure if it would do it on the 6.0's. Also, I am wondering if the 5.3 heads would just hurt flow on the 6.0 internals. I would like to use the 5.3 top end, heads/intake and 6.0 bottom end. Just trying to figure different ways of perf; cost wise.

 

lq9 would be best, that would be a complete longblock. you would get the good flow of the 6.0 heads and the higher compresion too.

 

a cam and springs would be nice in that lq9 too.

 

The 5.3 heads the f-body guys are using are ported with 2.00" intake valves added to replace the stock 1.89" intake valves,the 5.3 heads have a combustion chamber volume of 61ccs,6.0 heads come fitted with 2.0" intake valve but have a combustion chamber volume of 71ccs.If you run 5.3 heads on the 6.0 you need to fit the larger valves,with the 5.3 heads on a 6.0 block you'll have about 11:1 compression.With compression that high I would go with a little more radical cam.