I know you want to build the 5.3, I get that but I will tell you as many will, that there is no substitute for cubic inches and compression is free horsepower. Meaning a 5.7 with your heads will give you both cubes and compression because it will bump the comp up to approx 11.0 if I am not mistaken. I have done many head and cam swaps on 5.7's and it was relatively inexpensive due to the cc's of the 5.3 heads on a 5.7. The 5.3 heads would have to be welded up in the combustion chamber and massaged for the flow, very expensive if you ask any person with done up 5.3 heads on a 5.3. I have a 5.3 and thats what I am planning on doing with it, 5.7 or 6.0 should yield the same comp ratio and your not spending a crapload on it either. I think the quest for 400rwhp is gonna be a pricey quest, done cheaper with more cubes. Just my .02

 

how much more power will whe ls1 give over the 5.3? theres not that much difference displacement wise, i was thinking it would be pretty inexpensive compared to an ls1 build cause i can pickup take-off z06 parts cheap, cheap, cheap. Those will mate perfect for my 5.3 wont they? and be quite an upgrade for lil dough. Thats was my understanding, please let me know if i am mistaken. The diffence in hp between a 4.8 and 5.3 is only 15 hp for .5 c.i. (crank swap) there is only .4 c.i. between the 5.3 and 5.7 and they can use the exact same components other than pistons. How dont understand how there can be that big a difference between the two. Is there really?

 

the 4.8 and 5.3 have the same rod length and bore size just different strokes, the 5.3 and 5.7 have the same stroke but different bore and rod sizes, the 5.3/5.7/6.0 have the same stroke but the 5.7 and 6.0 have the same rod size but different bores.

 

what length of connecting rods can i use, will the ls1's work?