I was thinking about the difference in power levels between the two following examples:

5.3L Truck A4
5.7L Fbody A4

Mods

5.3L w/ full bolt ons, 220 cam
5.7L w/ full bolt ons, 220 cam

5.3L = 320rwhp
5.7L = 380rwhp

Please do not knit-pick. This is for discussion purposes only. Okay, so why does the 5.3L make 60 less power to the wheels? Please list what you see as a loss and if it's a bit wacko, give an estimated power loss... at least an assumption.

I'll start off:
*Bore size
*Compression

What else?

 

Intake design/flow/tuning

Exhaust deisgn/flow/tuning

Valve timing, cam lobe design

DISPLACEMENT

and the list goes on.