ORIGINAL: Jeremiah 29:11

I kinda listed some of them in anothe thread:

They are are just simply different engines.

1. higher compression ratio

2. Bigger bore

3. high flow heads

4. larger valves

5. intake manifold design for higher rpm

6. exhaust manifold is tubular in design

7. higher flow fuel injectors

8. higher flow air cleaner

9. A nodular crank on the 5.7L vs a forged steel crankshaft on the 6.1L

10. Cylinder block has reinforced bulkheads for higher engine loads

11. Larger bore diameter

12. Cylinder bores are hones for reduced piston friction

13. Higher performance flat top pistons to support the higher compression ratio.

Too numerous to list all.

Botttom line is there are a lot of differences between the 5.7L vs the 6.1L.