I actually went through this months ago but I've been meaning to discuss it here to see what folks thought.

Engine is a 2004 5.7L Hemi for a buddy's car. First 5.7 I ever worked with. It was knocking when he got it, looked like it was run out of oil and then ran hard, lost two rod bearings. Tore it down and decided to just use the block/replace everything else in the bottom end.

He bought a brand new crankshaft, rods, pistons, rings, and all the bearings from Mopar. Prices were surprisingly cheap for the mundane stock stuff like that.

Anyway I spent some time checking it out...

Clearances:
Mains: .0028 to .003" across all 8
Rods: .002 to .0025 across all 8
Piston to wall .0012 to .0015 across all 8, normal for a cast or hyper piston, always has been

Checked the service manual, everything was in spec per Chrysler. So...being that the clearances are basically the same as a V8 from the sixties, what's up with the myth "Modern engines are built tighter"? It's really no different from my 1968 318 2 barrel in that dept.


+ or - tolerances may be slightly tighter on the machining end, which I guess I'm on the receiving end of... but recommended final clearances appear to be pretty much the same as always.

Thoughts?