RE: MACHINED INTAKE MANIFOLD
The stock plastic iso blocks are junk! I have taken ones off new never run motors that were already warped. Toasted an engine due to detonation, later found out the iso block was seriously warped, letting enough unmetered air in that the engine was running too lean.
I use aluminum iso blocks on all my non QD engines now. At least when run with the teflon gaskets, they come back ice cold!, bag after bag of fuel, even in 100deg heat in the summer. I wouldn't have belived it either had I not seen it myself. No need for a water cooled iso block, lol....