I have been studying the differences between the Gen IV(1965-1990), Gen V(1991-1995), and Gen VI(1996-present) Big blocks. One of the "improvements" from Gen IV to Gen V is the water jackets. When the blocks were cast, the jacket holes on the deck where the heads meets the block were enlarged to allow better coolant flow. Does anybody know if there is much difference in operating temps from the Gen IV to Gen V's?

Bill

I would guess the bigger coolant passages would be because the new blocks and today's technology are capable of much more horsepower with means more heat, thus additional cooling capability is needed to maintain the same operating temperatures.

The engineers at GM have to know many of these blocks will be retro-fitted into older cars with their contemporary cooling systems and have to keep that in mind so they don't have blown engines coming back and have a warranty nightmare.

That makes sense gunslinger.

I have a Gen V 454 short deck from a 92 K-3500 truck that I am building for my 78, so I am hoping that with the larger water jackets, that I will not experience the temp problems that are common with the Gen IV engines in the C3 Vettes.

But like you said, the more power produced, the more heat generated. I plan to approach 500 HP at the flywheel.