Are 1998 502 EFIs gen. V or gen. VI blocks? What is the diff between the 2?
Thx,
MD

I know they are Gen VI, but I can't tell you what the differences are.

A 1998 is a Gen VI. The big difference is the roller cam/lifter setup. The lifter bores are taller with a guide to keep the roller lifters from turning, Gen VI also has a cast aluminium timing chain cover with six bolts instead of ten. The harmonic balancer also is marked in degrees. Another big change is that the Gen VI can accept Mark IV big block heads supposedly and the Gen V could not due to the size of the water passages. Also Gen V & VI have a one piece rear main seal vs a two piece in the Mark/Gen IV. Also the water flow and internal oil flow pattern changed some in the Gen V & VI vs the Gen IV.The mechanical fuel pump option is also gone in Gen V & VI block vs Gen IV.

Pismo10,
Thanks for the input.

Dean

Are there any valve springs,annual Impeller change out or periodic maintnance related items I should worry about other than the Ex. Manifolds, annual Impeller change out, ?
Thx,
Dean

ttt

502 EFI ?

You mean 502 MPI?
or
a blue 500EFI?

blue motors need more attention to springs and lifters.
black motors only need gasoline and an occasional oil change. pretty much forever.

mcollinstn,
502 MPI is what I meant.
Thanks,
Dean