Go with a Gen VI over Gen V. Email me, I know of several available, new and used.

Kirk

Remeber, you now have to go to an electric fuel pump....

I would like a lo of things... including Gen VI 502's !!!
The reason I am looking for a Gen V is I need twins and I now have one Mark IV & one Gen V. So, by choice I am trying to match to the Gen V and buy only one block not two!! I will still have a Mark IV left over after the conversion. The electric fuel pumps were already on my "need" list.

Now, if those Gen VI's are really reasonable,,,,let me know!! I would LOVE to have them!

Does anyone know the difference between the gen v and the gen Vl?

The main difference to us boaters is the VI has a fuel pump mount, the V does not. You will not notice any difference between the V and VI if you run one of each except the fuel pump mount. There are other differences for land-lubbers. I would try to get aftermarket heads. Merlins are cheap and great. The CI GM piece is no match for Merlins or almost any other aftermarket piece. If you find some cheap and in good condition and are on a budget, they will work.

Mark IV heads will work on a gen 6 block but not on a gen 5 production block due to the changes in the cooling holes. Gen 5 heads will work on a gen 6 block too. Mark IV heads will work on a gen 5 bowtie block though. as previously stated, no mechanical fuel pump pad on gen 5 but it's back for gen 6. Mark IV is a two part rear main, 5 & 6 are one. main cap bolts on Mark IV is different length than Gen 5. Mark IV valvetrain is adjustable, gen 5 isn't but can be made adjustable. oil systems are different as well.

Ok, so does this mean:
A MK IV block will work with a MK IV crank & Gen V heads & intake, and a MK IV pan? will have adjustible valve train.

A Gen V block, MK IV crank w/adapter, Gen V pan, GEN V/VI heads
and valve train is not adjustible.

If the MK IV/Gen V head combo doesn't create problems like push rod lengths, then.....

Maybe I would be better off trading a Gen V block, crank & pan for a MK IV block, crank & pan??? Any takers???

Blown Formula,
You can use the V and VI heads on the IV block, the intakes interchange. Just ask your machine shop about the differences-more than I want to type, but not too bad.
Adjustable valve train on V and VI heads is no problem for any good machine shop and the pushrods, etc. are the same length, etc. Parts for this are the same as the parts for IV or Mercruiser 500hp or 502EFI. pm or call if you want more.

need help

it looks like Jeg's has them in stock