Will Gen 5 heads work on Gen 4 block??

[OldFaithful Squirter]

Head Gasket- Tech Question?? 454 Gen 4 & Gen 5
I have done some internet research and have found from Fel-Pro there is a head gasket 17042 Marine HP that claims it will fit a 1960-2003 454? So is there anyone out there that has ever put Generation 5 heads on a Generation 4 block? It states on Fel-Pro's website that this gasket will work, and I was curious if anyone has ever done it? Any help with this subject? thanks KC
This part fits these vehicles
Make Model Year Body Engine Other Info
CHEVROLET ALL MODELS 1960 - 2003 ALL 7.4L 454 COMPRESSED VOLUME: 9.7CC, NOM.COMP.THICKNESS .039", GEN V & VI ENGS EFI ONLY
If anyone has ever put Gen 5 Heads on a Gen 4 block what gasket did you us or is required to do so?? thanks KC:

[SoggyJet]

I have not tried the Gen V heads on a MK IV block, but do know that the issue is the large odd shape water passage used near the lifter valley on the Gen V/VI engines. I have heard that if you use the right gasket you will be okay. Check out the water passages and see how close they are. If you don't get much sealing margin I would say that it is not worth the gamble.
Doug

[Nucking futs]

Well if all the new bowtie blocks are gen 6 and all the after market heads are mark 4 then they must work.I have a set of pro topline heads on a gen 6 block and i used felfro 1047 head gasket and have not had a problem.That was my concern when i bought the new heads was all the horror stories i heard about mark 4 on gen 6 leaking and not sealing.The newer style heads will work with the gaskets but im not sure about the stock mk 4 gm heads.But everyone i talked to said they have done it on a 95% sucess rate.
edit: i miss read the post i thought it said mk 4 heads on a gen v block.that would work but not the other way around.

[Infomaniac]

Gen IV will go on V and VI. Will not the other way around.
As mentioned Gen IV has small water passages. Gen V and VI have large water passages. Gen V and VI changed the shape of the block at the lifter valley.
Can put small on large but cannot put large on small.
Clear as mud?

[Petrofied]

[QUOTE]Originally posted by Nucking futs I have a set of pro topline heads. N/F heard a rumor Pro-topline went bankrupt chapter 13. I had a chance to buy those heads dirt cheeeeeeap. Not bad horsepower makers for the dollar. Any truth to the rumor?
MR.P. :(

[Nucking futs]

I heard that same rumor,but when i bought mine they said all the heads were stuck in customs for not paying import taxes or something.The heads come from new zealand .I have seen them on the dyno sheets and they made more hp out of the box than ported merlins and some others.I decided not to run them on this engine and am building a blown injected deal for next year so i can keep up with all you fast swtd guys.If i could ever find a sw hull that i like it will go in that.So i cant tell you if they work or not yet but from what i hear they are alot of head for the money.i got them for 1400 bucks set up with inconal valves and stage 2 port job and they look great.We might put them on fourq's boat and see what that will do but i think he will be scared enough of the boat as it sits..........Tim