I know this has been covered before but indulge me if possible.

Can you put World Products Gen IV Grumpy Jenkins heads on a Gen VI block?


If so are there are pitfalls? What is the best head gasket?




The heads are stock do they more or less power than the Gen VI heads?

Thanks in advance
Steve

Yes, you can put any head (aftermarket Mk IV style, Gen V and VI) on a Gen VI block. Use Fel Pro 17048 for 4.530 bore or less.
Eddie

Thanks Eddie! Any thoughts on output? This is a mutt was a fresh engine Stock hp 500 carb .030 over with full length CMI headers. The headers leaked and rusted up some valves. Would you redo the Gen VI stuff or use the Merlins?
Thanks
Steve

Eddie, Any reason why you wouldn't use Cometic's MLS

They work fine, go with the merlin heads they will out flow any factory GM head.
I used the felpro mls gaskets when I put merlin heads on my gen 6 block.

That sucks man. It really depends on what you are trying to do. If you are going to keep it at a 510 or 516 (.060 over) and not try to make gobs of power than the Gen VI heads are a pretty good choice. They are actually a pretty good head with just a little work. It also depends on which Merlin heads you have. If they are up around 340-345 cc than they will be a little big for a smaller inch engine. They would work better with a 540+ ci. If they are 315-325 cc, then they will work well with the 510-516 ci.
Are the Grumpy heads cast iron or alum? I'm not that familiar with their stuff. With either cast iron head and 510-516 ci you could make 575-600hp with some port work, decent size cam and a little more compression than the stock 8.75:1. If they Grumpy heads are aluminum, then with a 510-516 ci you could easily make over 600 hp. Hope this helps.
Eddie

No reason at all. I use them on a regular basis and love them. However, on the NA engines I stick with the Fel Pro's unless I need a thicker or thinner gasket then .040 to juggle the comp. ratio. On the SC stuff, I won't use anything other than the Cometics. I only use the Fel Pro's to keep the cost down. I take them on an engine to engine basis. If I think it needs a Cometic, I will put it on no matter what the cost. Normally, an NA engine around 600 hp will do just fine with a Fel Pro.
Eddie

Thanks guys
Steve