7.4L and merlin heads
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7.4L and merlin heads
i have a mark IV motor and i am thinking of buying these merlin heads from someone. will they work on this engine? i just dont want to buy something that wont fit i have herd that some heads wont fit some blocks and will leak water. i dont know if this just applies to gm heads? and not aftermarket?
Last edited by 98itrwhite; 09-16-2005 at 07:25 AM.
#2
Re: 7.4L and merlin heads
Most aftermarket heads are designed to fit either block. I have a pair of Merlins on my Gen VI engine. World Products say their Merlin heads will work on Mark IV or Gen VI blocks.
The stock head bolts will not work on Merlin heads. I bought a set of ARP bolts for mine. I think they were about $100.
The stock head bolts will not work on Merlin heads. I bought a set of ARP bolts for mine. I think they were about $100.
#4
Re: 7.4L and merlin heads
Originally Posted by 98itrwhite
is there a special gasket set? or just a mark IV gasket set will be fine?
#5
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Re: 7.4L and merlin heads
You need the ARP head bolts and Feel Pro gaskets for the Mark IV block. Check the gaskets on the block first but they should work fine. The good gasket retail at around $100 per set but they are worth it if you run in salt. Are these the raised exhaust port heads?
We just built up a pair of 496 strokers with the Merlin heads. They scream and make for a pretty reliable set up.
If you need the PN for the gaskets let me know, I'll look it up.
Fionn
We just built up a pair of 496 strokers with the Merlin heads. They scream and make for a pretty reliable set up.
If you need the PN for the gaskets let me know, I'll look it up.
Fionn
#7
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Re: 7.4L and merlin heads
The heads will fit, but if your engine is a 330HP 454 with flat tops (8:1 compression and wimpy cam), you may not gain a whole lot without making other changes...
With 9:1 compression and a bigger cam, you can gain 100HP with those heads...
With 9:1 compression and a bigger cam, you can gain 100HP with those heads...
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Patrick
Patrick
#8
Re: 7.4L and merlin heads
Think COMBINATION!! Heads, intake, cam, carb {or re-jetting}, maybe pistons for more compression...........on and on and on.....
Don't buy a part here and a part there just because ya get a good deal on one. Discuss your hp/tq/goals with someone who knows their chitt ...rmbuilder, cstraub, Mesa, just to mention a few here on OSO. You'll be much better off and save allot of BS down the road. Just my .02
Don't buy a part here and a part there just because ya get a good deal on one. Discuss your hp/tq/goals with someone who knows their chitt ...rmbuilder, cstraub, Mesa, just to mention a few here on OSO. You'll be much better off and save allot of BS down the road. Just my .02
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Re: 7.4L and merlin heads
Originally Posted by Kidnova
Think COMBINATION!! Heads, intake, cam, carb {or re-jetting}, maybe pistons for more compression...........on and on and on.....
Don't buy a part here and a part there just because ya get a good deal on one. Discuss your hp/tq/goals with someone who knows their chitt ...rmbuilder, cstraub, Mesa, just to mention a few here on OSO. You'll be much better off and save allot of BS down the road. Just my .02
Don't buy a part here and a part there just because ya get a good deal on one. Discuss your hp/tq/goals with someone who knows their chitt ...rmbuilder, cstraub, Mesa, just to mention a few here on OSO. You'll be much better off and save allot of BS down the road. Just my .02
#10
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Re: 7.4L and merlin heads
It takes a little work but it's not really that difficult. Put a roller cam in it similar to the HP500 cam and prop it to turn 5200-5400. It can put out 500+ reliable horsepower.