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Discussion Starter #1
Trying to piece a motor together from various parts in the garage. Want to enjoy the summer before its over and need advise on which heads to use.

Base is a Merlin 565 ci tall deck. 11-1 compression with the Brodix big duke heads (flow 456). set up for blown alcohol. Can I recam it and run in my jet boat with a single Dominator(1150), or should I put a set of Merlin/Grumpy(flow 320) heads on. The Merlin heads came from my exploded 496 ci.

Will have to replace the cam either way as it was damaged in the destructive process.

Jerry
 

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Just another Wannabe
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The big dukes will take quite a bit of RPM to really be where they like in that combo. But if your pump is set up to run that rpm, then it could be a good deal. (Most jet pumps don't like the rpm that the engine will need to make those heads work.)
On the other hand, I have run a few engines with those heads on a cubic inch rather similar, and the torque those things make down low is incredible. If your pump wants the 5600-6000 range, the merlins will make that boat scoot. And the rest of the engine will like the fact that it does not need a b-gillion rpm to work. JMO
 

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Village Idiot
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One thing that might be a big problem in the pistons may not wont to work with the merlin heads. If I were in your shoes I would probably leave that big dukes on and live with them for the time being than trying to cut the pistons for the chambers and valve reliefs. At that point you might as well start from scratch.

Anyway, that is just my opinion.

Paul
 

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Discussion Starter #4
heads

typically run 6,000 rpms n/a, and 7,200 on the bottle. This is in a 21' Daytona

What I failed to mention, is the pistons are flat top, actually about 1/8th in dish, with valve reliefs. The Brodix are 91cc chambers, and the Marlin's are 119cc. So to switch to the Merlins would drop the compression, alot.

Jerry
 

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Bostick Racing Engines
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typically run 6,000 rpms n/a, and 7,200 on the bottle. This is in a 21' Daytona

What I failed to mention, is the pistons are flat top, actually about 1/8th in dish, with valve reliefs. The Brodix are 91cc chambers, and the Marlin's are 119cc. So to switch to the Merlins would drop the compression, alot.

Jerry
Well... if the pistons are for the big dukes... and is 11:1... then the only solution is to either run that combo and be happy... or get some pistons for the merlins as that combo with the dished pistons that are 11:1 w/91cc heads would be about a 2 point loss. 9:1 alummy heads... eh... having to hack the valve reliefs to match the angle change (at least on the intake)... eh... sounds like it just wouldn't be a happy situation.
 

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Hey Jerry, Was that the twin turbo that went threw the destructive process? Sorry for the thread jack. Good luck with the spare engine.
Be safe. schick
 

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steelcomp was here
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Hey Jerry, Was that the twin turbo that went threw the destructive process? Sorry for the thread jack. Good luck with the spare engine.
Be safe. schick
Re-cam it and run it. Nice thing about jets is they're pretty forgiving of heads that might be a little big, and you've got a bunch of cubes there...might be surprised at how good it'll run, just don't port the intake. ;)
 
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