Cat & Mice

A guy I know had a big 600++ CU motor in his 30 foot V. He was not happy and ended up with a HP500 W/Whipple. He is super happy and has had no problems.

He thought the NA big cubic inch did feel fast and was a dog.

Just someone's experiance.


Mike

burtandnancy

I got a chance to test drive Fred Inman's test mule with a single 708 (out of the mid-west I believe). Impressive torque for an NA motor. If I remember correctly it only ran about 5400 or so rpm...

Ratchet

Might as well go with the 700 CI then - lol

The only issue will be the fact that you need a supertalldeck 11.625 block, and an oddball crank (cause of the bore spacing)

Actually, that's a pretty heavy combo, and I don't know if it would fit if you didn't have staggered engines. Heck that big you may beed big chiefs, or big brodies to flow enough......that just adds to the problem.

Oh well........you can always dream big

jdnca1

I run a 632" Merlin in my Carrera cat. 4.75" stroke / 4.60 bore. The only real issues I've had have been valvetrain related. (You have to run big duration and big lift to really make the power NA)

The motor makes 820 Ft/# of TQ at 5000 and 900HP at 6700 on 93 octane. 10.5:1 CR on tunnel ram with fully ported Dart 360 heads. After a couple of lifter failures I've gone to the Schubeck "radius lifters" in hopes of more durability. (basically a solid flat tappet that is "radiused" to run on a roller cam lobe) The jury is still out on these but I hear Comp Cams is in heavy development of their own design and Pro stock cars will be running them next year.

What you're friends are saying is basically true, bigger is better (to a point) 632" is about as big as you can practically go without getting into basically custom made parts. I would start with a 622" (4.56" bore) to leave room for addnl bores if they're ever needed.

If you want I can give you a run-down on the major parts in my motor and dyno sheets, I don't know where you live but around here you can duplicate my motor for around $18k using all high end parts.

Steet

MakDaddy, I can relate to your situation. I bought a new boat on October 24th and ran in the Sarasota poker run on Oct. 26th and the boat now has 10 hrs on it and going into hibernation. When it awakens in the spring, I will have 2 new whipple EFI's awaiting the new 500's. I will probably run it another 10 or 20 hrs. before surgery. As far as the large cubes, I believe it is better to use the whipples w/intercoolers, and run about 5 lbs of boost which should deliver about 650 to 675, very reliable horsepower on pump gas. I have friends who have the whipples with no problems and making outrageous horsepower. The quad rotor on a 540 is making over 1000 horsepower with racing fuel. Outstanding

Steet

Catmando, If only I had a magic lamp. That power would be awesome in any boat and twins is even better. I bought a 390 Velocity.

Ratchet

Cool............pump or race gas ?

Mr Gadgets

Lets see, 565" on a 4.25" crank, 4.600 bore, .025" left. Custom pistons anyway.. Merlin block measures out at 11.665" deck. Very long rods! Flat tappet cam, .904 Shubeck lifters. Jury is still out! The drive had major drag due to broken bearing wedged beteen race and lower pinion gear. Going to outdrive school now! Next summer maybe! And maybe a set of those big chiefs!!

Dick

KAAMA

Ambusher,

You're going to hear a lot of opinions here, but I'm not so sure I would limit my search to an IMCO SC drive. I was thinking of the IMCO SC's myself, but lately I haven't always heard of good things with these IMCO SC's. I've been looking into a couple other drive shops that I have heard about and you might want to check them out as well. BilletMarine.com and MaxMachineWorx.com are two other companies that I would check before settling on IMCO. Right now Billet Marine has a modified Bravo One drive that is supposed to handle 1400hp and Max Machine Worx has one that is close to that figure as well. Just throwing out more options. I would say at least check them out first before making a decision on whose drive to buy. Just my .02

BTW, love your avitar---how true it is!

Ratchet

Mr Gadgets................the block you're referring to is a "super tall deck"

Typical Blockls are 9.800, or 10.200 (tall deck)