Offshoreonly.com - approximate horsepower!

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Those cam numbers are strange. Lots of duration and and not that much lift. Not a very good cam selection, especially with the 110 lob sep. Probably making about 380hp at 5000rpms.

Wow, you guys are killing me here! The builder has a great reputation and has re-built many "blue motors" here in the Louisville area. I was planning on changing the exhaust to something like Stainless Marine but as of right now, the motor may have about 6-8 hours on it since it was rebuilt. I have checked the oil after every trip and so far no "milkshake"! I will check the cam card again to make sure I gave you guys the right specs. I believe I bought it the cam, intake and carb from CP Performance a few years back.

Quote:

Originally Posted by gofastwannabe (Post 3367994)

Hey all you engine guru's, I have a question for you. I had my engine rebuilt year before last by a mercruiser master mechanic. It's was a Mark IV 330 HP 454and I upgrade to 461 CI with speedpro coated hyperutectic pistons, Isky flat tappet cam with 230 intake and 236 exhaust @.050 with 515 lift on 110 lobe separation angle. It is topped off with Edelbrock RPM oval port aluminum intake and edelbrock 750 cfm marine carb with GM large oval port heads, (230cc I think) with stock valves. It also has crane roller rocker arms and us still using the stock exhaust straight out the transom. I know it's not a race motor and I don't treat it like that but I was just courious about how much HP it may have if I go to sell it in a year or two.

Did you edit your original cam specs? Because I could have swore i saw ultradyne, with like 236/[email protected] on 110* orginally...????? Unless my mind is going, which it surely can be..

Quote:

Originally Posted by MILD THUNDER (Post 3368804)

Did you edit your original cam specs? Because I could have swore i saw ultradyne, with like 236/[email protected] on 110* orginally...????? Unless my mind is going, which it surely can be..

GPM posted the ultradyne specs.

Quote:

Originally Posted by gofastwannabe (Post 3368784)

Just trying to be honest, I blew mine up from reversion several years ago. I was using a crane cam with similar duration specs and more lift and 112 LSA. I trashed my oil, spun berrings and broke a crank. I had moisture under the valve covers, lifter valley and behind the timing chain.

At this point, i'd try to get a nice set of stainless marine, gil, imco, EMI, or similar manifolds with extended risers. The exhaust will let them breath, and help eliminate reversion chances.

I do like the oval port setup for what you have.

Quote:

Originally Posted by gofastwannabe (Post 3368784)

Im in the Ray camp on this one from personal experience

I wouldnt think you'd have that much problem with that setup, but you would really "wake it up" with any good aftermarket exhaust system. Id say that setup on a dyno with headers would probably make about 420 HP.

I ran an engle flat tappett cam with a 110 lobe sep in my 500 hp small block for years with no ill effects and in some ways the loss of valve control at higher rpm kept me from blowing it up as I came out of the water when I was a "punk kid".

Get yourself a good set of headers or at the very least a quality manifold with as high of a riser as you can fit under the hatch and just run it.

Uncle Dave

I would like to see the rest of the numbers on that cam, I don't know that the .050 numbers on a cam that size would have as much affect on reversion as seat timimg. I agree with the exhaust change for better power.

Hey guru"s, will the EMI Thunder system work with the 3" taller risers? My stock cast manifolds have the 3" spacers on them now so that's why I ask. They go straight out the transom and have an old set of Gil tips that don't work anymore them and I keep them closed most of the time. $2150 seems to be a reasonable price for this.