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I just bought a 24 hallet :) I've got a low hour GM crate 502 that's going in to replace the tired 454 mag. It's an older crate motor (not the 502/502) that has a hydrualic flat tappet cam: duration (@ .050"), is 220/220, max lift is .500/.500. The heads are GM rectangular port w/ 2.19/1.88 valves. Right now the motor has an 850dp, the GM hi-rise dual plane, & imco headers exiting above the waterline. The motor was advertised as 440hp & 515lb/ft. Would there be much to gain with another cam, would a victor jr. type intake kill my low end too much? If you've got a 24 hallet with a similar 502 I'd love to hear what kind of numbers you're getting or what mods seemed to pay off.
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That is the stock marine camshaft you have there (comes in the crate engines as well). Use an aftermarket camshaft with 224/230 intake and exhaust duration on 110 degree centerlines and you will see a dramatic improvement in performance. Keep the stock GM marine intake manifold for best performance at 5200 rpm.
Sincerely
Dennis Moore
www.mooreperformance.org
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224/ 230 is nice, but do it on 112 centers. Install it at 109 and it will pull all the way up into the low 5's. 112 holds more cylinder pressure and flattens the TORQUE curve. TORQUE moves the load, not horsepower. Don't think about horsepower until your motor runs over 5200 RPMs. 110 makes PEAK DYNO #s, but torque moves the load, you need it to PULL up to 5k not lay in the 3500/ 4500 zone for days! If you advance the 110 cam enough to make it PULL, it will run out in the high 4's Good luck and let us know what happens. eek!
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I've got a complete cam kit hyd. roller for you. Its a little bigger than the one dennis sugested.
It has about 4 hrs on it.
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Thanks for the ideas, I'll let you know what I decided to do & the results. For now, I'm gonna finish out the season, I'll make it a winter project.
