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Author Topic:   how much RPM w/cast assembly
Dirt Maniac

Total posts: 138
posted February 20, 2002 09:22 PM
Can I turn a 383 W/scat crank, eagle sir & hypers 68 to 7200 and expect it to last?? 12 to 13to1 comp, 4 bolt block, on gas.

Dirt Freak

Total posts: 310
posted February 20, 2002 09:30 PM
I never like to turn cast over about 6500 and only with good machine work and balancing that might be on the upper limits at 7200 but I'm sure that other people will know more than I

Dirt Freak

Total posts: 499
posted February 20, 2002 10:39 PM UIN: 23443678
I have run lots of cast stuff including pistons. We never had a problem with em but we keep it around the 6700 rpm range. I just got a cast crank back that was cracked but had 3 years of hard racing on it 2 in a stock car on gas and 1 in allky mod. Like the above post if its balanced right and the clearances are right and you keep the rpm below 7000 for the part it should last. We ran a cast 383 motor over 30 races with not a problem sold it to be raced some more(block was full of concrete)but ran it around the 6800 rpm range Hope it helps.

Dirt Full Roller

Total posts: 73
posted February 22, 2002 01:22 AM
Our first year in modified racing we ran a motor with a cast factory GM crank, X-rods, and cheap cheap hyperutectic pistons, ran all over the 7200rev limiter, and never broke a thing, so yes in my opinion you can.

Dirt Forum Racer

Total posts: 96
posted March 01, 2002 10:29 PM
I say ya it will be ok Ive ran cast cranks befor and had no problems, the track champ this year at my track says he would not run a steel crank if you gave him one , he says they are they are none forgiving, says cast cranks flex a little and are not as likly to break.

Dirt Freak

Total posts: 220
posted March 02, 2002 08:02 AM
I think it all depends in how much horsepower you are running over 500 to 550 i have been told they would brake.

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