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Redline for 428 CJ?
I just bought a used Everett Morrison w/ 428 CJ and the owner had no idea what the redline is. It also came with a stripped distibutor bolt so the timing was extremely retarted. We advanced the timing and the car now runs much better and can idle around 900 when warm. I see timing recommendations for 10 idle/36@3200.
My engine has Edelbrock heads, crowler cam (300dg/577 lift intake / 310dg/591 exhaust), internal balancing, adjustable rocker arms, holley 750dp, MSI 6al ignition, 4V aluminum intake. The car seems to drive quite well now, but I haven't taken it above 5K. It does guzzle gas (9mpg at best) and pollutes unbelievably (CA SPCN exemption complete), but is otherwise a blast :) |
A few differnt things determine the max rpm a motor can see. One is how much RPM can the shortbolck handle before it lets go, this is determined by what quality parts you have for crank, rods, pistons, fasteners and bearings. The usual rpm limiter is the valvetrain. The valves will float and power will drop substantially. Revving it to a high rpm is only faster if your cam is ground to make power at high rpm. Not to mention the heads, manifold, carb etc have to be in a configuration to optimise high rpm flow rates. Your combo should be fine to 6000, reving it higher will probubly not make you any more HP. as it will probubly be falling off by then.
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Richmond Hi Take your car to a chassic dyno and have it dynoed. Find out there the H.P. tops out at and add 1000 rpm to that number. That is a safe limit for your motor. You can float your valve train at 6000-7000 rpm, but you will be hurting the motor. I have a 5800 chip in my 6al box. When the motor was dynoed it was run to 6000 rpm. Themotor only had 2 hours of running time on it and didn't want to hurt anything. Your cam and compression pretty much tell you where the power is. Mine is 2200 to 5000 rpm. The choise is up to you, I work hard for my paycheck and it took 7 years to build, if you have deep pockets, 8000 rpm should just about do it. Your machist will love you. ;) Rick Lake
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Yea. 8k:LOL: take it up to 6k.. see if it noses over (the hp curve) If it is strong try 7k.. I would limit my fun to below 6500 unless you are confident in your build. Roller valve train will help. The very least you might try a good roller rocker arm set up. You mention adjustable lifters but you didn't say it was a solid lifter engine.. That will make all the difference at 6300+ rpm. Beyond 6300-6500 you really should give the mains some support, either a girdle ala the 385 series engines or cross bolting ala the 427's.
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The specs on my engine say the previous owner paid extra for "shell type light weight lifters" which sounds like they are not rollers. 6000-6500 sounds fine to me, though now I blew out pert of a header gasket and have to get that fixed first...
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I have a very similar setup in my 428cj. After 9000 miles of very
hard driving I've managed to blow an 11" clutch, twist 2 sets of axles, rip the teeth off my spider gears in the Jag rearend and wear out one set of rear tires drag racing and doing burnouts. Yea I broke a lot of stuff but had lots of fun. Back to your question about rev limit on your cj motor. With my setup I was able to use 6400rpm and use it I did. Rev-limiters really do work and are a must if you drive hard. If the bottom end has cj rods or better they can handle mid sixes without letting go. As for timing most cj info I've read recommend 36 to 38 degrees total advance. Sounds like your carb primaries need adjusting and or possibly your power valve is dumping fuel. Good luck. |
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