"Strange New Vibrations"

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Feb 26, 2006 | 10:58 AM

rowdyron

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"Strange New Vibrations"

I recently swapped engines in my 1979 F-150 4x4. It had a 351M in it and I installed a 1973 351 2-barreled carb. cleveland engine. The truck has a manual 4-speed transmission and I was told that the only modifications needed was to change the bell housing. When I finally found a bellhousing (off of a 300cid 6 cylinder eng.) and started to bolt it up,I quickly noticed that it wouldn't fit over the flywheel and clutch assembly from my 351m setup (the 351c had a flex plate). I then purchased a 300 cid. 6 cylinder flywheel an installed it. After everything was bolted back together and on engine start-up I noticed strange new vibrations. I was wondering what combinations I needed to correct this situation utilizing the 300cid bellhousing. ANY HELP IN THIS MATTER WOULD BE GREATLY APPRECIATED!!!

Feb 26, 2006 | 11:07 AM

bmc69

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Holy smokes..step away from the engine!. You stuck a neutral-balance flywheel on an externally-balanced engine. We'll skip past the fact that you should get any engine reblanced as part of the build...your easy fix will be to take that 300 flywheel and the flywheel that came off the 351m and have them 'match balanced'. There will be quite a few holes get drilled in that sucker, but she will come in to spec.

Feb 26, 2006 | 11:22 AM

rowdyron

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Where would I get the flywheel match balanced? I was wondering if a flywheel off a 289,302,or another 351c would work with the bellhousing. I'm wanting the cheapest but funtional way out of this situation. HELP!!

Feb 26, 2006 | 11:34 AM

bmc69

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I missed that it was 'c' and not an 'm' that you installed the 300 flywheel on. That explains how it bolted up anyways. I don't recall off the top of my head what the imbalance for the 'c' flyweel is supposed to be..the 'w' is 28-0z. You have exceeded the extent of my knowledge on this particular combination....hopefully someone else will pipe up with an answer. I know a guy I can ask that has swapped 'c's in to a few trucks.

Feb 26, 2006 | 11:40 AM

rowdyron

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To bmc69 I appreciate you concern would definitely be greatful for any more inputs. Thanks Much!!

Feb 26, 2006 | 01:03 PM

grclark351

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From: chicago burbs

just get a 28oz flywheel. for what it'll cost to balance(if they'll do it?), the down time, and worry that it might come apart, you'll be ahead to just get the right flywheel. i'm pretty sure what you want is a 14.23" diameter, 164 tooth, 28oz flywheel. applications include early 302, 351W, 351C and maybe others. triple check the tooth count on the 6 cylinder flywheel that you have, if the starter engages(i guess it does) it's the right tooth count for the bellhousing. so i guess it's true that a 0 balance fly on a 28oz engine will shake?!

Feb 26, 2006 | 01:27 PM

bmc69

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Shake..I'd say so!. Just like indavertently using an old 28-oz flywheel and or harmonic balancer on a 50-oz '18-up 5.0 will shake. Glad someon piped up about the 'C' balance. Figgeres it would also be 28 oz but I didn't know and was too lazy to go down to the shop and look it up. 8-)