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  #1 (permalink)  
Old 10-29-2020, 05:33 PM
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Default balancing 351w

I've been a bowtie guy since the early eighties and am putting together my first SBF from long block with all new parts. I've picked up a new stock 28oz harmonic balancer for it.

My car is an early '90s built '69 block 351w with a toploader. I'm kicking around the idea of an aluminum flywheel.

My replacement is a '94 truck block running a flat tappet cam.

I haven't had my engine pulled yet. I don't know what else is under it. I spun a bearing a couple of months ago and want to basically start all over with everything engine related.

If I have a 28oz harmonic balancer, do I need 28oz weights on the flywheel?
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  #2 (permalink)  
Old 10-29-2020, 05:47 PM
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If I have a 28oz harmonic balancer, do I need 28oz weights on the flywheel?
Absolutely. The harmonic balancer and the flywheel/flexplate must much.
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Old 10-29-2020, 08:40 PM
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Most likely the flywheel will come equipped with a bolt on weight for the counter balance. If your building the engine with all new stuff and going to have it balanced--you could have heavy medal inserted just in the flywheel end of the crank for a neutral balance back there and then you could use a flywheel that was neutral balaned-this method works good for conditions where the clutch /flywheel gets lots of replacing such as in race cars

Last edited by Jerry Clayton; 10-29-2020 at 08:44 PM..
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Old 10-30-2020, 01:31 AM
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What oz off balance depends on what the crank was balanced to be.

If you are starting over with a fresh rebuild, and you can afford the cost, have the rotating assemble balanced to 0 off set externally. In other word, have it internally balanced. Then use a 0 offset or balanced harmonic dampener and flywheel.
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Old 10-30-2020, 10:33 AM
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I built up a 351 last year. Selected all the parts to match then took to a machine shop and had all the components weight matched and balanced. Costs a couple of hundred dollars but well worth it in the end.
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Old 10-30-2020, 04:13 PM
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Thanks, all.
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