My new to me 32 has a 401 without a tach. I have a vintage SW mechanical tach that I hope to utilize. I know that 5k is low but not racing either. What are the options?
Probably a couple of ways to drive it on your car. A vintage Mallory dual point with a tach drive or an early corvette generator with a tach drive. if you choose the gen you will have to match the lower pulley size of the corvette so it is reasonably accurate. Tachs that are driven from a dist are a different ratio than gen driven tachs. If you choose to use the vette generator your tach will read double actual rpms. they can be recalibrated or you can get a gear reduction (.500) to put in the cable
I'm thinking about doing the same to my 322 nailhead. I have the tach driven DELCO generator with the gear housing that attaches on the back. What modifications do I need in using a mechanical tach with a 2 to 1 ratio.
just as I stated in the message you quoted, either you need a 1:1 tach or a .500 gear reducer in the cable. similar to this https://www.ebay.com/itm/1262437353...hmX+7mHd6H0SVCV05L6INETg==|tkp:Bk9SR7aCo-LQYw
I've compared the pulleys. Both crank and fan blade pulleys on the small block are slightly larger in diameter. Wouldn't both pulleys on the nailhead have to be changed?
Nailhead pulleys are very specific to that engine with limited sizes available. Better to look at the generator pulley size to get the rpm needed.
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