TAC Tech => Electrical => Topic started by: tmd171 on January 16, 2022, 08:33:10 AM

Title: HEI tach help
Post by: tmd171 on January 16, 2022, 08:33:10 AM

Does anybody know if an HEI tach can work with a points distributor?

Title: Re: HEI tach help
Post by: 5th T/A on January 16, 2022, 09:59:25 AM

Are you referring to a GM factory tach?

I believe Firebirds used the same tach in 73-75. 1973 would have been a points distributor while 1975 came standard with HEI.

Title: Re: HEI tach help
Post by: chief poncho on January 19, 2022, 02:04:43 PM

Yes it should work fine.  I ran an HEI on my '71 with an original '71 Tach with no issue.  Just hook up the tach wire that normally goes to the coil to the tach output from the distributor. 

(https://cimg9.ibsrv.net/gimg/www.thirdgen.org-vbulletin/533x399/174c2d83_3461_459f_b417_73692c6ca361_eff695dd31d89d211f8a6b69e9aa82558b69bd0b.jpeg)

Title: Re: HEI tach help
Post by: chief poncho on January 19, 2022, 02:33:36 PM

Whoops, just reread the original post.  You're asking the opposite question, will an HEI tach work with a point's distributor, I just answered that a points tach would work with an HEI distributor.

To answer the question, I believe the answer is the same.  Just run the wire that normally goes to the Tach output of the HEI to the negative terminal of the coil.  It should be a two wire tach and the other line should run to a 12V source when the key is on.