Hello First time poster, long time GMC Lover. I have looked in past post for the information I'm looking for,no luck, so please bear with me.
I have a 1977 GMC K25 Sierra Grande, Regular cab, Long bed, with a SB 400 and TH350 and a transplanted NP205. The guage cluster has large fuel guage and a mechanical oil pressure guage. I just picked up dash that has a Tachometer to the right of the speedo and electronic oil pressure guage. This is a factory unit, no cutting on back of cluster to fit tach. Does any have a wiring diagram for the back of the tach cluster and for the large fuel guage cluster? Also know where to move the wires to make the tach cluster work in my 77. The tach is not big deal, have installed tachs, and have seen the writing on the back of the tach its self. Any information would be geat.
Thanks
Joel