Tach Question

[Paul Schooley]

Greetings all,

I'm curious. What should the correct redline be for a 2.7 engine (circa '77 - S cams with mildly ported heads and Webers)? I'm running the original tach in my 71 and, although I know it's not redline, the engine 'feels' like 5000 on the 71 tach is the sweet spot. The problem I'm having is not being clear on whether or not my 71 tach is calling it like it really is or if the engine's rpms are higher than the tach is showing.

Signed...confused in Canada

[ttweed]

The problem I'm having is not being clear on whether or not my 71 tach is calling it like it really is or if the engine's rpms are higher than the tach is showing.

Paul-
What makes you think the tach is not indicating correct RPMs? 5,000RPM may feel sweet as it could be your torque peak, depending on the setup on the Webers, but the engine with S cams should be able to rev to 7,000-7300 safely. Your tach should be getting the signal from your CD box, and there's not much to go wrong there.

TT