Confession time. My first car was a pretty used up 1970 FJ40. Convertible specs as i later found out.
As a young motorhead, i knew the thing needed a small block chevy.
I had ditched the column shift with the help of a neighbor that had a couple of 40’s in his back yard. Very cool guy I am still friends with 40 years later. Him and his girl “total hippies”. Usual greeting was “wanna bong hit?”. I was 16, it was 1983, you do the math.
So I had stepped up to floor shift 3 speed, a holley 2300, and had a plate swap kit and mounts and more good chevy stuff than I could store at home. All that was left was to toss a rod in the F engine and create the need.
I didn’t change the oil for about 20,000 miles, and used the tach hitting 4 grand as a shift indicator, every gear, every time.
It just kept running better.
I sold my poor abused baby in 1992. It had been run hard, mistreated, and had stories to tell from before I owned it. It never let me down in any big way, and I sold it with the F engine still in it and 8 year old oil with lots of miles on it.
Still ran great. Maybe better than current rig with efi, h55, ps, etc. Maybe just nostalgia.
Either way, tach was just there to say shift at 4000 (screaming in F or 2F). You probably have better sense than doing what I did, but if not, know that 4000 rpm should make you think shift! Even without a tach.
