Midyear BB harmonic balancer bolt headmarks

[Steven S.]

Hi guys, wondering what variety of headmarks have been seen used on the big block cars 65-67?

Thanks,
Steve

[Gene M.]

Re: Midyear BB harmonic balancer bolt headmarks

Hi guys, wondering what variety of headmarks have been seen used on the big block cars 65-67?

Thanks,
Steve

Steve,
My collection of original GRADE 8 crank bolts for BB & SB has TR, M. There may be others but too cold to go out and have a look see.

[Steven S.]

Re: Midyear BB harmonic balancer bolt headmarks

Thanks Gene,
I can appreciate that, 8 degrees here in PA and a lot of wind, -13 with wind chill they say.

Steve

[Wayne M.]

Re: Midyear BB harmonic balancer bolt headmarks

My mid-May '65 961 (396) block with the "6223" cast # crank has an "FC" headmark bolt with the 5 radial lines.