Quote:

Lewtot, yes there was a chevy in the '70s that used the plug. I had one and said I did in my first post. 3/8, tapered seat, short reach, 5/8" plug wrench.

Autolite 25 is one of those plugs. AC CR43TS is another, one I could find a jpeg for.

Before I posted I went to Rockauto and looked it up. Where did you get your information?

R.

thanks for the info. i remember back in the day when chevy started making angle plug heads for small blocks. i worked on a set of them, decades ago. thought they used a small 5/8" hex plug. not sure about the 5/8" reach.

my concern was putting a 3/4" reach plug (big block chevy) in a head designed for 3/8" reach and maybe a plug to piston collision.