Posted by Chris Case [108.247.147.90] on Tuesday, November 10, 2015 at 10:49:03 :
In Reply to: Re: M37CDN, 251s, and Unleaded Gas posted by Greg Coffin [67.176.56.44] on Tuesday, November 10, 2015 at 00:03:24 :
Initially they used zinc, but that is bad on cats. Latest formula is something a bit exotic- boron maybe?
Anyway, a flattie has about 40# of tappet load, vs modern OHV, 100#, what with rocker ratios. So they finally went to roller tappets.