[SD455DJ]

I’ve used stock small valve 1970 #15 heads on a YH 455 build that made 390 hp through log exhaust manifolds, stock cast iron intake & q-jet carb. It has a Summit 2802 cam. We had the press-in rocker studs pinned rather than converting to screw-in studs. They have been fine for 5 years of street use with no pull-out issues. The valve springs have 120 lbs. seat pressure and 270-280 lbs. at full lift (.466”/.488”), so relatively soft. After a minimal cutting to true up the deck surface the chambers measured 90-91 cc’s and 9.94 to 1 compression on the .040” over 455 (464). We used Ferrera 1-piece stainless steel street valves (1.96”/1.66”).

The stock small valve heads flow around 195/150 cfm at .450” lift that the 2802 cam provides. It’s an easy 400 hp/520 lb.-ft. engine with RA manifolds, a little more with headers. I believe Stan has various 1970 #15 heads on his head flow list that had 2.11”/1.77” valves installed that flowed as much as any other stock large valve head of the time (12, 13, 16, 62, 64, etc.) around 210/160 cfm.

Rocky Rotella wrote an article for HPP magazine years ago flow testing stock 455 #15 heads and then again after converting to 2.11” and 1.77” valves. I believe these are on Stan’s list.

I think these are good heads to keep/sell/reuse/convert to large valves.

Dennis

[sdbob]

My self I keep 6x heads. 4x s I'd pitch.