[Ed Wright]

Some of the rules listed are wrong.
A, B & C were lbs/cubic inch.
Seems like a was 8.5 lbs, B was 9.5 lbs and C was 10.5 lbs.

A/SM did not have to be a big block. I took a shot at it with a 400" sbc.

B/SM did not have to be canted valve engines, still lbs/cubic inch. Lots of 331" sbc there.

C/SM was allowed canted valves one year. Fadley won C/SM at Indy that year but was bounced due to a displacement error. His crank was not what he ordered and he failed to measure it. Something like one cubic inch big at tear down. Voglen should have won. Fadley took him out early. I was dead late in the class semis, and an eleven second car ended up winner when Fadley was tossed. Rick Voglin was robbed. Next year C/SM was inline valves only. Seemed like C/SM had like 30 or so cars at Indy that year?

IHRA had Super Mod as a heads up eliminator at 10 lbs. Looser head rules, 11.5" tires and 850 carbs instead of NHRA's 750 cfm, 10.5" tire rules. Any GM head castings allowed. Rickey Smith pretty much ruled there.

NHRA allowed certain number 750 cfm carbs, pretty much same as SS rules there, but the choke butterfly & shaft could be removed.

Cylinder heads had to be assembly line available castings, no "Bowtie", "Turbo", etc. Porting allowed was chambers, and 1" below the bottom of the valve seats in the bowls, and 1/2" back from the intake flange for port matching. Any valve size.
There was a difference in heads. I had four sets from big name shops doing Modified heads. Won't name them all, but Lee Shepherd's were nearly a tenth quicker than anybody else's. They showed much better on my flow bench too. Shows how criticle the valve job & seat/bowl area is.

Btw, the Fadley & Mike Edwards car is one and the same.