Does anyone know what the maximum valve spring diameter is that will work on a stock 1972 455? I measure roughly 1.41" on the stock valve spring. I was looking a comp cam that listed a 1.494" valve spring in the kit. Looks like there is some space for slightly bigger springs, but I don't have the heads off, or a valve spring compressor yet (can't get a good measure on the counter bore that the spring sits in)....

Anyone else use a Comp Cams Xtreme Energy XE262H cam 218 (.475) intake and 224 (.480) exhaust. The "CamQuest6" software listed it as a 'great choice' for a High torque, Good economy, idle and overall performance. Street car - power steering and brakes. Stock G heads. 1 3/4" headers, Edelbrock intake..... Decent street cam in your opinoins?

 

A 1.540 spring is about as big as you can stick in there, more than you should ever need in those heads. No worries. Get corresponding retainers for the springs you do order. A 1.44 diameter spring/retainer package should suffice nicely, as long as it can hold 110# on the seat. I think the stock flat retainers are 1.37 dia, they do not have an inner step for an inner spring. Ditch the rotators.
I don't think you would be doing any wrong with that cam. There may be better sticks for what you want, but not by much. I have not run this cam, but it has decent lift for the duration.
JMHO
Jim