090 or 993 are the casting numbers you're looking for. They were used on both 360s and 401s from late 71 thru 73.

You can modify your bridged heads by having the rocker bosses milled about .375", having the holes drilled/tapped to 7/16". You have to use guide plates and hardened pushrods. Harland-Sharp makes a set of roller rockers that bolt on bridged heads without machining. Either way, cost is about the same.

Bob
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