Jumping in late, but +1 to the others who mentioned spending time dialing in your combo before throwing more parts at it. The combo is solid on paper. My bet is your issues are likely a combo of small things that need to be tweaked - fuel mixture, timing curve, maybe cam advance. I like the suggestion of chassis dyno time to get a baseline.
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Ken
'68 GTO - 464 - Ram Air II heads - 236/242 roller - 9.5” TSP converter - Moser 3.55 Truetrac ( build thread | walk around)
'74 Ventura 350
'69 AMC Javelin SST
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