Pro Comp heads are installed.

Thanks for the response. No need to measure, I know which ones you are referring to and have the same ones on the shelf. I am still debating using the Procomp rollers vs set of of old 273 adjustables I have. Sounds like the Procomps may be a much bigger pain to deal with when the 273`s may just bolt right up.

Another problem I have already ran into is that I will need to hog out the intake a bit for clearance as the carb butterfly can not open all the way. Did you zsee this problem too or just use a spacer under the carb?