looking to find out what would be good cam for my 1974 corvett 350 four bolt main
Picking a cam for your Vette will take some research. First you have to know what improvements you are looking for, beyond the awesome loping sound it will make through your exhaust. I would go to the various cam web sites to get their advise - call them even. Talk about you goals and expectation, how you drive it, etc. and I'm sure they can help. They are very complicated, varying lift and duration of the intake and exhaust valves. Another option would be to go to your local, reputable speed/tuning shop and get their opinion. Sounds like a fun project.
I built my 1969 Corvette's engine using a 400 crank, bored out 0.040 and used a top output cam. On the second rebuild due to internal part failure, it was correctly blueprinted and found there is 0.001" clearance between my pistons and the intake valve fully opened. I had to have a special cam made to lower it to 0.003. I lost 10 hp but may save and engine if I miss a shift. So make sure your engine can take the cam you chose. My pistons were flat top and didn't have the dimples to allow for further valve openings. You will lose compression with those other pistons, so like ipson said, do the research, look and ask.
Search Chevrolet Corvette Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
Chevrolet Corvette Experts