George,
One question, are the speed pro pistons domes? If they are they won't work with the chamber in the vortec heads and the compression would be sky high (aprox 64 cc chambers). If you have flat tops and a cam with 230 @.050 or more duration, and you keep the total timing around 30 deg total you can usually run 91-93 octane gas. I like to look for cranking compression in the under 190 psi range to run on pump gas. I hate to make this complicated but it all has to work together.
Sean
