You'll be soooo much further ahead of the game by going with the vortecs.
Don;t bother with used vortecs. Buy new "12558060" assemblies.
Pick a cam with less than 465 lift and bolt them on without modification.
Especially if you already have a vortec manifold to use.
The Summit 1103 cam you suggested will make not less than 375 dyno HP and in excess of 400ft/lbs. on a flat top piston 350 motor.
Another good mild choice is isky #201264
Its also a bolt in with stock GM vortec heads.
If you want 400hp substitute this power full Isky .450" lift rule cam #201278.
All it needs is a set of Isky 205D hi perf springs minus the inner damper to replace the stock GM springs and you're good to go. Degree it in on a 102 intake C/L. Needs a high stall converter and agressive spark advance curve for best results. Be ware of excessive fun with this combo.
All will work just fine with stock GM 87 up self guided rocker arms.
The modest .450" valve lift of these Isky cams allows you to get the performance you want from OEM vortecs without further costly valvetrain modification and machineing.
Last edited by F-BIRD'88; 09-18-2008 at 08:21 PM.