Ya it was running great before I take it out and I’ve got a preformer 350 olds edelbrock intake with a Holley sniper on top and do you think I would need new pistons with this kit?
If the engine runs OK, doesn't make any strange noises, doesn't burn oil or or dump coolant into the oil pan and you plan ti just drive it you likely do not need to rebuild it.
A mild cam and head swap will work wonders, and get you the most bang for the buck.
-#5-6-7-7a heads, big valves, and machine off the AIR bungs from the exhaust ports
- Mild cam - something like this:
https://www.jegs.com/i/COMP-Cams/249/SK42-208-4/10002/-1-The aluminum 350 Performer intake is perfect. You don't have much play in the intake because you need to keep close to stock carb height.
- Headers and duals with an X-pipe
You will likely need to fatten your carb up some. HEI shoud be OK.
Don't know what you have for a rear gear - you may find you need a taller gear and a slightly looser TC