Hi all, Ive got an XE268H cam and lifter set that i want to run in my "73 400 powered "69 bird.Its a stock 4bbl engine with headers and TH350. The heads are 7j2's..my question is what comp valve springs would suit these heads. Machining the heads is not an option as they are on the "replace list" when some better heads become available,(hard to find around here).
Depends on your use of the car. Generally you want springs with around 100lbs seat pressure at installed height and around 220lbs open at full lift. Now if you intend to rev it higher than suggested by the factory you will need stronger springs. Of course the stronger you go the more pressure on the cam lobes and the shorter the cam life. Your decision.
If you're not going to rev over 4600 to 4800rpms you will be fine with any brand of standard valve springs. Pontiac used factory valve springs as rev limiters to reduce warranty issues. I have a set of Erson springs that made good power to 4800 on a dyno before they started to float. They only have about 1000 miles on them. I'd let them go cheap if you're interested. I wanted some that would hold up to 6000rpms so I changed them out.
