I am planning on some ported heads for my 350. I am thinking of adding TA big valves too but want to know if its worth the $ (canadian+shipping etc). How much power will I actually gain from using the bigger valves?
If you are going to be racing the engine, especially with Nitrous, and/or high valve spring pressures, then go for it. If you're going with fairly serious porting, then it's worth the additional bucks there as well. The size difference is minimal between T/A valves and stock, but stainless is a better material than our stock steel valves, and can take heavier use. My $.02
