308s vs Magnums

I think if you have a set of both, I'd run Magnums. You'll need new pushrods and lifters, which are off the shelf parts. You should be buying new ones of both anyway. You'll neeed to have the holes for the intake drilled for the std LA intakes, or buy Magnum or combo intakes. Everything else is the same. If you're careful, you can even use LA style valve covers to hide them. The exh port is better in stock form , along with the better chamber, and higher velocity intake port/vavle. The biggest issue is having a set of Magnums that arent cracked. If you are planning to go faster on the same heads later, then I'd run 308s built with Heads' ideas.