Originally Posted by spinn
Cobalt , is correct. The series 2 v6 gmp beehive springs, retainers, and umbrella seals will get you the clearance. The progressive spring rate and reduced recirpcating wt is a bonus. There will be benefits.
My installed cams are under .450 lift , but have confidence in the info . Look at the set up on my 305.
On a 360 the magnum heads can take the same valvetrain. The gmp beehives ,retainers, and viton seals work. Add a mp5249549 204/208 cam 1.6 rockers at .458/467 lift adds 46hp and 51 lbs to the magnum 300hp crate. That is not peanuts. A stones throw from the radical 380 crate, and smooth.
What are the specs on those springs- seat and open pressure? And what brand of headers are those? Look like they fit well.