[blykins]

How many rpms are you planning to turn?

On my 347 ci 1/8th mile engines, I run about 250 lbs seat with close to 600 lbs open pressure. These engines peak at about 6500 and are shifted at around 7000. An .080" 5/16" pushrod would work, but I would prefer to use a 3/8" pushrod if you have the room. Spring pressure is king here, especially when turning the rpms that I think you're going to try to turn. I run some hydraulic rollers at 165 lbs seat pressure. You need more.