[YoungTiger428HO]

I purchased a set of SpeedMaster78 PCE281.2168 . Flat tappet Hyd. They have been fine. I have had no issues in the year since a put them on. I made no modifacations. They are on a 461 cid Pontiac Eagle rotating assembly. 10.2:1 with 1.65:1 roller rockers. That gives .528 lift with 13/32" ram air pushrods and 7/16" studs. Also had to change head bolts and go to round port headers. This motor just run great. I use a 1/2 a bottle octane booster every tankful. I don't know what the actual horsepower is but you hardly need the gas pedal!