Good example of a 455 street engine with a hyd flat tappet, just change it to a similar hyd roller cam.
Stated- "This is a fairly mild working daily driver combination, making approx. 425 hp, in a car that can run 12.40's with stock type suspension, a/c & weighing 3800 lbs."
Too much duration ?? I don't think so !
Camshaft: Comp Cams #XE 268H Hydraulic cam and lifters(this cam works from 1500 to 5500). 224/230 duration @ .050, Lift:.520 intake/.524 exhaust, with 1.6 rockers: advance cam 2 degrees.
http://www.angelfire.com/fl4/pontiac...nebuildup.html
455 Engine Build - New-Age Super Duty
Cam: Comp Cams hydraulic-roller, PN K-51-423-9
Duration at 0.050: 224/230-deg
Lift: 0.552/0.561
Lobe Separation Angle: 110-deg
http://www.highperformancepontiac.co...ild/specs.html