[Jay S]

I will wait and see what the Crower custom cam looks like, not enough info to really say what it will run like.

When you are looking at Crower SFT cams keep in mind most are more symmetrical lobe designs. Ultradyne does not have a lash ramp on the opening side of the lobe, Crower has a lash ramp on both the opening and closing. For a Crower and Ultradyne SFT to peak at the same RPM the Ultradyne needs about 5*@.050” less duration. But the Crower will pack more power into a narrower RPM band if the Ultradyne and Crower have the same LSA’s, which can be good or bad. They are two cam companies are not super easy to compare when look at the specs. Those changes Lee was talking about on his old 247* Ultradyne with the wider LSA and less duration on the intake would be closer to a RA 4 cam with more power and TQ, I would expect that would have screamed in his old Firebird.


The 60311 is bigger than a RA4 cam, they are really not equivalent. The 60311 is hit and miss for vaccuum brakes versus an RA4 cam on an A body unless it has more compression. A RA 4 cam needs a 1.7 rocker arm to run with a 60311 with 1.5s for equivalent peak power. But even with a 1.5 the 60311 will still set the tq peak about 500 RPM higher. It could probably be advanced and lashed loose and get closer, but it will be a compromise somewhere.

When 1.7s are used on the 60311 it will out power the RA4 cams with bigger rockers by 10 or 15 HP, probably more if you had a lot of head flow. The max power would be the nearly same RPM at about 5600. After 5500 the 60311 will carry the power almost to 6000, the RA4 falls off like a rock after 5500. With a 1.5 rocker and a fairly stock round port aluminum head the 60311 will make about 500-510 HP @ 5500 and 530 ft*lbs @ 4300. A cam like typical RA4 cam will make the same HP numbers 500-510 HP but it takes bigger rocker arm ratio like a 1.7 and tq is quite a bit lower, 3600 to 3800. The 60311 likes deeper gears that keep the RPM’a up, can also move the cam timing around and tighten the intake lash at run a fair amount more compression than the RA 4 cams.

Edit: Sorry, I had the wrong dyno file down loaded. I will see if I can find the correct one.