Sometimes, a little extra exhaust can help cylinder fill. But this and many other factors of cylinder filling and optimum efficiency in a given parameter (engine/cam rpm range) can be a huge trial and error experimentation. There are so many things to look at and consider when that cam starts turning.

On single pattern vs. the use of a split duration cam, I have found best results with a split pattern and stock heads. Why? Because the exhaust could use that help? I think so. On ported heads, I haven’t seen any real advantage with a split pattern and the single pattern ran quite nice.
No 1/4 slips. Just basic street builds.
Still playing around with cams in the various engines.

While this thought/idea may not play out accurate, perhaps a computer sym like Desk Top Dyno could be helpful in at least show what could happen with a different cam. If anything, it could be a helpful tool in showing what is possible/probable.

Have there not been published reports on flow balances between the ports and suggested cam specs for such balance

Depending upon what the end user's goals are, that's not necessarily a "must have", IMO.

Even some of those that have been advertised as designed for a .904 lifter are lobes that could probably work OK w/ an .875 "Ford" lifter, since the cam designer(s) didn't set them "on kill" as far as using the full lifter foot diameter.

Also, "Faster" isn't always "Better" when it comes to cams, but it seems to me that most people don't want to believe it. If you want to turn some RPM with a hydraulic cam, the fast rate-of-lift lobes are also more likely to experience valve train "crash" at a lower RPM than a less aggressive lobe.

They may help to show trends, but the more I used even a fairly high-end simulation program, the less I came to expect results that reflected the real world (at least compared to my experiences).


Well... there have been lots of magazine articles that attempt to simplify things to that level, but the reality is it's not that cut-n-dry. There are too many other variables that influence things (e.g. CR, RPM range), which is why IMO it's better to work with someone who is familiar with the type of engine & combination you have.

I have never owned a dual pattern cam. I have been 9.60s 1/4 mile with a junkyard headed Stroker SB, LA 587 smog castings, in 3000+ car with 727/Dana 60. Racer Brown STX-22 SFT Cam was actually made in 1971. In another tank car, 4200# 79 Chrysler "300", with another stroker SB with same junkyard 587 heads and a Racer Brown STX-21 SFT cam, has been 11.20s at 118 mph. In another car with a Indy SR headed 512 c.i. BB with another RB STX-22 SFT cam, have been 8.50s at 157mph. Car is a 89 Chrysler LeBaron and weighs just under 2600#. Have never lost a lobe on any engine in any of my cars, except one that was a used cam, someone gave me, with new lifters.

As someone in earlier post said already, Call Jim at Racer Brown. He will set you up with a perfect camshaft.