Just to expand on that a lil;
In my experience; there is a night and day difference between a Hughes HE2330AL and a Hughes HE3037AL.
For the smaller cam, the numbers are;
270/276/110+4/53 overlap/119 compression/108 extraction.
With this cam I was able to gear the engine down to 65mph =1600,( with double overdrive; A833od plus GVod)and the car returned phenomenal fuel mileage. Some would say impossible numbers.
The larger one is;
276/286/110+4/61 overlap/116 compression/103 extraction.
This cam would not pull the numbers. I figured the problem was the headers pulling raw fuel past the open valves during overlap, at the 1600 rpm. So I bumped the stick back one gear and 65=2240, and voila I'm on the right track. Cruise vacuum is up, and so is the fuel mileage.
To cover the loss of 119less 116 degrees of compression, I milled the decks to equalize the cylinder pressure, no problem there.
But the 108 less 103=5 degrees less extraction cannot be overcome so easily. And because of this, and I guess the 61 versus 54 degrees overlap, fuel mileage has dropped to 50%. Well, I changed to 295 tires from 275s at about the same time, so that mightof also contributed to the problem.. All in all I was very sad when that smaller cam dropped lobes.
But the point is this; IMO, there exists, in my combo at least, a switch point between these two cams, and I'm gonna go out on a limb and say it's probably in the split pattern, and my engine liked it. Heckya it makes waaay more power, with the larger cam. But I really miss the fuel-mileage.
I already have ideas for my next cam,lol.It will be a solid FT.