Hey Jeff,
The picture of the cam lobe doesn't appear to have a problem. The reason it looks porous on the one side is because flat lifter cams have tapered lobes to spin the lifter to utilize more surface area for better longevity. But, since you told me your cam is from the mid-80's, then it is time to update to a better profile to suit your needs today.
I have to disagree with the split pattern. I do not see a need for excess exhaust duration. The int/ex port flow balance on the 2v head is pretty good from the data I have seen. If you were to keep the 351M heads with the restricted exhaust port, I would add another 5-8 degrees to the exhaust duration. But, since you have said you were going to install a set of 2v Cleveland heads and use headers you will have a pretty efficiant exhaust in comparison to the intake. If you were keeping exhaust manifolds, I would recomend a few more degrees on the exhaust.
I would say to run a cam with about 216-220 @.050 with no more duration then 274ish for the advertised duration. Fast lobe ramps allow you to have have more duration where it counts without reducing too much of valve-closed time--which in turn will retain your good idle charactoristics and at the same time make more power.
The Comp Cam that Jim recomended has quick ramps to it, the only thing about that cam that I disagree with is the 110 lobe seperation angle. The draw back to having a narrow lobe sep is it'll make a rougher idle, in which you may have to raise the idle rpm somewhat to compensate for any loss in vacuum or if you desire smoothness. The tighter lobe seperation will make a higher peak hp, but the power band is slightly more narrow---a little beyond idle--hence the rough idle and lower vacuum at idle. The wider lobe sep will have a wide power band, but the peak hp won't be high. The wider lobe sep angle will have better idle charactoristics and make more vacuum at the same given 268 duration. It more or less depends on your desires. The 110 LS on the Comp Cam may be what you are looking for, it will feel slightly more peppy then say a 112. The durations on that cam are pretty short, which will keep the overlap down to within reason of drivability with a 110 LS. If you happen to get too wound up after reading this then you can alway go for the compromise of the inbetween on the lobe seperation angle.
All in all, don't stress over a few degrees of duration. 10-12 more degrees might cause an unwanted difference. Just be honest to yourself with the intended use of the vehicle, then weigh in you desires of performance. If I could throw out a number, this is what I would pick for your car if it were up to me:
A single pattern with about 268-272 advertised with 218-221 @.050 with no tighter then a 111 lobe sep. I feel this would suit your needs with cruising, ability to make suitable vacuum at a realistic idle of no more then 650-700 rpm's and meet your desires in making some pep.
