Joe, I wasn't happy with the Howard F298 cam in my last 302, it hurt bottom end torque and the powerband came in about 2700 RPM. With an overdrive trans I was having to backshift a lot to get in the torque band. I like a Harley-Davidson type power curve, so I talked with Tom Langdon at length about cam profiles. We came up with a dual-pattern grind with about the same exhaust duration, but shorter intake duration and less overlap. This after taking into consideration vehicle weight, drivetrain including flywheel and clutch weight, transmission ratios, gearing and carburetion.
There are so many variables, including your own personal preferences. Some of us like a lopey idle and lots of top-end power. So it's hard to make a recommendation without considering all these factors.
Tom then ordered a cam from Delta with his recommended profile. It came with a "Cam Doctor" printout so I was sure it was ground correctly (believe me this is not to be taken for granted!)I degreed it in carefully to be sure that it was working as designed. Good thing I did, it was 2 degrees retarded, easily corrected with an offset crank key.
I can't really say how it all turned out because the truck isn't on the road yet, but I feel like this is really the best way to avoid an expensive mistake. Talk to some cam grinders and if they don't ask you similar questions, they aren't doing their job.
BTW, reboring for those 1/8" oversize pistons is not something I would undertake without considering several things - it could take several passes on the boring machine, which can be costly. Also,it's taking a lot out of the block and could cause overheating. This kind of overbore was done routinely on race motors in the days when GMC's were cheap and expendable, but the extra 20 cubes or so won't make any noticeable difference on the street. I know GMC pistons are expensive, but it may be cheaper in the long run to stay with a mild overbore and new pistons. I also feel that balancing a street GMC, beyond matching the piston weights, is not cost-justified but I'm probably out-numbered in this opinion. Just my unsolicited 2.5 cents worth...
