Hi again. The lift and duration theory is definitely NOT a myth. As a very rough rule of thumb, with pretty much any cam, lift gives your torque and duration gives you horsepower. A while back, I ran a Sig Erson RV cam in a 194. The can specs were 256 degrees advertised duration and .487" lift, and with headres and a 2-barrel carb, it put out LOTS of torque for a motor that size. I don't think Erson offers that cam now, but the Comp Cams 260H is pretty similar, and I think your 264 would work fine. The only difference between solid and hydraulic lifters (aside from the mechanical construction) is that you don't need to do valve adjustments on a hydraulic lifter once it's been set, but you DO need to adjust solids periodically. What determines torque and horsepower is the cam lift and duration. It has nothing to do with the type of valve lifter used. If you have 1.5 ratio rockers, those figures would be correct, but I don't know what the rocker ratio on a 261 is, but what you're mainly concerned with is total lift at the valve, and the valve/piston clearance. Your cam grinder should either know or be able to find out what the duration at .050" is. As Larry said, it's always a good idea (although somewhat time consuming) to check the valve to piston clearance with any new cam you put in a motor. You can do this by putting a 1/4" layer of modeling clay on the piston top, installing and torquing the head, then rotate the engine by hand one full revolution so that both intake and exhaust valves open and close, then pull the head and measure the impression in the clay on the piston top. And you could run either a 264 or 268 degree cam; the 268 will still give you good street performance, but will have a bit more lope to the idle than the 264, and the power band will start a bit higher in the rpm range than the 264, but will give you a few more horses at the top end. Everything in tuning an engine is a compromise; when you gain some here, you lose some there. As the engineers put it, "There's no free lunch". So basically you try to make your best guess as to what will produce what you want the engine to do and take a shot at setting it up with components to achieve that. So far it sounds to me like you're on the right track. Good luck with the project. Oh, yeah one last thing, a compression ratio of 9.1 to 9.5 should work fine, just remember to have your machinist install hardened valve seats for unleaded gas and you should be fine to run pump gas.
