Where can I buy water & fuel pumps?
Welcome to the board.
I am with Beater on this one. You will be surprised how much you can get from NAPA and Rock Auto for these old engines. I always look there first before paying specialty store prices. BTW NAPA has all pulley size variations for GMC (3/8, 5/8 and 7/18).
Also, to add to FTF's comments on camshafts - I am old school so I don't mind the language of our fathers when it comes to describing cams. But we need to keep in mind what these terms represented in their day: an off-the-shelf speed part to be used in an overall formula/recipe of upgrades.
A cam re-ground "3 quarters of the way to Full Race" was typically 30-35 degrees longer in duration over stock - with a grind that basically followed the stock cam geometry in terms of Lobe Separation Angle LSA and Lobe Centers LC. Additional lift was limited because the amount of material removed the from the base circle was purposely limited so that the stock push rods could be used (with just the valve adjusters taking up the lash).
These guys were trying to sell speed parts to kids on a budget running daily driven hot rods. The low end modification$ were typically done in stages with the car being down Friday night and all day Saturday - ready for church on Sunday or worse case work on Monday.
With a hobby car being built in today's world one need not build to a formula - unless that is what you are after. One can have a cam ground to one's individual specification with Valve Events, LSA and LCs where you want them (within certain limits imposed by the cam core).
On my personal 216 Chevy build I have chosen a dual-pattern grind with much less duration on the intake then on the exhaust. This creates overlap to promote scavenging - but to FTFs point - closes the Intake Valves early enough to achieve peak power at a lower point in the RPM range.
While I am a fan of the old school hot rod books - they focus to much on the intake side of these engines. And many of the 'porting' recommendations are actually mistaken - as simply 'hogging out' material causes the intake velocity to fall.
The proper focus is in fact volumetric efficiency and ensuring that the camshaft design promotes complete sweeping of exhaust gases from the cylinder.
I find this article useful in understanding camshaft basics:
Austin Community College site with diagrams from Lunati to help visualize:
Lunati Power I recommend you spend some time studying and planning what you want from the build before ordering a cam.
regards,
stock49