You'll hear the name "Clifford" come up, but be very careful before you decide to spend any money with Clifford. They have a long and ugly reputation for being a bunch of clowns; see for example
here,
here,
here,
here, and
here. Much of what they sell is inaccurately described, and a lot of it is not even slightly cost-effective. The good news is that you don't need to go to Clifford to get hot rod parts for slant-6s; there are lots of other, better options. See for example
Dutra Duals and header options discussed in
this thread and
this one,
Erson custom cams,
HEI ignition upgrade,
Mike Jeffreys windage trays,
Hurricane intakes,
other exotic intakes. Hi-perf engine buildup
here, high-perf parts and build info
here. (some of these links may be broken while we're waiting for slantsix.org to come back up)
As for Clifford's recipe they sent you, No. Unless the goal is to just funnel money to Clifford, you don't just blindly take some prescribed amount off the head and do other such mods. That way lies sadness, despair, and wasted money. Instead, you
measure and figure out where you are with your particular parts—combustion chamber volume varies a lot, for example—and then you do the calculations to figure out exactly where you want to be with the specific (pref non-Clifford/non-Comp) cam you'll run, the gasoline you can get, the altitude you're at, the kind of driving you'll be doing, etc, you talk it over with people who actually know what the eff they're talking about (not just trying to make the cash register ring) and
then you have your answer as to how much to mill off the head and/or block.
