225 slant rebuild for more power
You don't want a high volume oil pump in a slant. Best to either use a stock volume pump, or a stock volume pump with a high pressure spring, but not the high volume.
There are a several items on that list that have a poor benefit to cost ratio,,,
The Mallory distributor, no vacuum advance,, expensive,,
Just get a stock slant electronic distributor, re curve it as necessary, run a HEI ignition.
The replacement rods and pistons,, again a lot of expense, useful in an all out race engine. But lot of folks have ran turbo power boosted slants using stock rods and pistons without rod or piston issues.
head and main studs,, again all out race engine stuff
are just a few of them.
I agree with keeping your first build basic,
Raise compression, basic bowl work, new timing chain and bearings,,,,