Recommendations will depend on several things. Need more info.
Like:
(1) Is your engine original numbers matching, and if so, do you wanna keep it that way, including the heads ?
(2) Or, is it OK if it just looks sort of original ?
(3) Aprox how many miles per year will it be driven ?
(4) What is your total budget for the entire engine build ?
A few options:
(1) If your engine is original numbers matching, I'd store it, for possible future resale of your car.
(2) But, if it is not original, I'd use the block for the rebuild. If you don't care about numbers matching, I'd go with 6x-4 heads, or 5c-4 heads, or even late '73 or '74 #46 heads. My choice would be the 6x-4 heads. If your budget will allow, I'd go with 2.11/1.66 one piece stainless valves. If you go with the larger 1.77 exhaust valves, it is said that you need hardened valve seat inserts.
(3) The cheapest decent pistons are the Speed Pro L2262F forged pistons, in the oversize you need. The Ebay price is about $320. Less than $400 with rings.
(4) Better pistons are the Auto Tec brand. They are lighter, use the modern, thinner ring sets, will produce slightly more compression. But, I think one of the biggest advantages is the fact that they will relocate the pin holes, in order to position the top of the pistons closer to the block deck. This will reduce machine shop costs, by requiring less material to be machined off the decks, in order to achieve the desired near zero deck height. Total shipped price is a little over $500. Rings not included.
(5) Most nowadays don't recommend using the 40+ year old cast rods. The cheapest forged Pontiac rods are the RPM 5140 I-beams. But, for only about $100 more, the RPM H-beams are a much better value. They come in either floating or press-pin versions, for $400 shipped. Some say it costs over $200 to rebuild cast rods, with new ARP bolts. I think the RPM H-beams are the best rod value.
(6) The compression ratio for this combo will be somewhere in the middle 8's. So, a Voodoo 262 cam may be about the best cam choice, for what you have described.
(7) The cheapest decent lifters I know of are the $59 lifters sold by Paul Spotts, on Ebay.
(8) Crower sells some "Cam Saver" lifters, which supply extra oil to the cam lobes. Some Pontiac guys recommend ONLY Hylift Johnson "R" lifters.
(9) 3 valve spring possibilities are: either of the springs sold on Ebay by Paul Spotts, or Comp Cams 988-16 springs, or Crower 68404-16. The stock replacement Spotts springs are the cheapest. The Crower springs are the highest. If the engine won't go past 5000rpm, the cheaper Spotts springs or the CC 988-16 springs may be OK. But, if you plan to rev over 5000 rpm often, the stronger Spotts or the Crower springs will be better.
(10) If you wanna go with some of the early, big valve heads, like #16, #62, #48, #12, or #13, most recommend hardened seats, at least on the exhausts. Might also need dish pistons, to reduce compression, for pump gas use, unless you wanna mix in some race gas or a good octane booster, like Torco Accelerator.
Well hey, there are a LOT of different recipes for a Pontiac street engine, These are just a few ideas.
