quote will disolve the iron bore almost as agressively as it disolves aluminum
In 25++ years of being a certified Honda & Suzuki mechanic & using muriatic acid to remove aluminum from cylinder walls, as directed by the Honda, Suzuki, & Yamaha factory service directives, I have NEVER had a bit of a problem, nor heard of any BS about muriatic not being the solution for that particular problem. We have ALWAYS had a jug of muriatic in EVERY shop I EVER worked in, and that is quite a few, from Alaska to Texas, Michigan & Indiana.
On another note, I went back through some of my AMC power literature, outlining SuperStock & TransAm AMC engine builds, and most of the engines put together with forged pistons used between .007"~.009" wall clearance, including the little teeny overbored 290 (302).
Pistons- you should be able to get by w/o another bore job, get yourself some forged flattops & hone the cyls for .007"~.008" clearance, as recommended by the mfgr. The CR that you order should be determined by the CCs of your combustion chambers, I'd want to be ending up with at least 101 - 10.51, & be SURE to have the .045" PTHC.
Not suree what type of mods your heads have had, but "open-chambering" is a very worthy mod that should net your chamber size to the low 70s, as I recall. Which would be around 111 with 13.51 pistons, so you REALLY NEED to know what size your chambers are & what your deck clearance is before you can order pistons. Generally, you will need to order pistons rated for 12.51 (or so) with 50 or 51cc chambers to end up with 101 with the 70-something cc chambers, so you MUST do the math FIRST, then incease the valve cleearance cuts in the pistons or the volume of the combustion chamber to lower the CR to where you want it. If you get another set of pistons that have domes looking like the stockers or the siezed ones, you will most likely have a ping problem at ANY compression ratio, because there is no way to get .045" PTHC with those pistons, and you would probably be very lucky to get much over 81 with them anyway.
Do yourself a favor & get the rods bronze bushed & use full-floating & forced-oil oiling, wrist pins.
Rings - I will always pay the extra $100 for gapless rings, they leak 0% after break-in, compared to normal rings that will leak at least 2% when new & always be in a state of deterioration, leaking 810% in fairly short order. That is around a 10% loss of power, & also may let a little oil into the chamber where it can cause detonation & engine destruction.
