340 engine repair/build questions
I had the exact same situation.
Bores cleaned up @ .040 but one needed 1 sleeve. I used the exact same new Silvolites that you currently have. They are a cast piston that installed at .017 above my deck. I redid my stock rods and used the original forged crank and did not balance. Engine runs strong and smooth. Like you, this is a punchy cruiser engine.
If it were me, I'd try cleaning the rust off with solvent and a scotch brite or some other mild abrasive. Any pits in the "stroke zone" and it would be off to the machine shop for me.
Good luck.
I've told on here before about a Slant Six Marine engine in '56 Higgins 17 Utility boat. Bought whole boat for $800 with stuck engine. Before doing anything filled cylinders with Knocker Loose & soaked it
while I looked it over & noticed a crack on the head. Went to Wrecks and got another head, non marine.
Took head off & 1 cylinder was very rusty so I sanded off the rust, wiped out the crap & re Knockered it to soak over night. Piston over half way down.Next chance I cut the corners off of a 4x4 so it would fit snugly in the bore and started hitting the 4x4 with a sledge hammer until piston moved. Then re-oiled & moved it down with a socket and then wiped & sanded. Then up & down, oiling & wiping until clean, then with 30w ND & wiped some more.
Then reassembled & it never smoked in the years I water skied with it.
And The Higgins was the finest Ski Boat I ever owned, hull very light, built like an Aircraft Spar, & Slant Six pulled hard out of the hole.
Long story but shows how excellent Chryslers Metallurgy was then, so previous post may've been joking, but is actually correct in saying you might be able to sand it off and get away with it.
Be very clean for reassembly.
Bet others have done the same.