Greetings from France, this is my first post so please go easy.
I've a 1989 L98 350 Tpi from a Camaro which I'm currently installing in a 1954 Chevy 210 2 door sedan.
Its been converted to a speed density system with a corvette style ECU and bare bones harness, I bought the car as an unfinished project and this is the motor that came with it.
Therefore the condition was unknown so I decided to take a look inside and found no.1 main brg had spun in the block, no signs of overheating on the crank/block or rods so its now at the machine shop getting align honed and a crank regrind.
Apart from that the motor looks in really good shape, no noticible wear in the bores, clean inside etc.
I found +0.020 oversize/ 0.010 undersize mains so they are honing the block for those.

My first question is pistons, I want to fit new but am unsure of which ones, I've narrowed it down to either SEALED POWERH345DCP or SEALED POWERH423DCP
The 1st is 6.9cc the 2nd 12.3cc
My 083 casting heads are 64cc so if I deck the block to 0 and use a 0.039 head gasket I get 9.35:1 or 9.91:1
Over here we have 95 and 98 RON which is equivalent to your 91 and 93
Would 9.91:1 with 0.039 quench be ok or should I go with the 9.35:1?

Second question is cam, to swap or not? I'm not looking for a drag car, I want a nice cruiser with a bit of oomph when asked for.

Finally should I stick with the stock computer or go aftermarket? I know it can be tuned but by the time I've bought the necessary to do that I'd be half way to a Holley Terminator X which has sequential mpfi as opposed to batch fire, not sure on the gains of that though.

If you made it this far then thanks for reading.