I have been reading post off and on here for a while, I thought I would ask some opions. I am currently rebuilding my 265 from my 1954 (Canadian) Desoto, here is a list of what I have.

1-265 long block full flow oil system
2-Edgy head and camshaft
3-edmunds twin intake
4-Langdon headers

I would like to rebuild this so it will last, it will not be a racer, but will get driven long distances, and get the ocassional hard drive. the car has a 2 speed powerflite Auto, I have installed 3.23 gears.

1-should I line bore?
2-should I balance the rotating assembly
3-what about the modified oil system I have read about,do I widen the main bearing oil grooves so they match the block hole size.

Any tips would be appricaited, thanks

I think you should get rid of the Powerflite and fit a manual with overdrive... that will give you greater longevity and driving comfort whether you take the other steps or not.

Line (or align) boring will depend on how straight the block measures up in the crank tunnel. If it's straight, no need to bore.

Balance would probably be a good safeguard and could give you a minor improvement in smoothness.

If people who know these engines (George Asche etc) recommend the bearing mod, I'd go with it.

I'd also look at enhancing the front brakes, either going to larger drums or to discs, but try to stay away from power boosters unless it already has one.