The 340 is the biggest POS V8 Chrysler ever made.

Ok so, "4 barrel 318". lets think about the differences, Larger ports in the heads, larger valves, larger bore, heavier rods, higher compression, cam, 4 barrel only intake, 727 only automatic bolted behind 340, I'm pretty sure the 340 had different rockers because of different "heavier" valve springs, camshaft is different, 340 rated at 275 HP, 318, I believe it was 235 at best, going by memory here. That's all I have off the top of my head. Similarities?, its the same basic block and head casting configuration. Accessories bolt up to it(Starter , alternator, water pump etc.) it geometrically fits where a 318 would, the crank stroke is the same, as is the main journal diameter, I think the rod journal diameter may be the same also, someone correct me if I am wrong. that's about all I have, if it was easy to convert a 318 to 340, people would, don't hear of it much,because a 340 is more than just the short block. I don't think you can bore the 318 much above.040 over, those that do aren't going by the book. Ok, talking big blocks in this thread is comparing apples to oranges, oh, and whats the expert opinion on the "windage tray"? doesn't that count as a "baffle". My opinion on oil starvation is, with a high volume pump, you need a deeper oil pan. :)