AJ's Opinion; what size SBM do I need

Ok, back to engine talk. If you go with the conventional wisdom that a 4" bore is the nominal size for a "small block" performance platform (I do) then the 318 falls short.

For comparison, whether 2bbl or 4bbl, both the 302 and 327 were designed around a 4" bore. Besides the increase in up swept volume, one would realize the other key benefit of the larger bore is reduced valve shrouding. With either of those ancient Brand-X choices you wouldn't have to deal with that negative aspect of the architecture before you even start like you would with a 318. Heck even the 289 had a 4" bore too. '65-66 K code would wipe up the floor with any 318.

Not sure why some of you guys get stuck in this mindset that 318s are worth pursuing, especially over a 360. They were never designed as or meant to be performance engines, just basic motivation across multiple platforms. In reality they were under powered, gas guzzling boat anchors for their entire 30 some-odd year run. When you look at the design of the LA 318 from a purely factual/logical/scientific viewpoint, you'd be hard pressed to justify building one up because the basic architecture isn't there to support it. How many 318 combos running in NHRA Stock or Super Stock? Not too many. If it was favorable you'd better believe there would be lots of them out there. Both were and are still readily available cheap so if you have to chose between one or the other, the 360 is the logical choice. Last 360 short block I bought was maybe $100. If you want to build one for your own amusement and have the means to do it, knock yourself out and prove me wrong.

The 360 wasn't a world beater either in stock form because it was never produced with any real compression. But, as a build platform, it's got the magical 4" bore and can swallow a 4.25" stroke even though it's basically the same externally as the 318.

Same story with the 383 vs. 400. 383 was a pedestrian big block with a relatively small bore that found it's way into millions of cars. It was replaced by the 400 which over the course of it's run was mostly a lo-po torquer/dog in factory stock form. it is generally thought of as the go-to for big power low-deck strokers. Why? because of the 400's 4.342" bore which is the largest bore of any muscle-era Chrysler production engine. Don't see many guys building 383s because for the same money you can build a 400 based combo that nets more cubes and the potential to make way more power. Same block externally.

You have missed the point and thinking this backwards.
Let me explain…..

Many here don’t have the money to go out and repurchase an engine, have space for another engine, the means to easily get ride of the “Boat Anchor” spare engine or just simply want to build the 318 they have in the car. Be it a full rebuild for stock, mildly hopped up or hard runner.

I don’t know if you yourself have ever been limited to such a degree where doing much of anything else besides dealing with what you have within the means you have limits you to the engine at hand. The one in the car.

If your seeking help and your limited in one or more of the above or just simply wanted to do the engine you have, in this case the 318, why would you not help that person with what THEY want to do?

I believe that no one here is stating what you seem to believe above.