273 and 318 the same block?
buy a 318 stroker rotating assembly to achieve a 390 ci engine? If so, then I'd need a 318 compatible heads, intake, and carb, correct?
I wouldn't build a 390 except in countries were 340/360 are in short supply. Not that there a particularly a bad engine, just power comes from in the most part is by air flow, breather to exhaust tip and that includes bore size. Bore size is probably one of the ultimate factors that limit power potential of an engine. Cause of valve shrouding limits valve size and valve size limits head flow potential.
So since all parts pretty much can be swapped between engines with a little work except pistons that would make bore size the only real difference between engines.
So 340/360/318/273 would be the order of bore size from largest to smallest 4.04"/4"/3.91"/3.625", 340 would be the best choice if they were as plentiful and cheap as a 360, to me on a ground up build still worth trying to get one for the few extra hundreds they go for, more air flow and Cid potential especially if your trying to go with heads with bigger than 2.02 valves. 360 there's really no reason to build anything smaller and cause of cost and being the largest stock engine it can be argued that there's no reason to start with any other small block. It does come with the best compromise of bore stroke and rod ratios. 318 if you got a good running one it's worth to do the basic hot rodding hop ups but for a full build a 360 would be better especially if shooting for over 400hp, but under that the smaller bore of the 318 ain't that big of a deal but your gonna need more gear and stall to keep up with the 340/360. 273, with some raw head castings and a Nascar budget probably could make some serious power from the small bore, but theres probably not very many 273 running around with more than 300 hp, and gonna need a LOT more STALL and GEAR to keep up with a similar hp 340/360.
Stroking makes sense on a street engine since it will move the power band down in rpm, needing less stall and gear especially since most seem only want to run 3.55 or less. And in a race engine where power level would need to turn a stock stroke engine north of 7500 rpm. Even though you gonna give up some hp and life to increased friction.
What about a stock to 0.030" bore 273 with a 3.580" crank? Granted it would only have about 290 cubic inches, decent engine? Doable on a budget?
Depending on desired hp this wouldn't be a bad combo
still would have great rod ratios and still on the over square side ( bore stroke ratio) and with the extra cubic inch it would bring the power band down a little. But without a good head porter it would be hard to get more than 350hp, it probably make a good 1 hp per Cid gas mileage engine but you would be further ahead going larger bore engine.