Large valved 273

replicaracer43 said

Dont forget, ANY cylinder head you bolt on to that small bore, will flow LESS air on that engine compared to a larger bore. Therefore the 273 is handicapped from the get-go, plus harder to get compression in a small bore, that's the reason the factory had to use a dome piston. Probably the WORST SBM to build, unless your just doing it for originality or nostalgia.

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The 4 main problems building a 273, getting high CR out of them, bore size obviously is gonna cut down on air flow, but these aren’t the biggest problem for most builds but rpm, a 273 is gonna have to turn 1500-2000 rpm higher than a similar hp 360. Which to me brings the main problem gearing most don’t want to go with more than 3:55 which is under gear for most combos but a decent compromise for 340/360 but if you want to build a 273 that has any chance of keeping up with 340/360 your gonna need a lot of gear at least 4.10 or deeper and lots stall if it is a serious build.

To me when it comes to 273/318 if your willing to turn it and gear it then build it if not go bigger.