On a Chevy 350 V8 a 600 cfm carb will support 375 HP with 400 ft lbs of torque.Inlines have different cfm requirements,but not that much different.390 Holley is really still too big but works ok.A 350 Holley 2300 two barrel works very well from my actual experience on extensive carb testing with both a modified 261 Chevy and 302 GMC with water heated intakes.Again,the 250 engine is different than the two I mentioned....I never got a 500 cfm Edelbrock to function properly on the 261 or 302.The carb was good at part throttle but always a bog when the secondaries opened no matter what jetting or fussing with the secondary air flap.Some guys think a bog is good, the engine stumbles,then picks up and they think it's accelerating harder,but it's actually slower.
From a fuel distribution point of view,two carbs is better than one ,but the centrally located carb can be made to wrok out ok.
