We raced a non wing sprint car, steel block,self starting 360 ci on alcohol with no problem 4412 2 barrel was required,
This ^^^^^ @Mikey67 A 650cfm Carb is good enough for 390hp [using the formula of 1hp = 1.67 cfm] If a 327 [331? with overbore] got 1 ft/lb torque per cubic inch it should be making 390 at approx 6200 rpm
If you like really nice chrome you probably don't want original GM versions, even if you could find a set, they are pretty thin on the plating, at this stage they would require replating anyway. I had been looking for a pair for quite a while (in the early 90's) with no luck so found a nice pair of plain 283 covers and had them plated, if you look at my photo close you will notice that the polisher at the chrome shop got overzealous and rounded off the letters.