Evan - before I was bitten by the "buy American" bug, I had a Datsun Fairlady 121 CID with two 500 CFM Mikuni 2-barrel carbs. This was a factory (Datsun) installation. It ran like a scalded dog! How long would they last? Don't know, as other circumstances forced me so sell the car with about 35k miles.
Later, we sponsered a winged 4 cylinder (Pinto 2000 engine) dirt racer. The owner found and acquired an intake with 4 Mikuni side-draft carbs; and AFTER SPENDING MORE TIME ON THE CARBS THAN I SPENT RESTORING MY GTO ENGINE they ran like a scalded dog....for about 1/2 the season. By the end of the season, the inferior zinc alloy metal was totally worn beyond repair!
As one grows older, one realizes that time is one's most important asset. I wouldn't personally do the Mikuni nightmare again. Period.
If you are 18 and have more time than you know what do with; and unlimited resources to spend on additional venturii, main jets, air jets, compensator jets, etc., etc., etc., go for it!
Jon.
