stock comp. 318, which purple shaft is best?

Get your exhaust and ignition done then work your way up to the intake. A MSD will work fine with a stock electronic distributor. The MSD 6A is fairly cheap, it just doesn't have a rev limiter like the 6AL. But I don't think you need to worry about a rev limiter for a while. Let us know when you get the exhaust done, I'm going to be parting out a 73 Duster that has a LD4B on it. Thats the LD340 with 318 size ports and I don't run any 318's. The car has a 360 with 318 heads :scratch: I don't know what that guy was thinking. Anyway I'm not planning on using it.