edelbrock makes an intake for the 4.3 chevy a SMALL 4bbl is plenty 450 cfm or so maybe 600 with vac secondaries a 305 chevy truck rochester works fine with a stock to mild cam. cad and buick cars from the late 70's with the larger 4.1 buick v6 also came with a similar small qjet if you stay with the fuelie set up talk to a gm parts man they have a nice package cam and chip set for about 300 bucks.