Hey Brad, I have 78 TA W72 - I originally rebuilt the stock 400 and used Summit 2801 cam and headers. I used stock intake and stock 78 W72 quadrajet and ran fine. I converted the 400 into a stroker - but kept stock intake and quadrajet. The 78 W72 qjet is 800cfm and a good carb. I would try and rebuild the carb yourself. It is not too hard. The carb can often benefit from a good cleaning and some new parts like float. For parts , I used
https://cliffshighperformance.com/ , a bit pricey but the parts are top quality. Cliff also publishes great book on rebuilding - setting up a quadrajet.
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For tires, 255/60/15 fits nicely and looks good - I have 255/60/15 Yokohamas, though when I replace will likely try Cobras
https://www.tirerack.com/tires/tires...omCompare1=yes
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For exhaust
https://www.summitracing.com/parts/s...model/firebird
https://pypesexhaust.com/c-702350-gm...-trans-am.html