Holley 390 4bbl on my slant 6?

I use a Bouchillon throttle and kick-down cable bracket, and a Holley Chrysler throttle arm adapter.

Even with larger exhaust on stock engine a 390 may be on the big side, and your engine may not be able to fully utilize the secondary side of this carburetor. Best scenario would be to install oversized valves, and higher lift than stock cam to get that engine breathing a bit better.

http://www.bpeusa.com/BPEaccBracket.asp
http://www.holley.com/20-7.asp


Here is a carb size selector you can play with:

http://www.holley.com/applications/CarburetorSelector/CarbSelection.asp