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Discussion Starter · #1 ·
I have a 390 4bbl from a 66 thunderbird in my truck and it will not run w/ a carb spacer. If you bolt the carb directly to the maifold if idles smooth as silk and has good power and throttle responce. If I put on a 1" 4 hole factory Ford spacer it stumbles something fierce at all rpms and will not idle. There are no visible cracks or holes on the spacer and I went so far as to fill all the voids and indentions w/ JB Weld and then block sanded it flat so I have 4 perfect holes w/ no vac ports or indentions. I would really like to run this spacer for the added power and heat insulation but it will not work. Anyone have some insight as to what in the world is the problem.

-You can never have too much power, just not enough traction.-

7,032 Posts
First thing that comes to mind is a vacuum leak. Did you put a vacuum gauge on it? Spray around the mating surfaces with WD-40 and watch the idle and exhaust. If the idle goes up or white smoke comes out the tailpipe, you have a leak. Make sure the WD-40 can't get in the air inlet to the carb, tho.

Jim Vogel
Tallmadge, Ohio
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