black smoke
#1
Junior Member
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Thread Starter
Join Date: Jan 2004
Location: South Dakota
Posts: 18
black smoke
having problem with tow rig. 350 chevy engine, single plane intake (i know its not perfered for towing) holley 600cfm with vac. secondaries manual choke, in a 74 gmc 4speed manual. Had same problem with 750 vac. secondary, this 600 carb came off a good running 454 about a year ago Smokes black while driving, could this be a power valve problem
? Vac. advance seems to be working, choke is off. any advise appreciated.
Ryan
? Vac. advance seems to be working, choke is off. any advise appreciated.
Ryan
#2
Senior Member
MASTER BUILDER
Join Date: Nov 2007
Location: Wisconsin cheesehead!!
Posts: 213
could be the power valve if it smokes after a certain vacume is achieved. otherwise I would think going from a 454 to a 350 you will probably have to downsize the jets a little. Im thinking the BB needed a little more fuel.
what model carb is it?
I have a dual plane SBC wieland stealth mani sitting in my garage if you want one. I dont have any need for it right now.
what model carb is it?
I have a dual plane SBC wieland stealth mani sitting in my garage if you want one. I dont have any need for it right now.
#4
Senior Member
MASTER BUILDER
Join Date: Oct 2003
Posts: 144
350 cubic inch motor would create a higher vacume rate than a 454 due tot he restricted cubic size, thus the fuel is just being pulled out of the bolsters. try downjetting from 66 to possibly 60 then try it out.