Hey guys, I was wandering if any of your hot rods put out bad exhaust fumes like mine. I have a 454 with 12.0/1 comp and a extreme energy 284 cam with 240-246 @ .050 duration and .574-578 lift. I just swapped carbs from a holley 850dp to a holley 750 vacuum secondary. I'm trying to get this car were my wife and I can drive it without smelling like exhaust fumes. I can tune on this car and stand beside it and get the smell all over me. I think the carb is working right because it runs good. Has anyone reduced their exhaust smell going with a edelbrock carb. All the motors I've had in this car stunk, but they have all been cammed up hot rod motors and all had holleys. Is it the big cams or the carburation. I'll start reserching electronic fuel injection and put that on if I have to.

Thanks, Kevin

Yes, my Willys puts out some world class noxious fumes! When I am working on it some times I break down with tears of joy and sometimes it's tears of pain!

Your rather long cam results in those raw hydrocarbons as the overlap prevent's a clean and total burn. changing carbs won't help you much if at all. What you need to do is run the idle mixture lean to reduce the hydrocarbons. Yiou can only go so far with this adjustment and still maintain decent idle vacuum. You need to increase the size of the holes in the idle emulsion tubes and rework the idle air correctors to reduce the hydrocarbons.

Or run the alky fuel fragrance in a bottle. It still works well with gas carbs.

johnsongrass1, these are the mods I did to the carb. I drilled a 1/8" hole in the primaries to get the throttle closed down. The idle fuel restrictions are opened up .004". The car idles good and takes fuel better after doing this. No fuel is spilling over. I've got a 5.5 power valve with 9" of vacuum. I,ve got a 50cc pump, 37 squirter and brown cam. When you said holes in the idle emulsion tubes is that the idle feed restrictions? Also I've never heard the term idle air corrector? On the fragerance a friend just suggested that yesterday but I dont how it could kill that much stink. Does it work pretty good.

(I've never heard the term idle air corrector?)


I meant the air bleeds, I just called them something different. I call then correctors because that's what I was taught.

(When you said holes in the idle emulsion tubes is that the idle feed restrictions?)

Yeah, To increase the amount of air emulsified(mixed) in the idle mix you must increase the number of holes that are present in the main well. Careful when you do this though. For the placement and size are critical to get the desired effect.

As far as fuel fragrance, yes it works about as well as you could expect.. It will cost around $6 for enough to treat 20 gallons of alcohol. You may have to adjust for gasoline.

johnsongrass1, I know what holes you mean now I just never heard of anybody modifying them. I dont think it will help me because I had to go up on the idle fuel to get rid of a bog. I had the initial timing all the way up to 21 degrees just to rule that out. It still had the bog without the extra idle fuel. I even tried a drilled squirter. I think the carb is working like a normal holley. I know a lot of the problem is the big cam overlap we talked about.
I just wonder if anyone has had any luck getting some of the smell out using a edelbrock carb.

man you should smell my old chevy 307 it smells bad all the time.i live on a mountain when i start climbing it my engine puts off a ruff smell.i gotta a holley 650 and a holley street dominator intake on it and running headers and glass packs.