I have a SBC 350 out of a 1974 Camaro Z28 (I know I am in the Chevelle & El Camino threads but there wasn't a Camaro thread that I saw) that I am putting in a 1984 Jeep CJ7 and I have had it running for over a year now off and on no issues(no smoke) but I had been running it off of the mechanical fuel pump and fuel line into a 5gal fuel jug in the passenger seat floor board. I finally got around to replacing my fuel system with a new tank, fuel sending unit, and 5/16" SS line going from the tank to the engine. After doing this I could no longer get fuel pulled to the engine off of the mechanical fuel pump alone so I purchased the Edelbrock electric fuel pump that is 2-3.5psi and 30GPM. After this it ran fine for the first start up to get it in/out of the garage to work on it, but after that and since then it has smoked an insane amount mostly out of the drivers side bank and only some out of passenger side... It is white/grey smoke so I know that 9 times out of 10 means head gasket or intake gasket but it only happened after I installed the new electric fuel pump and I havent noticed a loss in coolant. I haven't pulled plugs or done any of that yet but I was wondering if it could be an issue with having the lower psi electric fuel pump pumping to the mechanical fuel pump and into the carb and running lean? Any thoughts?

Thanks in advance for your help!

 

Are you positive that water/coolant levels are very normal? Sounds like a head gasket leak or a cracked block or head. If you had fuel injection it could be that that, but I've not seen a carbureted engine put out white smoke due to the carb.alone. I'd run a dry and wet compression test on your car. Make sure no coolant s getting into your oil as well.

 

I finally had time to take a look. No water has drained from the radiator and the oil is still good and clear no water in there. I did pull the spark plugs on that side and they are pretty fouled out, I also noticed that my carburetor is leaking out of the driver side gasket down onto the intake manifold... I tightened that down and started it up and it seamed to smoke less that is was which was leading to my thought of the mixture being too lean. Going to replace that gasket and see what happens.

Based on this does anyone have any additional thoughts?

 

Well in addition to being an expert on air-conditioning, I have rebuilt close to 100 carburetors in my time, not including dirt-bike carburetors, Personally those spark plugs don't look all bad to me, and using AC Delco plugs is a plus in my book.

When I was in High School auto shop back in the 1969-1973 era, gasoline had lead in it as an octane booster. We had a sand-blasting gig that could get all the lead and carbon off the plugs, so much so that with unleaded gasoline, one can get 100k off most plugs, particularly the iridium plug,s assuming your vehicle doesn't burn oil.

They had to get rid of leaded gasoline by 1975 when catalytic converters were installed, as the lead would render them inoperative and its toxic. With all the early emission control systems, they also dropped the compression ratio's as well, so I'd never touch a 1975-1986 car at all..They were complete dogs compared to the earlier engines.of the 1960's to early 1970's.

Chevy fooled around with electronically-controlled carburetors until they came out with the TB injection in 1988, but F**D had them beat with full-on with a fuel injection rail system, and increased compression ratio's,.as well. By 1988 things were looking pretty good, but by then in 1996 all American cars and pickups were using OBD II, as prescribed by law and Chevy came out with a full fuel injection system like they should have beforehand. Nothing wrong with the TBI system, but it was not all that strong on horsepower, compared to fuel injection, sans the carburetor-looking TBI system. Nowadays, I'm glad we have powerful high compression engines.

Edit: Sorry for all that nostalgia. Getting old now. LOL!. I'd run a dry and wet compression test on your Chevy. Should be no more then 15 % difference between cylinders. If not something is worn or broken.on your engine. As to the carburetor, I'd do a full rebuild or buy a new one. I'm guessing but it's likely a Rochester or a Holley. carb? Stick with a Holley as Quadrajets are pure-D junk.and hard to tune properly. Carter/Eldlebrocks are okay, if that is what you have.

 

In addition to what oilcan henry suggested, you might want to check how addl oil could be getting into the engine. Have seen where a defective trans vacuum modulator would leak trans fluid into the engine and you could get rid of mosquitoes with that white smoke. The plugs don't show the usual color for coolant getting into the combustion chamber. Hope you don't mind my observations..

 

These plugs have maybe an hour of run time on them that's why I said they look rough but I forgot to mention that previously. Have you ever seen a carb gasket allow for white smoke if the carb is leaking gas?

 

Thanks for the input man! All observations welcome, its a sbc to a SM465 so I am 99% positive theres no way for additional oil to get from the trans to the engine but this is my first rebuild so I could be wrong!

 

Not that I can recall Blake,