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Discussion Starter #1
Today something strange happened. First I found out not to long ago that my entire El Camino had original parts on it. Every single piece was original other then the Edelbrock intake, the massively oversized 750 cfm Holley double pumper, the flowmastef exhaust with CAT delete and the rims. Since then I've had to put a new front end on it. The entire front end, new alternator and starter and that's about it. Since I have had the car it smokes fairly bad. Enough that I don't go through drive throughs. The carb is way oversized and it's impossible to speed away from anything and it smells of gas and sulfer. Again I have no CAT on my exhaust. Oh yeah. It has a 305 in it. Today I was driving at around 40 mph when all of a sudden it started to sputter like it was running out of gas and ever since then it's feels like it is miss firing, runs like crap, rough as hell idle and it used to be if she sat awhile she was a bit hard to start and on cold days near impossible and when she would start there would be a strong smell of sulfer. But now she is hard to start no matter how long she sits and I smell gas and sulfer stronger than ever. The smell makes me think that the devil is about to pop up in my passenger seat and say. "Love the Elco." 2 of my carb bolts that bolt it to the intake have stripped out but are still holding a little bit. I can't spin them by hand but with a wrench they just keep spinning. I'm afraid I might have dropped a valve. And right before I was getting ready to replace a bunch of the seals and gaskets and reseat the valves and clean them up and go ahead and replace the piston rings and clean up the engine in general. Need some feed back on this. Friends say it's bad gas but the sulfer smell is what's bothering me. Thank you all.
 

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Holley 750 double pumper in most cases is most at home on a big block with a manual trans, if you are towing your car to the local strip. (I know, there will be arguments against this) That sulfer smell usually is caused by a reaction in the converter, are you sure you don't have one? The 750 running rich in a 305 with a converter would cause the sulfur smell. Other than that not sure. I would at least try to find a factory Q-jet intake or even a 2bbl intake with appropriate carbs. That is if you really want to keep the 305. Honestly, the 305 is a workhorse but falls way short if you want something any where near added performance. If you have actually dropped a valve, might be time to decide whether or not replacing with something a bit more fun is in order.

Joe
 

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I have a 305 in my 5th gen also, has a quadrajet and runs its ass off however it does lean out at wide open throttle and higher rpm. that being said when we rebuilt it we left it all completely factory so we can easily rejet it and make it run great on that motor. I agree with 87ls the 750 is too much carb for that motor. I would put a q-jet on it with a good build or find one in a junk yard and spend the $20 and rebuilt it yourself just to see how it affects performance of the vehicle. If you want a good q-jet then yeah I have heard nothing but great things about mountain man's carbs on this site. I would think the cold start could easily be too much fuel from the accelerator pump due to oversized carb, or also an issue with the choke. It also may not be a bad idea to rebuild the 750 and make sure it has the proper size jets in it and the floats are set correctly as well.
As for the bolt issue in the intake the right way to do it is to remove it and tap it out with new threads, replace the intake or "rig it". You should be able to find another intake for cheap on craigslist or ebay.
 

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put some
Heli-Coils <[ link ]
in the stripped intake bolt holes ..
Vacuum leaks will cause all kinds of problems..
.
check the intake bolt to head torque too,,
they can loosen after a few heat cycles,
and cause vacuum leaks and cause it to burn oil, if bad enuff ..
.
what color smoke ??
black or grey/white ??
.
what do the plugs look like ??
 

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put some
Heli-Coils <[ link ]
in the stripped intake bolt holes ..
Vacuum leaks will cause all kinds of problems..
.
check the intake bolt to head torque too,,
they can loosen after a few heat cycles,
and cause vacuum leaks and cause it to burn oil, if bad enuff ..
.
what color smoke ??
black or grey/white ??
.
what do the plugs look like ??
Heli-coils are awesome! X2 on everything else.......... Still, sulfur smell? The only time I have ever smelled that was from a catalytic converter? He says he doesn't have one?

Joe
 

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Discussion Starter #6
Im absolutely positive there is no CC on it. Maybe I have the smell description wrong. I'm having the same issue with my ZX10r with the smell. It's the same smell you get when it's low on oil but my oil is fine. Update. She is back to running fine. Guess she was just acting up or something. I would love to get a Q-Jet. I would even be willing to trade my straight across for a used one. Mine came stock with the 4 bbl but I know it's way to much. That's how I bought it. Honestly I know I made a great choice on it and got a good deal. Trying to decide whether to get a 350 or rebuild the 305. You know they make Sprint car motors out of 305s. I can find 350s all day for around $350 with tranny here in Oklahoma. Maybe I should just invest. Thank you all. I will see about mountain man's carbs I really need one that fits it better. I knowy gas milage would increase and the performance would too.
 

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if the timing is retarded too ??
when the motor gets rich or lean and hot the exhaust does smell different..
gas formula/additives changes with the seasons too..
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the Heli-coils are purty easy..
just try not to go all the way thru the carb flange when drilling and tapping..
it probly doesn't hurt any thing, but you'll have to catch the chips inside,,
you can make a little aluminum foil cup if you have to..
just cover/tape-up the intake opening and use a vacuum too
suck up the chips from the drill and tap..
 

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After a bit of thinking, I have only one thought. Condensation. Water droplets formed from temp changes and sink to the bottom of the tank. Causes the same symptoms, whether a Holley or a Q-jet. The very reason pilots check fuel samples before taking off, except for them, life is on the line!

Joe
 
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