Rochester 2G Issues

[71GreenJunk]

Hey everyone. I've got a 2-barrel 305 from a '78 Buick Skylark with 80k miles in my '71. The engine runs great but at 65 with my 3.73 gear and 29" tires the engine just stops pulling all together like it's governed to 65 but that's not the case. I suspect it's running lean because richening up the idle made the engine a bit smoother and it does have an open element air cleaner and 2-inch glasspack dual exhaust the dumps in front of the axle. The exhaust is much better than the single exhaust. It's odd the engine is as responsive as it is if the mixture is so far from ideal. I was showing my dad and he suspected the fuel pump. The regulator was set at 5 lb so I bumped it up to 6 which is all I'm getting from the carter pump. Slight improvement but still flatlines at 65. I'm wondering if I don't need larger jets. My dad is thinking the little 2-barrel isn't big enough and isn't able to support the airflow but I know the circle or dirt track guys run pretty big rpm with a 2G.

What do you all think? Has anyone had similar experiences? Any advice is appreciated, I've just had Holley 4-barrels and they're my favorite but I kinda wanna keep the 2-barrel as it's my daily.
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[68Gold/white]

You might check the float level, and raise it maybe 2/32". Most of the stock float level settings are pretty conservative.
78 had to be about the lat year 2G's were used on anything. It would definitely be a little lean if it is stock. Do you have a carb number?

[71GreenJunk]

17058114
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[71GreenJunk]

I'll raise the float when I can get a gasket set. Hard to find carb parts in stores anymore. I'm thinking it's probably a good thing I didn't stick the headers on yet. Yeah, I got luck with it being a 2g, much simpler than the weird dualjet.
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[Wrenchbender Ret]

There are 2 sizes of 2G carbs. The small one was used on the 265-283 & 307 engines. The larger one on the larger engines. I'm not sure about the early 305.
You might try like Gold/White says in checking the float level & raiseing it a little above specks. Try a little larger main jets. I work with a lot of the small 2G carbs in 3 2 barrel setups. They generally are lean. Most come with .055 jets. sometimes you have to go to .062 to get it right. With the 3.73 gears that engine is wound up pretty tight at 65. You really need a taller gear. Have you checked the little filter in the inlet fitting?

[68Gold/white]

I've only seen a couple of stock 305's with 2G's. They were the larger models, and had the hot air chokes.
I had a small 2G on my 67 Bel Air 283. After trying other carbs 2 and 4 barrel's the small 2G was a definite choke down situation even for the 283.
I always wanted to find an unmolested larger 2G intake, carb and air cleaner off of an early 70's 350 or SBC 400. Thought that might have been a good combination.

How well do you know your vehicle? As wrenchbender mentioned check the inlet filter. Check under the vehicle also to see if someone in past may have installed an inline filter between the tank and pump, you never know...

[71GreenJunk]

Had it awhile. I'd like to say I know it pretty good. I did an automatic swap on it before the 307 cracked a head between the valve seats on #3, that's why I swapped in the 305. I'll check for the filter in the carb. I'd imagine my fuel pressure would be higher if it was clogged but ill check. I'm thinking I had 7-9 lb from the pump without dropping the pressure with the regulator on the 307 but now I've just got 6 lb. Carb was a hot air choke but I had a spare Quadrajet that was seized I pulled the electric choke from and plugged the vacuum port in the housing and airhorn. I like the gear, most of the time I'm in town or on the highway so not much interstate, was just concerned about it leaning out if I need to pass someone.
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[geezer#99]

With your set up you're only turning 2800 rpm at 65 mph.
If it's not surging I'd look the other way, back at the distributor.
What's your timing curve like?
How much initial?
Is your vac advance working?

[71GreenJunk]

Hey geezer#99 I think you hit the nail right on the head. Was so excited getting it going again I never checked the advance can. And hadn't thought about it since. Hahaha. Turns out it's got a leak. Boy do I feel silly. Thanks everyone!
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