What's the right carb with my engine setup?

[slowestmonte]

So right now I have an 88 Monte Carlo LS with the LG4 305. It has a stock engine, but it has an Accel vacuum advance distributor, Weiand Speed Warrior high rise dual plane intake, and a Holley 1850 carb. The Holley was supposedly rebuilt before I bought it, but it has all sorts of problems with the secondaries, plus it leaks fuel. Talk about a scam. I'm also getting like 6 or so MPG in town, which I assume is because of the carb. The timing is set correctly by the way. I was wondering if I should go for a 500cfm edelbrock or a 600cfm. I'm trying to get semi decent mileage (I know I'm not going to be getting huge numbers, but upper teens on the highway would be nice). I assumed the 500cfm would give better mileage, but would it make the car stumble with the intake that it has?

 

[axisg]

my vote would be back to a 70's Qjet and track down an air cleaner setup from a Monte SS ( they drew cold air from factory ). Small primaries and fresh air will net economy gains as longs as you keep your foot out of it

 

[Wageslave]

My vote goes to an Edelbrock 1406. 600 cfm should be plenty for a 305 with a little room to grow in the future.

I get 15.5 out of a 350 with no overdrive. You should be seeing 16 or better with about any properly functioning carb though.

That high rise intake seems out of place on this engine. What other mods does this engine have?

 

[TURNA]

Edelbrock 1406 since u have the square bore intake

or a Proform 600 since the linkage will bolt up just like the Holley

 

[MrSony]

Since you already have a square bore intake, I recommend learning how to rebuild a holley. Carb rebuilding is a valuable but fleeting skill. Ideally, I'd get a dual pattern intake and run a 75+ non electronic quadrajet.

 

[Clone TIE Pilot]

Qjet. Sadly, your car sounds like the typical G body basketcase. Some PO thinks removing the stock E4ME will magically makes his car faster, only it ends up running worse so he dumps it on a unsuspecting buyer. Seen it over and over. Who knows what else is wrong as PO can do very strange and bad things to these cars than can be hard to detect.

 

[slowestmonte]

I'm the one who replaced the intake and all, but I didn't do it to make the car faster. The original carb was shot, the distributor needed a new cap and rotor anyways, and the car endlessly dieseled. I tried adjusting timing and spent hours tuning the carb, but when I stripped out the coolant line fitting at the back of the manifold I just decided to go all out. And I would be going back to a rochester, if it werent for the fact that I already have a brand new square bore intake on it. My question was more on choosing between the 500cfm and 600cfm models.

 

[fleming442]

I have seen very few that are happy with the Ebrock carbs, especially in a performance application. You can rebuild a Holley; it's cheap and easy!
Now, as far as that intake and the rest, <Naughty by Nature> well, that's not so simple.

 

[pontiacgp]

for a stock 305 a 500 cfm would work fine. A 305 at 6000 rpm needs less than a 500 cfm carb. When we ran in the super stock division we used the GM 602 crate which is a 350 and we were limited to a holley 500 cfm 2 barrel. The chip we had to run was a 6200 rpm and that carb never ran out of gas or power. That holley was a race version but it was only a 500 cfm. That being said I do not like holley carbs for the street. I have a Quadrajet with an adapter to fit my carb on a squarebore vortec intake. With my 355 I can get over 25 mph on the highway.

http://www.carburetion.com/calc.asp

 

[slowestmonte]

Wow, I didn't realize you could get upwards of 25 with a rochester. Maybe I'll have to make the old manifold work and get a pre computer rochester.