i have a 1981 corvette and im lookin to replace the carb soon because its getting a lil weak. i want to replace it with a 650cfm carb. anybody know of a good brand and model number that will fit in my car without heavy modification? thanks

Kevin

 

Why not go w/ a holley vacuum secondary? Upgrade the intake while you're at it. Get a square bore or dual pattern.

-Steve

 

I went with an Edelbrock 600 cfm on my '80 2 years ago and love it.

 

You might check out the Edelbrock 190X series - pick the one that is for your year range. These are new carbs based on the Rochester carb (same as what you have now). Your other changes (air cleaner, vac lines, etc) will be minimal if you stick with the same kind you are pulling off. Of course, you have some electronic connections to your carb that I dont have. Check the Edelbrock web site for more info to see if this is a good option for you. As I recall, 1901 is for the early motors. A 1902 came with my car and it is very nice.

 

Ummm...nobody has addressed the issue of the '81 being computer controlled. Unless your car has already been altered, there's more to it than simply swapping the carb.

In any case, if the car is getting a "lil weak" there's other issues at play. The carb is often blamed, but is actually the least of your problems!

 

Page is right: 1981 is an ECM-controlled carb, and it cannot be replaced with a standard carb unless you plan on eliminating all your ECM controls to the carb system. You need to retain your existing carb if you want to keep your ECM controls intact.

Also, keep in mind that your stock intake manifold will only accept a spread bore Q-Jet type carb. If you want to change over to a Holley/BG type system, you have to swap your intake manifiold in addition to eliminating all computer controls.

If your Vette is stock or near stock, I suggest you do a good rebuild on your original ECM Q-Jet and do a good tuning of the car to bring back the performance.

 

a lot! (Hi Page, hope the winter weather isn't too bitter where you are

 

Hi Paul! What's "winter"?

 

I just purchased a 81 Formula that had a rebuilt q-jet on it, computer controlled. I believe may computer was bad as it would idle and run all over the place. I replaced the carb with a edelbrock 1406 and replaced the dist also. No more computer control. Runs much better. I do have the rebuilt carb if you just have to have one. I took it off and took the top off to look for trash. I found none but didn't get something back right and fuel came out the top. Probably an easy fix if you know something about carbs. Pesonally I'd swap the carb and dist. If you want the one I've got, I'll let ya have it cheap as I also have the original.

 

As Lars said. If you've still got the confuser hooked up then the workshop manual has a good section on checking/setting up the E4ME.

(Hi Lars: any idea how long AFR take to deliver heads???).

It's that time of year when the local authorities, out of spite, spread tons & tons of salt over the roads
It's not bad at all here (global warming? Bring it on!) but parts of Utah are only a couple of degrees warmer than a deep freeze I used to work in


Brooksman,
If Kevin doesn't want it, what sort of price do you want for it? More importantly, is the thread on the fuel inlet OK (the large thread where the fuel filter sits) & is it a 17081228?

 

Fuel filter threads are ok. Where would the number be located. My Formula has a chevy 305 so I am assuming it is close if not the same carb.

 

Good question! It's been a while since I looked at it but I think it's on the rear of the drivers side? I'll have a look at mine tonight & get back to you tomorrow

 

i'm running an RPM air gap w/ a demon carb on my 81. the only thing the computer does anymore is lock up the torque converter.

 

Glad you mentioned that as this carb came off of a 4-speed car. Don't know if that makes a difference or not.

 

You've just got to decide if you want to troubleshoot electrons (stock) or vaccuum (1980 style set-up).

Don't duplicate the actions of the mechanical "genius" I got Fast81 from.................................swi tched the carb, left the electronic distributor in -- No wonder it didn't run too well


I've got the entire Edlebrock Performer Power Package (Carb, Intake [nonEGR], Cam & lifters) that came off Fast81 when she went for a rebuild.

Now running RPM AIRGAP, XE268, and the Projection FI that's been on duty for a few years.

 

how did you set up so the convertor is the only thing controlled by computer? what did you replace?

 

I am in the same boat as some others. When my 81 refused to run anymore, I bought a Holley carb and intake and got myself back on the road quickly. Now I know that it has never been right since doing that, but at the time, it ran with the Holley and got me to and from work everyday for many years.

Now I feel I want to go back to my stock set up and make the computer do more of the work for me. With the E4ME factory presets, blind rivets, hidden controls, etc., what can accually be done to rebuild a E4ME other than clean it top to bottom? Mine has been sitting up with its intake for years in a box.

I agree on one thing, the stock distributor and a replacement carb do not mix very well. It works, but not really well for sure.

Thanks.

 

My 81 i have change everything to Edelbrock proformer(heads,cam lifters.intake and carb) also changed the distrubitor. Took the computer out as I have a 4 speed. It seams to run great.

 

Brooksman,
Sorry it's taken a while, didn't get to see the carb until this morning. Right then, the number is on the rear of the d.side of the carb, just behind the throttle cable setup. There's a vertical rib on the side of the carb (reinforcement for an air horn screw?) & the number is written vertically on the front face of the rib. There's another number immediately below it, but I haven't a clue what it means. If you stand facing the throttle cable bracket & look to the right you should see the numbers.
Quite a lot can be done. You can remove the blanking plugs so that you can get at the adjustments. You'll be able to set the rich & lean stops on the primaries (the dancing needles), adjust the idle air bleed valve, set the idle mixture, check/set the float level, check/adjust the TPS sensor, set the AV spring tension & adjust the secondaries as you would for a non-computer controlled Q-jet. You'll need an AVO & a simple test harness for setting the TPS & you can buy a set of cheap gauges for the rich/lean stop adjustments. Apparently they are easy to get hold of in the US, but I had to make my own as they're not available here. What you really need is Doug Roe's book on the Q-jet as it's got a bit of info on the E4ME or, preferably, the shop manual for an L81 as it's got an entire section on the carb & another on the confuser. Also, there should be a whole bundle of stuff in the archives. If you can get hold of Dallanex he should be able to help you out with where to get the gauges & TPS harness. A dwell meter can be used to set up the rich/lean stops after initial setup, but you'll need an analogue one with a 6cyl scale.
You don't need the computer if the TCC lockup is the only function left for it. All the computer does is to earth a wire so that a relay trips & lets current flow through the TCC solenoid, giving lockup. The wire that gets earthed can be found under the center console (behind the left cover on mine). It's a black/tan wire and has a test connector built into it in the region of the defog switch. All the confuser does is switch this wire to earth to enable lockup.
With both the carb & dist swapped out the car should run really well (as it'd be like any earlier C3). Swapping out just the carb or just the dist could cause problems as the confuser (ECU) may start complaining.
Dean, I had an excellent holiday in Thailand a couple of years ago & finished off with a week in Phuket for some sun sea & cheap booze. But it rained all week! Anyway, we did the obligatory boat trip to "James Bond Island" & on the way back a squall hit us. People started getting sea-sick, so what did the Thai crew do? They played a video on the large screen of big cats (lions, leopards, cheetas, etc) chasing prey & ripping their throats out. Hilarious There were all these tourists looking green & sick & they were being shown a video of wilderbeast running along with their stomachs ripped out & entrails spread all over the ground, bison having their throats ripped out & various other close up views of carnage. All in glorious technicolor The Thai sense of humour is right up my street!

 

I found this number in kind of a circular patern in the same location you spoke of. 17070839. Must be a little different.