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Jan 19, 2022 | 04:15 PM

81C3BUILT

Thread Starter

Heel & Toe

Joined: Jan 2022

Posts: 16

Likes: 1

From: WESTCHESTER ILLINOIS

More gas from e4me

I'm keeping my stock electronic carburetor, computer ,knock sensor, O2 sensor ,but building up the engine on my 81 C3. I have a jet stage two chip that will take care of the O2 reading, IT WILL ALSO take care of advancing my timing for optimum performance , weaken the knock sensors sensitivity, I have high flow Vortecs with 2.02 valves 64cc and 185cc and other machined upgrades, a decent cam CL12 – 242–2 comp cam flat tappet lifters. Not too much lope but enough 110 lobe sep. Obviously headers with straight through exhaust pipes to Flowmaster 40 series...What I really need to know is what the stock main jet sizes and and what size I should go to obviously it will be hit and miss but if anyone has already had this dilemma what size did you go with. And are there any other tricks to perform on this carb, I know everyone is thinking dump computer, but it's just not my style. And i am determined to make this car go fast and remain somewhat stock on the electronic side..Thanks to all that pitch in. I am grateful for any help...Lou 81 c3 red/silver

Jan 19, 2022 | 06:03 PM

Engage

Racer

Joined: Oct 2001

Posts: 474

Likes: 64

From: Portage La Prairie Manitoba

If you want it to go fast.... drop in a 427 crate engine.You are going to beat yourself to death trying to get that engine to perform!

Jan 19, 2022 | 06:42 PM

derekderek

Race Director

Joined: Jul 2015

Posts: 13,082

Likes: 3,399

From: SW Florida.

that setup was a bad idea 41 years ago. there is a reason it was done in 1 year. do not waste your time tryna get a 40 year old ecm that is the absolute oldest slowest dumbest ecm ever put in a car to perform. it can barely understand idle.

Jan 19, 2022 | 07:04 PM

resdoggie

Had a 1976 L-82, 4-sp

Joined: Mar 2011

Posts: 5,338

Likes: 1,213

From: Some days your the dog and some days your the hydrant.

Royal Canadian Navy

Good advice so far.

Jan 19, 2022 | 07:58 PM

calwldlife

Team Owner

Joined: Jan 2007

Posts: 53,648

Likes: 878

From: Southern Cal Ca

St. Jude Donor '22

the main jets are fixed. the needles/rods may be changed but it is pointless considering the ecm controls the mixture.
You can adjust how far the needle goes into the jet at idle/lean and how far out the needle/rod comes out of the jet. full rich under wide open throttle.
There are adjustable stops.

The secondaries are normal quad carb pieces.
You can change the rods and hangars for secondary use.

Jan 20, 2022 | 06:03 AM

derekderek

Race Director

Joined: Jul 2015

Posts: 13,082

Likes: 3,399

From: SW Florida.

and as soon as that sad excuse for an ecm sees the O2 reading it will start pulsing the needles faster or slower to set the O2 where it thinks it should be. if you have a chip that "takes care" of the O2 readings you have basically shut off closed loop and it is no longer an electronically controlled carb anyway. buy an older q-jet or holley and sell that e4me stuff on ebay.

Jan 20, 2022 | 10:32 AM

Fly skids up!

Melting Slicks

Joined: May 2021

Posts: 2,271

Likes: 1,316

From: Fleming Island, FL

Okay, here's my 2 cents. People always bad mouth what they don't understand. The Computer controlled command system was a good system. It wasn't a 1 Year thing, more like 10, on both 2 and 4 barrel carburetors. The last time I opened up one of those non electronic quad-a-pottys the jets weren't removable ether. The only thing that the CCC system controls is the Cruise mixture. WOT A/F is still adjusted by swapping the rods. Now the only thing is you're stuck with a less than optimal spark timing and that hypertension chip really not going to help much.