1971 chevy c10-carburetors - Car Troubleshooting


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1971 chevy c10-carburetors

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Hutch
New User

Apr 26, 2008, 3:42 PM

Post #1 of 4 (4862 views)

1971 chevy c10-carburetors	Sign In

I have a 1971 Chevrolet c10 pickup. a friend of mine told me that it would improve performance and mpg if I changed it from a 2bbl carburetor to a 4 bbl carburetor. I have been told by another person that you cannot switch from 2 to 4 without extensive engine work. can anyone clear this up? also is there a difference between an automatic and electric choke?

Hutch

Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Apr 26, 2008, 4:09 PM

Post #2 of 4 (4857 views)

Re: 1971 chevy c10-carburetors	Sign In

IMO to get full benefit from a 4v carb you would get the correct intake manifold. I've owned plenty of Chev V8s of the era and the 2v (2bbl as you wrote) actually got better gas mileage than the four barrel ones but I was young then and would have the things wide open for power more than in these days. In essence the 4 is just using 2 when not pushed hard. Four would have more power than the two in this if you wanted that.

Also for that vintage the rest of the engine that was ordered with a 4v would likely be different for more performance.

In short - just drive gently and that is about the best you'll do and save the headaches of the switchover and a more complicated carb,

T

Hutch
New User

Apr 26, 2008, 4:13 PM

Post #3 of 4 (4855 views)

Re: 1971 chevy c10-carburetors	Sign In

thanks for the help Tom, I also was wondering about the difference in an automatic and electric choke (if there is a difference) and also the difference in automatic versus manual choke.

Hutch

Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Apr 26, 2008, 5:17 PM

Post #4 of 4 (4850 views)

Re: 1971 chevy c10-carburetors	Sign In

Automatic vs manual choke in 1971 all were automatic TMK. They make kits for when the auto ones don't work properly which is pulling a cable but trust me it's worth fixing the auto choke as the kit ones become a one person knows how to do it exactly right problem right away vs manual ones that were designed to be manual.

If it works you could adjust it to shut off quicker and possibly save some gas if that's what you want to do. Not a huge difference possible if it works properly it is about as efficient as is practical. 1971 should have used exhaust heat to shut the choke off and that was a problem area to keep working well or choke would hang on forever and use lots too much gas - and foul plugs etc.

Seems like you and the rest of the world are aiming for the best possible MPG. Almost everything ever built with the original designs is about the best it can be. Don't be fooled in some snake oil products.

If an engine is kept running well and in perfect tune then the MPGs are optimized by..........

*Inflate tires to proper or max allowed for the vehicle. Check them often.
*Avoid accellerating quickly and plan coasting to stops rather than last second braking harder.
*Plain drive gently and don't change speeds abruptly.
*Take all items out that you don't need - like carrying tons of stuff that you don't need every day. You are paying to move the weight all the time.
*Drive slower on highways. It's remarkable how much better gas mileage you get at 55-60 vs 70-80 mph. Many folks recall the embargo of 1973 when the US got oil shut off on us and President Nixon quickly made it a US law that the max speed limit was 50 MPH which was later changed to 55 with way too many complaints of just 50.
*If a standard shift get into the high gear on time but don't "lug" the engine over it.

Note: The 2 bbl carbs of 1971 were meant for using "regular" gas. Regular depending on the rating system could have been 93 octane by today's way! There was nothing so low as 87 which is called "regular" now. High performance engines used up to 98 octane and 105 was sold by Sunoco! We forget! This vintage can run on 87 if you don't push it - if you do hear crackling knocks or ping then you should check that engine carbon is not built up and you can de-tune for lower octane a bit - mostly retarding the timing to match the octane you wish. Some will lose MPG de-tuning and not be cost efficient vs the higher octane fuel.

Fair guess as to what you should expect: 12-14 around town and 18-19 or so steady on HWY driving for a V8 truck,

T

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