Sanitizing a 71 C10 with a mishmash of engine parts - The 1947 - Present Chevrolet & GMC Truck Message Board Network

dglaser · 07-14-2010, 05:10 PM

I need some help in figuring how to sanitize a truck that I inherited from a family member.

Basically, it is a 71 C10. It has a THM350 for the tranny.

The engine is a curios case. The truck originally had a 350. However, the engine died and it was replaced by a 305 from a 76 chevy nova. But wait there is more. Evidently, the manifold and carb of the 305 was replaced by a manifold and a two barrel carb off of a 350. I am sure that the carb is off of a 350, I'm not sure about the manifold.

The truck makes terrible gas milage - approx 10 mpg. And is not drivable until the engine gets really warm.

So, would like to replace the manifold and carb with something more suitable.

The problem I have is that up here in the north east, it is really hard to find trucks of this vintage. So I figure I will just have to buy a new manifold and carb.

The goal is to get better gas mileage and improved drive-ability. Improved acceleration would be nice.

Any suggestions on the manifold/carb combination?

-David

BB72CHEVKT · 07-14-2010, 05:16 PM

do not expect much better than 10 mpg's no matter what mods you make

Sinister · 07-14-2010, 05:16 PM

Maybe an Edelbrock 1403 and Performer EPS intake. I wouldn't expect miracles in the MPG department though. These trucks are heavy and have the aerodynamics of a brick.

71tahoe · 07-14-2010, 05:26 PM

With a 305 and 4bbl I have gotten 15 or so on the highway. About the same with a 350 and 250 I6. A 1406 will be OK on a 305 and the electric choke will help on the cold starts.

raycow · 07-15-2010, 01:49 AM

GM made two sizes of 2 barrel carbs (different base bolt patterns) and I believe 350s got the big one. You would get better gas mileage by going to a Q-jet if you have the will power to keep your foot out of the secondaries.

Ray

07-14-2010, 05:10 PM	#1
dglaser Registered User Join Date: Jul 2010 Location: Worcester, ma Posts: 1	Sanitizing a 71 C10 with a mishmash of engine parts I need some help in figuring how to sanitize a truck that I inherited from a family member. Basically, it is a 71 C10. It has a THM350 for the tranny. The engine is a curios case. The truck originally had a 350. However, the engine died and it was replaced by a 305 from a 76 chevy nova. But wait there is more. Evidently, the manifold and carb of the 305 was replaced by a manifold and a two barrel carb off of a 350. I am sure that the carb is off of a 350, I'm not sure about the manifold. The truck makes terrible gas milage - approx 10 mpg. And is not drivable until the engine gets really warm. So, would like to replace the manifold and carb with something more suitable. The problem I have is that up here in the north east, it is really hard to find trucks of this vintage. So I figure I will just have to buy a new manifold and carb. The goal is to get better gas mileage and improved drive-ability. Improved acceleration would be nice. Any suggestions on the manifold/carb combination? -David

07-14-2010, 05:16 PM	#2
BB72CHEVKT Junior Member Join Date: Mar 2007 Location: Hideaway, TX Posts: 4,950	Re: Sanitizing a 71 C10 with a mishmash of engine parts do not expect much better than 10 mpg's no matter what mods you make __________________ 71 Suburban 350/700R4 Project Trixie 72 CHEVY,Highlander,SWB,396,T400

07-14-2010, 05:16 PM	#3
Sinister Between Trucks... Join Date: Mar 2002 Location: Los Angeles, CA. Posts: 3,830	Re: Sanitizing a 71 C10 with a mishmash of engine parts Maybe an Edelbrock 1403 and Performer EPS intake. I wouldn't expect miracles in the MPG department though. These trucks are heavy and have the aerodynamics of a brick. __________________ Beat it to fit, Paint it to match...

07-14-2010, 05:26 PM	#4
71tahoe Registered User Join Date: May 2006 Location: Jonesboro, AR Posts: 916	Re: Sanitizing a 71 C10 with a mishmash of engine parts With a 305 and 4bbl I have gotten 15 or so on the highway. About the same with a 350 and 250 I6. A 1406 will be OK on a 305 and the electric choke will help on the cold starts.

07-15-2010, 01:49 AM	#5
raycow Registered User Join Date: Mar 2003 Location: San Francisco, CA USA Posts: 2,454	Re: Sanitizing a 71 C10 with a mishmash of engine parts GM made two sizes of 2 barrel carbs (different base bolt patterns) and I believe 350s got the big one. You would get better gas mileage by going to a Q-jet if you have the will power to keep your foot out of the secondaries. Ray



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