Throttle Body or Carburator?

I recently purchased a '91 GMC 1 ton crew cab truck to pull our 22' Fifth Wheel trailer with the whole family in the truck. 350 automatic 3 speed plus overdrive. Its a good solution, except for the fuel consumption! The computer must have 'moods', because sometimes its fairly fuel efficient , and just plain awful at other times - under the same driving conditions.

My first observation is that this transmission really likes to keep the motor spinning, and a 350 is a lot of motor to spin. I'll install a tach sometime to get some factual information.

We are planning to manufacture our own dual exhaust conversion by cutting and blocking the crossover and going to the back with another custom made 3" exhaust system (catalytic converter and muffler, etc).

A friend has 'almost' persuaded me to remove the manifold and throttle body and replace it with a 4 barrel carburetor. This almost seems sensible to me, but I would like some confirmation from this group. Would the right carburetor increase the performance and fuel economy, or should I stay with the throttle body?

Reply to
news.datemas.de
Loading thread data ...

I'd be leary of the conversion myself. First you can get a lot of difference in milage by where you get your gas from, The time of year, ETC! There are many different factors to add in that can alter your vehicles milage. The dual exhaust you are thinking of may help. But if your going to be loading your truck. You may want to leave a crosover tube between the two. That will help keep the system balanced. Also your ignition may be run off the sensors. If you change to a carborator. You may need to change the ignition to an older HEI type. I've found in my 96 that if everything is in sinc. I can get from 14 on the city to 19 on the highway. Which in a 7.4L SFI (454) isn't to bad. My dad had a same truck with the 5.7L TBI (350). He got 15 in the city and 21 on the highway. But his milage changed alot during traveling depending on where he was and how he was driving. So I wouldn't worry to much about the carb idea. Look into improving the basics (Tune-up, Tire size & Inflation, Filters,Etc! ) first and see where that takes you. Then pay attention to where you get your fuel! and even what days you get it. My favorite station gets their fuel on Tuesdays. So Wednesday evening I go fill up. Seems the fresher you get after the garbage settles works best for my tank! (Just some thoughts!)

Reply to
Daveman

I wouldn't try to put a carb on it, just make sure that it is in tune, running properly and slow down.

Reply to
Sigwings

Taking the TB out might also screw up the computer so that your gauges won't read out correctly - just a thought.

Ken

Reply to
NapalmHeart

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.