Junior Member
on my 84 gmc with a 350/300 crate engine. when I installed this motor I installed a edelbrock quad jet (new). I have never been real happy with as I get terrible mileage with it on the truck. truck runs decent and passes emisson test easily. but I was wondering if there isnt a better carb. I was looking at the edelbrock carter 600cfm or a road deamon. any idea . thanks

mike reeh

Senior Member
oooh dixie1 was right on the money.. Holley projection would have been bitchin.

as for the edelbrock qjet its and excellent carb, and you're really not going to get any better mileage with anything else unless the next carb is tuned better for the motor. qjets are your best bet for mileage, with the small primaries.. the trick and tough part is to keep your foot out of the secondaries :/ .... You might want to look into having the carb tuned professionally by a shop with the equipment, or install an 02 sensor and guage, and do it yourself.. IMO, trial and error method is out of the question. Im on my way right now to my buddies house to weld in my O2 sensor.. got the guage (autometer A/F ratio) hooked up already.. my first time with this idea but i'll let you all know how it goes.. good luck

mike reeh


You all are answering the same kind of question I have. I too like Roland26 am dissapointed with my mileage. I have a '78 with a 400 and turbo 350. When I bought the truck, it came with an Edelbrock high rise intake and Edelbrock carb. I was thinking of putting on a Holley carb (quadrajet) for better mileage. But maybe from what you're saying, it won't make that much difference. Maybe I'll have to get used to barely breaking the double digits on mileage.

Captkaos Veteran
The best carb for gas mileage is a Quadrajet. All the Holley hybrids I have ever had get worse gas mileage. For the Performer by Edelbrock, I have no experience, but a few friends have them and like it. One of those is He has a tech page on adjusting carbs.

Unless it is Holleys MPI ProJection (Not TBI) I wouldn't waste the money. AND would the $1300 cost merrit the gains. Doubt it.

Power mad

Hey Chris.
Thanks for that site, It has links to other forums that are realy cool. And that first one had a topic on transmision problems that is right on the money with the ones that other folks on this foum have.

mike reeh

Senior Member
For most peoples application the mpi projection would be a waste of money. for half of that 1300 dollar price tag the tbi projection is awesome. just the change in throttle response alone (over carbed) is worth the extra couple hundred bucks, not to mention ease of cold starts, tuneability, emissions/mileage, coolness factor, etc.

for a truck, especially a daily driver, i would, any day of the week, buy a tbi projection. were not talking about muscle cars or really high hp motors here. most trucks are for towing and projection is exceptional for that type of use.

heck in the mid 90s when gm started using mpi it was nothing compared the the tbi 350's of a couple years before it.


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