4bbl... better milage?

[Possum]

I got a 351M with a stock 2bbl carb on it, I've been looking at putting a Holley 4bbl on it, from the looks of it-the front two ports on the 4bbl are actually smaller than the 2bbl ports, and I've been told that the back two ports(which are bigger) only open up when you really get into the throttle, so wouldn't that mean that at normal hiway driving the 4bbl would get better gas milage than the 2bbl?

 

[LEB Ben]

You're correct...typically the primaries are smaller. So in theory, it should get better mpg's, but as you stated, that is determined on how well you keep your foot out of it. Then you'll get into volumetric efficiency and whatnot whe trying to determine which 4bbl will yield the best results for you.

 

[1985 Ford F-150]

Also depends on the carb as to the size of the primaries and secondaries ie quadrajet vs edelbrock or holley.

 

[Possum]

The 4bbl I was comparing the 2bbl to was an edelbrock, but i wanna go with a holley, not sure how the holley compares to the edelbrock though

 

[1985 Ford F-150]

Holleys generlly suck for off road but are great for on road. They do make a truck avenger but I have yet to try one. I have a quad on my 410 and it will climb as steep as ya want it to and not power out. Edelbrocks are ok off road but on really steep stuff they will power out as well they are simple compared to holleys so they are easy to rebuild if your not too familiar with carbs.

 

[LEB Ben]

If you're looking for offroad performance...you may as well just go with a reversed Motorcraft 2150. As for Holley's...don't let Dan fool you, they're not that bad to rebuild or tune. IMO, the fact that most Holley's offer more tunability over other brands, allows for more people to screw up their carb by twisting this or turning that, when they don't or shouldn't be turned or twisted. My opinion of course. But I do agree that Holley's seem to be a better street carb. I run the street avenger carb on my rigs, and I can slope to 30*, and approach and departure are right at 35*...which isn't the greatest, but not terribly bad.

 

[Possum]

I'm trying to look up a good carb rebuid video, ain't never done no carb work but I got a Motorcraft 4bbl that came off my old 460. May beat buyin a new one

 

[hollenjoe]

Whats up, my 02,

holley= more performance but a pain to tune
edelbrock=less performance but a child can easily tune it, is more reliable and can go for a lot longer without any servicing

Joe

 

[money_pit]

Holleys generlly suck for off road but are great for on road. They do make a truck avenger but I have yet to try one. I have a quad on my 410 and it will climb as steep as ya want it to and not power out. Edelbrocks are ok off road but on really steep stuff they will power out as well they are simple compared to holleys so they are easy to rebuild if your not too familiar with carbs.

"Holleys generlly suck for off road" That is complete malicious BS.