Fuel Efficient Carb

[money pit]

I have a 360 with auto trans. I'm not sure what rear end gears I have. I have a 4 barrel Edelbrock carb. Is there such a thing as a fuel efficient carb? or should I be looking for higher gears or overdrive to get better gas mileage? I'm planning on changing to a 8 3/4 rear end with 3.23 gears .I currently get 9.5 miles a gallon, mostly freeway driving. The RPMs are about 2700 at 65 mph. Thanks

 

[Chryco Psycho]

EFI will be the most efficient & the cost is comparable to a carb now .
Eddys are the Least tunable carbs , I like using the Proform carbs great value & performance , I have been ableto get over 20 MPG on 440s & 18 MPG with a 512 strokers , Overdrive will help also to keep the revs down at high speeds .

 

[budascuda]

EFI will be the most efficient & the cost is comparable to a carb now .
Eddys are the Least tunable carbs , I like using the Proform carbs great value & performance , I have been ableto get over 20 MPG on 440s & 18 MPG with a 512 strokers , Overdrive will help also to keep the revs down at high speeds .

Can you even get 20mpg from an EFI 440?

 

[Chryco Psycho]

With the right cam , porting , intake & heads gearing I have been able to

 

[moparleo]

............................Click on these tuning links.
Tuning the Edelbrock AVS Carburetor
Edelbrock.com: Edelbrock Product Frequently Asked Questions

 

[Bobby Sixkiller]

You won’t believe me but here goes. 74 challenger. 440/727. Low compression engine with a six pack cam. Shorty headers. Holley street demon. 3.23 gears. 17 on the highway at 65. About 8 around town. 235/70/15 tires

 

[budascuda]

Everything is hi performance except the compression!
Very interesting, how did you come with that combo?
I don't know much about high performance engines, but isn't your setup counter intuitive?

 

[Bobby Sixkiller]

It’s a rv engine with a cam carb and headers. Seems to run pretty decent. Basically a really cheap used parts combo. Only thing new engine wise was gaskets and carb.

 

[Chryco Psycho]

why would I not believe it 17 MPG is totally possible cruising

 

[rklein71]

I got 17 mph in my 440+6 on the highway just after I blew up my 3.55 gear set. I got a 2.73 (i think) from a Dodge Monaco. I spent 50 bucks on it, 1984, just before transferring in the military from Florida to Idaho. Best 50 bucks I ever spent. My car would fly down the highway!

 

[budascuda]

It's grand when you can make do with what's on hand and still have great results.
I love cowboying it!

 

[money pit]

EFI will be the most efficient & the cost is comparable to a carb now .
Eddys are the Least tunable carbs , I like using the Proform carbs great value & performance , I have been ableto get over 20 MPG on 440s & 18 MPG with a 512 strokers , Overdrive will help also to keep the revs down at high speeds .

I've been doing a lot of research on EFI. They have Face book pages for the FiTech, Holley Sniper, and others. I've also checked a lot of blogs online. Both have a lot of problems technically and customer service so I'm steering away from EFI. I figure if the car didn't come with EFI, stay away from it. Who makes the Proform carb? Thanks.

 

[money pit]

You won’t believe me but here goes. 74 challenger. 440/727. Low compression engine with a six pack cam. Shorty headers. Holley street demon. 3.23 gears. 17 on the highway at 65. About 8 around town. 235/70/15 tires

Wow. Congratulations. I'm not sure what I'm doing wrong. Everything on the 360 is stock, no headers, 2 1/2 in exhaust with turbo mufflers from TTI. Thanks

 

[70chall440]

I've been doing a lot of research on EFI. They have Face book pages for the FiTech, Holley Sniper, and others. I've also checked a lot of blogs online. Both have a lot of problems technically and customer service so I'm steering away from EFI. I figure if the car didn't come with EFI, stay away from it. Who makes the Proform carb? Thanks.

Well the car didn't come with radial tires either....

The vast majority of issues with EFI is poor installation specifically on the electrical side. EFI is certainly not fool proof or perfect but if done correctly will absolutely improve drivability, starting, etc. That doesn't mean its the "be all end all" but it is definitely an improvement over a carb in terms of efficiency.

Like most I grew up using carbs but once i made the change to EFI I never looked back and currently would not run a carb on anything. I am not hating on carbs but I can go out and start any of my classic cars after they have sat for months and they will idle and run without issue.

All that said, to do EFI correctly it does take some work and is not cheap but the payoff is totally worth it as far as I am concerned.

 

[bc3j]

FWIW I’m totally stock with 383HP auto, 26.1” diameter tires, 3.23 8 3/4” rear end and get 8-10 in the city and 13-14 highway. I’m happy with that considering, by design, the fluid coupling in the torque converter is around 92% efficient. So I’m running about 8% higher rpm being an auto. Probably why the auto trans are nicknamed “slush boxes”. Period articles I’ve read put the mpg for the 383HP right where I’m at. Honestly, I’ve never given mpg much thought and have adopted “it is what it is” philosophy. LOL

 

[Chryco Psycho]

Proform is its own company

 

[Huskidrive]

I have a 1970 Challenger 383, 4 speed, 3:23 rear 235/60/15 tires. 10 city miles and 13-14 highway if I don't run hard.....

 

[Crossram413]

Interesting discussion. I don't want to hijack the thread, but....
I'm very interested in EFI and/or overdrive for more relaxed interstate cruising, reliability and decent mileage when not jumping on it. I have a 72 Challenger 340 727. The 340 is from a 1970.
Any opinions or sources of info or wisdom on either or both options? Budget is not unlimited.
Thanks!!!

 

[Ernies]

just installed a new AVS 2 650 cfm on my 360 an it runs great ! they say the new Eddy AVS 2 is the closest you get with carb to fuel injection without all the wire an hassles of computer my 360 has better gas mileage an performance idles great no comparision to the old Eddys

 

[Chryco Psycho]

Crossram , you don't give any information but a 518 will bolt in relatively easily if your car is automatic or the 833 OD version will also bolt in if 4 spd .
There are throttle body EFI systems for not much more than a carb now , Holley & Fitech have decent systems , multiport which I far prefer is a lot more expensive but has significant benefits .