Fuel Efficient Carb

[70chall440]

I know that some people are emotional about carbs and I agree that they have and do work but I do not ever intend to run another one on any car if I can help it. Properly set up EFI with a good electrical system is hard to beat. I will say that adjusting timing and fuel with a laptop is an interesting experience.

 

[i_taz]

I just put a Thermoquad on a 440 and am happy with it. Haven't checked mileage yet but like all spreadbore design's fuel economy was the objective. Wouldn't a 360 come with a spreadbore intake ?

 

[Chryco Psycho]

340s & 360s came with spreadbore intakes

 

[shebacat]

1974 Challenger, 360, 518OD, 3:23 stock thermoquad .I just did three road test and I'm getting 21.6 mpg highway that's imperial gallons 2100 rpm at 60mph.

 

[Chryco Psycho]

That is Decent !

 

[fasjac]

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 also get around 15-16 per gallon
on the highway in 5th with 500 stroker six pack. That’s only cruising at 65-70, 2300rpm though. Mat it and it’s single digits.

 

[budascuda]

I also get around 15-16 per gallon
on the highway in 5th with 500 stroker six pack. That’s only cruising at 65-70, 2300rpm though. Mat it and it’s single digits.

Yeah, single digit fuel economy, but double digit fun........

 

[fasjac]

Yeah, single digit fuel economy, but double digit fun........

Single digit mileage is big fun, just need the real estate

 

[money pit]

I know that some people are emotional about carbs and I agree that they have and do work but I do not ever intend to run another one on any car if I can help it. Properly set up EFI with a good electrical system is hard to beat. I will say that adjusting timing and fuel with a laptop is an interesting experience.

What EFI are you using. I hear good and bad about FiTech and Holley. Thanks

 

[70chall440]

At the time I wrote that I had a Fitech system on a 52 Dodge with a 56 Desoto Hemi in it, but I still have 2 EFI 6 pack systems, one running a FAST EZ system and the other is using a Holley HP system plus I have a Holley Terminator Max Hemi system for my 5.7 that will be going into my 71 Charger.

 

[money pit]

At the time I wrote that I had a Fitech system on a 52 Dodge with a 56 Desoto Hemi in it, but I still have 2 EFI 6 pack systems, one running a FAST EZ system and the other is using a Holley HP system plus I have a Holley Terminator Max Hemi system for my 5.7 that will be going into my 71 Charger.

Thanks.

 

[money pit]

I just put a Thermoquad on a 440 and am happy with it. Haven't checked mileage yet but like all spreadbore design's fuel economy was the objective. Wouldn't a 360 come with a spreadbore intake ?

When I bought the engine it didn't have an intake manifold. The sell gave me a Performer intake manifold. Will this work with a Thermoquad?

 

[Cuda416]

When I bought the engine it didn't have an intake manifold. The sell gave me a Performer intake manifold. Will this work with a Thermoquad?

it it's a spread bore (secondary larger than the primaries). You can also get spacers/adapters that go from spread to square.

 

[money pit]

it it's a spread bore (secondary larger than the primaries). You can also get spacers/adapters that go from spread to square.

Thanks.

 

[money pit]

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

What kind of a cam are you talking about? A stock cam? When I had the engine rebulit the builder said he was going to put an RV cam for more torque. Could this be a reason for poor MPG?

 

[terrywalker]

My 71 Challenger convertible is a completely stock 340 with the original Thermoquad carb and has the original 4 speed and 3.23 sure-grip rear. On the highway at 60mph, I have consistently gotten 21-22mpg if I keep my foot out of it. Just nice easy cruising. City driving, about 13-14 mpg easy driving.
Terry W.