Old RV gas mileage

[skyactiv]

Saw this RV on CL and am wondering what the gas mileage would be. Has a 440 Mopar. Back when it was new, the speed limit was 55 MPH and gas had no ethanol in it.
Wonder what it get today doing 70 MPH with todays E10 gasoline? I don't want to buy it, I'm just curious.

1979 Avco - rvs - by owner - vehicle automotive sale

1979 Avco motorhome, dodge 440 engine, 32', tag axle, sleeps 6, rear bath, needs work

columbus.craigslist.org

 

[RooflessVW]

I'd say 1-2GPM.

 

[MParr]

To get it going and make it E10 ready would be costly.

 

[AlienBug]

We had a slightly smaller motor home in the late 1980s. With a 454 it would get 11-13mpg at best.

 

[ls1mike]

I had a 24 foot class A 454. 9 ish is what I got. 88 Fleetwood Southwind

 

[mcdonnell]

id say run away how much would it cost to put tires on that thing? The only way that would get 10 to 11 mpg is parked. my 2000 caddy Deville gets 9mpg . heavy foot. sorry i just reread and saw you weren't going to buy thank god.

 

[AZjeff]

The question is what mileage will the tow vehicle get that will tow it to where ever it's going to be a camp. Being molded fiberglass it may not have leaks. It will have rodents.

 

[supton]

I wonder if it would do 70? I mean, it might be a 440, but look at what it has to push? Then again, a 440 isn't that hard to hop up.

No experience but I'm in the camp that would be shocked if it could do double-digits.

Wouldn't an E10 "conversion" just be refreshing the rubber fuel lines and perhaps a carb replacement? I thought it was the residue left behind from evaporating off, and some damage to rubber bits, that was the problem. E10 has been around for a while, so I'd think any rehab on an older motor might benefit from a new carb or a proper at-home rebuild (using quality parts).

Anyhow. On youtube there's someone who LS-swapped a Winnebago. I think they pulled a 440? and swapped in a turbo 6.0 LS.

 

[Kruse]

I used to have a Ramcharger with a 318 that got 8 mpg no matter what you did to it. For this vehicle, you’d be lucky to get half that.

 

[earlyre]

I'm gonna say you'd be lucky to to get double digits....
the pics have me flashing back to the EARLY roadkill eps where they first built General Mayhem...with a 440 from a Motorhome.

 

[IndyIan]

My uncle got a single axle version of this and it was getting like 5 mpg, and not at 70 either... They sold it shortly and travelled around N.A. with a tdi Jetta and a A frame trailer getting near 30mpg for a few summers.

 

[pghvolvo]

That beast would be lucky to see 8 or even 9 mpg at anything over 60 mph.

 

[samven]

It will never see double digits unless the whole trip is downhill. The Ford 6.8L in a modern 26' RV gets about 9 avg, my Chevy 6.0 L Vortec gets 10.7 if I nurse it. That thing is a 7.3 L and probably has a very low rear end, my guess would be 6-7 mpg on 10% ethanol if your careful.

 

[mcdonnell]

440 with the carter thermo quad.

WikiFoundry

avcomotorhomeenthusiasts.wikifoundry.com

last post was 2015. all bankrupt.

 

[Nick1994]

My dad has a 99' Fleetwood Flair 30' RV, has a 454 Chevy in it. Fuel injected and gets maybe 8 mpg on a good day.

That one? Probably 5.

 

[spasm3]

9

But really it does not matter. I get 10-11 towing my travel trailer.

 

[RhondaHonda]

5-7 at 70 mph is my guess since that’s the speed you asked about. Maybe 9 at 55-60 mph.

 

[Chris142]

5-7 mpg max. That 440 will run circles around a 454 or 460 though.

 

[Rhymingmechanic]

When I was working at a gas station around 1990, I asked a guy with a motor home smaller than that about his mileage. This was a more square-shaped one and it had a 440. He said either 5 or 7 mpg.

 

[02SE]

I've been around several of those. I'd figure on 4-7 mpg.