New member working on a vintage class C RV

[slowmover]

Need to take it over to Hendersons Lineup. Mechanical rolling resistance issues plus steering/handling upgrades are their forte. National reputation. It's the biggest impediment to repeatable FE results at any step of the way.

A set of Doug Thorley Tri-Y headers and non-restrictive single 3.0" mandrel bent exhaust with resonator and chambered muffler. Engine fuel delivery needs to be refined with an O2 sensor on chassis dyno. Stepping up to even simplest TBI would be a benefit (but work with source as RVs have different fuel demand than cars. ) MSD distributor as its far easier to adjust total and initial timing.

A518 trans sounds good. I'd go with Bridgestone Duravis 500 tires. Will balance up with almost no weight and last longer than anything else. Dana 70 rear axle.

See threads by Orbywan. A boat tail would be singular plus effective.

I didn't follow reasoning, but that Streamline TT a better low cost and long term bet than this rattletrap. Wood framing?

An early 70's CAYO Motorvator (Avion) or Silver Streak Class C is a better choice. In which case leave aero alone except air dam, etc. Focus on RR mech issues and upgrade drivetrain. These are far better built. Past plumbing breaks, water damage unlikely.

These and yours are on either the CB300 or MB300 chassis, if memory serves. Traveling with full propane and fresh water is SOP. There won't be any FE gain by doing otherwise, plus they add stability and full practicality. An RV is an RV BECAUSE it has its own heating and power source (propane) plus an excess of water. There's never enough of either. The "benefit" of the coach electric is far less. In fact, it's a want and not a need.

Wall interior water damage is likely on almost all conventional RVs of gen years or more. Pick up a moisture meter with probe and start investigating floor. A long thread on WOODALLS re Dodge motorhomes has been running for years.

What is your projected percentage improvement goal?

[autoarcheologist]

Originally Posted by ksa8907

My parents just bought a very similar rv earlier this year and drove around the country with it over the summer. I think it was a 26' Shasta on a chevy chassis. 350 small block but with a 3 speed no o/d. I think they got around 6mpg.

Aero is going to be easy as cake to improve on that thing but i will say with that age, dont forget to fix the a/c.

I'm already researching a R12 to R134a conversion. Most folks just leave them dead, but again I can't imagine driving down to the Grand Canyon or most anywhere in the summer without A/C these days. It shouldn't be too hard, new o-rings, a new drier, new ports and a charge. If that doesn't work swap out the ancient compressor and try again.

[autoarcheologist]

Originally Posted by MobilOne

What engine is in the camper? 400?, 383?, 360?, 0r 318? My bet is that it is a 360, which was a stroked 318. IIRC, those were carburated engines that tended to carbon up the intake manifold. Those are solid engines. Why not update it with port injection? I don't see why you need to replace the engine. Just update the torque converter with one that locks up (1982 or 83 model ?). What is the rear axle ratio?

It's a 440-3, and I haven't figured out the rear end ratio yet. I need to look it up.

I don't plan to replace the engine, just give it a good tuneup for now. A port injection swap would be fun as well, but I think the 4th speed would be a bigger result and help with noise etc overall as well.

[autoarcheologist]

Originally Posted by slowmover

Need to take it over to Hendersons Lineup. Mechanical rolling resistance issues plus steering/handling upgrades are their forte. National reputation. It's the biggest impediment to repeatable FE results at any step of the way.

A set of Doug Thorley Tri-Y headers and non-restrictive single 3.0" mandrel bent exhaust with resonator and chambered muffler. Engine fuel delivery needs to be refined with an O2 sensor on chassis dyno. Stepping up to even simplest TBI would be a benefit (but work with source as RVs have different fuel demand than cars. ) MSD distributor as its far easier to adjust total and initial timing.

See threads by Orbywan. A boat tail would be singular plus effective.

I didn't follow reasoning, but that Streamline TT a better low cost and long term bet than this rattletrap. Wood framing?

An early 70's CAYO Motorvator (Avion) or Silver Streak Class C is a better choice. In which case leave aero alone except air dam, etc. Focus on RR mech issues and upgrade drivetrain. These are far better built. Past plumbing breaks, water damage unlikely.

These and yours are on either the CB300 or MB300 chassis, if memory serves.

Wall interior water damage is likely on almost all conventional RVs of gen years or more. Pick up a moisture meter with probe and start investigating floor. A long thread on WOODALLS re Dodge motorhomes has been running for years.

What is your projected percentage improvement goal?

Hey Slowmover, honored to have your input again.

We sold the Streamline because we were getting tired of maintaining a trailer and a tow rig, and when we switched from a Tahoe to a Roadmaster as a tow rig the towing wasn't so much fun anymore. We were done with the Roadmaster then got an offer for the Streamline we couldn't pass up and so we let it go.

Let's see, it already has a set of Thorley headers, but duals instead of a single 3". The exhaust is practically new so I'm leaving it alone for now.

A thorough suspension refresh is on the list. A few bushings are new, most have 75k miles on them. It needs shocks, the typical steering box adjustment, will probably just redo the entire front end then get it aligned. I also found a sway bar for it to eliminate some of the sway I felt on the first few drives.

The Clipper is all fiberglass over a wood frame. They don't leak nearly as bad as most 70's aluminum/wood models. I looked at a few, all were total rebuilds. We also wanted something small like this one and loved the looks and fan base the Clippers have so we went for it.

As for % goal I would love to hit 20% once we do the 4-speed transmission. So that would put it right at 9 MPG. Since we'll probably only use it a couple thousand miles a year it doesn't make sense to throw $10k at it, but we'll see how much use it gets and adjust.

[slowmover]

The 440-3 was produced by Chrysler Marine & Industrial. Far better than the competition as it is built to a far higher standard. It has a number of unique parts which do not interchange with standard 440s (mainly to do with engine front drive accessories). Best to do a compression test. Champion plugs

The drivetrain is set up to run the engine at just below peak torque at highway cruise. 27-2800-rpm as I recall. It'll do this for a few hundred thousand miles

I'd love to have one again

Be sure to keep the Thermoquad. Rebuild isn't difficult (leave choke strings alone), and it'll help. Except a hard to adapt GM QJet no other carb will give better performance or FE. As above, a TBI unit will help FE, but not deliver the same power at WOT. We used to add A on electric fuel pump near tank, upstream of mech pump to avoid heat soak.

I'd use Rotella T6 5W-40 oil and Baldwin oil filter. Look into the issue of adding zinc to preserve cam lobes.

[slowmover]

Originally Posted by autoarcheologist

Hey Slowmover, honored to have your input again.

We sold the Streamline because we were getting tired of maintaining a trailer and a tow rig, and when we switched from a Tahoe to a Roadmaster as a tow rig the towing wasn't so much fun anymore. We were done with the Roadmaster then got an offer for the Streamline we couldn't pass up and so we let it go.

Let's see, it already has a set of Thorley headers, but duals instead of a single 3". The exhaust is practically new so I'm leaving it alone for now.

A thorough suspension refresh is on the list. A few bushings are new, most have 75k miles on them. It needs shocks, the typical steering box adjustment, will probably just redo the entire front end then get it aligned. I also found a sway bar for it to eliminate some of the sway I felt on the first few drives.

The Clipper is all fiberglass over a wood frame. They don't leak nearly as bad as most 70's aluminum/wood models. I looked at a few, all were total rebuilds. We also wanted something small like this one and loved the looks and fan base the Clippers have so we went for it.

As for % goal I would love to hit 20% once we do the 4-speed transmission. So that would put it right at 9 MPG. Since we'll probably only use it a couple thousand miles a year it doesn't make sense to throw $10k at it, but we'll see how much use it gets and adjust.

Glad to read what you've wrote.

The dual exhaust will need a crossover. X-style. FYI: Press bends in a system reduce reduce TOTAL system to the worst interior diameter. This will matter when engine is under load. Heat will build in engine compartment. Answer is not larger diameter pipe, but mandrel bends. David Vizard is the expert, here.

Take it to Hendersons. Have them road test and write you an estimate. Their parts are outstanding (Super Steer). Do those installs as you will if DIY is contemplated.

Front and rear antisway bars must work together as to sizing. Get their rear axle Panhard Rod. I'd also go with every single front end part they have.

[autoarcheologist]

Originally Posted by slowmover

The 440-3 was produced by Chrysler Marine & Industrial. Far better than the competition as it is built to a far higher standard. It has a number of unique parts which do not interchange with standard 440s (mainly to do with engine front drive accessories). Best to do a compression test. Champion plugs

The drivetrain is set up to run the engine at just below peak torque at highway cruise. 27-2800-rpm as I recall. It'll do this for a few hundred thousand miles

I'd love to have one again

Be sure to keep the Thermoquad. Rebuild isn't difficult (leave choke strings alone), and it'll help. Except a hard to adapt GM QJet no other carb will give better performance or FE. As above, a TBI unit will help FE, but not deliver the same power at WOT. We used to add A on electric fuel pump near tank, upstream of mech pump to avoid heat soak.

I'd use Rotella T6 5W-40 oil and Baldwin oil filter. Look into the issue of adding zinc to preserve cam lobes.

I haven't had a chance to run a compression check, but it runs great. It currently has nearly new Autolite plugs, I checked one and they look like they had just been changed. The original owner was very fastidious about maintenance. One of the last notes I read from about 1995 said it was burning about a quart of oil every 600 miles, which is good info to know.

Thanks for the info on the 440-3, it's been fun learning about it. I need to get a tach installed so I can see where it's running on the freeway, especially as we just installed new tires which were a slightly larger size (had to ditch the 16.5" wheels and finally found a set of 16" wheels with 225/75/16 tires).

I plan to keep the TQ for the foreseeable future. It sounds like the right carb for the job. I have considered adding an electric pump to make it start faster, as it is it takes a lot of pumping and cranking to start it since it sits so long between starts. A TBI swap would be fun someday, but is a much lower priority.

As for oil I was planning on changing it once with a 20W/50 then changing again with a synthetic, Mobil 1, Castrol or the Rotella. I know Mobil 1 has lots of Zinc already but a can of additive isn't a bad idea.

[autoarcheologist]

Originally Posted by slowmover

Glad to read what you've wrote.

The dual exhaust will need a crossover. X-style. FYI: Press bends in a system reduce reduce TOTAL system to the worst interior diameter. This will matter when engine is under load. Heat will build in engine compartment. Answer is not larger diameter pipe, but mandrel bends. David Vizard is the expert, here.

Take it to Hendersons. Have them road test and write you an estimate. Their parts are outstanding (Super Steer). Do those installs as you will if DIY is contemplated.

Front and rear antisway bars must work together as to sizing. Get their rear axle Panhard Rod. I'd also go with every single front end part they have.

I'll do some more research on how I could improve the exhaust once I get through more pressing issues. Unless I'm struggling for power then it will probably get bumped up the priority list.

Hendersons is a good 2.5-3 hours from here, but if we plan to be down there I will certainly have them give it a look. I will also look through their catalog and see what they have for the old Dodge's.

Thanks!

[slowmover]

Autolites for Fords. Dodge runs best on Champion. See PM sent.

The Rotella is diesel spec. A better choice as also gas compatible.

Choke should engage with following method: Slowly push throttle to floor. Pause. Even more slowly, let off to zero. Repeat once. (Or twice if testing finds it effective). To start, hold throttle open one-third. Allow high idle to run 1-2 minutes. Do not rev or change throttle position.

If it will not start with this method then something is off.

[slowmover]

IMO, if Hendersons were six hours away from me I'd be grateful. I'm going to guess I know a bit more than you. Weigh that in consideration of time and money wasted versus expert opinion the first time. Your vehicle, so do as you will. But, it's frustrating to drag things out. Or learn on the road very far from home about problems that were more cheaply and effectively fixed early on. Not much scares me about running the country in a big truck. Even an old one. But only after an expert had been thru the front end.