Engine and Trans R&R

Hi all,

As you know, last year I purchased a 1976 Monaco Class C motorhome, built on a 1975 Dodge MB300. Although the 360 2bbl only had 58,000 miles, I wanted to pull the engine and freshen it up. Years ago I had a 1973 Fireball Class C built on a 1972 MB300 chassis, and the nylon timing gear gave up the ghost with little more than 52,000 miles, so I wanted to upgrade some of the components and have a reliable lump that would give us years of fun.

When I pulled the heads, my eye caught a visible casting flaw between the #5 & #7 cylinders, and I'm amazed that the head gasket never blew. At this point, I knew I was in for a rebuild. When I started doing my research, I found that buying a reman'd 360 would be cheaper than having mine machined. I bought a reman'd 360, bored .030" over, from a seller on eBay for $1595, no core charge, free shipping and a 5yr/unlimited mile warranty. The seller also let me pick my own camshaft, so I went with a Mopar Performance camshaft P4452759AE. My understanding is that this cam closely resembles the cam that was in the 340 and what Mopar used in the E58 360 police engine. I'm also swapping in a 4bbl intake and ThermoQuad carburetor. When I ran the numbers on the desktop dyno, it gives great torque through 3500RPM.

This last weekend I finally pulled the old block and dropped the A727 LoadFlite. Since I have a reman'd engine, I might as well have the tranny rebuilt, so that everything is new. I'm also going to install new motor mounts, trans mount and rubber suspension bushings while I'm in there.

Here are some pics of my work so far. If you guys have any suggestions, I'm all ears. It's been years, since I've tackled a job of this size.

Would have been a good time to add fuel injection as well. Even TBI would have been a big improvement over the carb, and multi-point isn't much more expensive..

I agree with Gary, Check out http://fitechefi.com/ I have no experience with this system but looks interesting and then there is always Holly  https://www.holley.com/products/fuel_systems/fuel_injection/

Gary RV_Wizard said:

Would have been a good time to add fuel injection as well. Even TBI would have been a big improvement over the carb, and multi-point isn't much more expensive..

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HAHAHAHAHAHAHAHAHAHA! You wanna gift me the cash for that expense? I'm just a poor, retired & crippled Soldier trying to get the best bang for my buck. I pulled the 4bbl intake and ThermoQuad from a 1983 Dodge van for $25. Rebuilding the ThermoQuad cost me $30.

I personally like carburetors, because they're easy to work on & there are no electronics to fail. My daily driver is a 1976 AMC/Jeep CJ-5, and it has the original Carter YF carburetor; I can consistently get 19MPG on the highway with it, and that's not bad for a 41 year-old 258 I-6 engine.

If I had cash to throw away, believe me I probably would go with the EFI, but that's just not a feasible idea.

Go with a quadrajet instead of the thermoquad, it will run much better. I had a 24ft Minniwinne years ago that would get over 10 mpg with a 360 running a quadrajet. I could never get the themoquad to run right. I used a later model 800 cft quadrajet off of a 454 on my 360 and it ran great. Only problem with the quadrajet many had leaking wells, but they can be repaired, pretty easy.

Charlie 5320 said:

Go with a quadrajet instead of the thermoquad, it will run much better. I had a 24ft Minniwinne years ago that would get over 10 mpg with a 360 running a quadrajet. I could never get the themoquad to run right. I used a later model 800 cft quadrajet off of a 454 on my 360 and it ran great. Only problem with the quadrajet many had leaking wells, but they can be repaired, pretty easy.

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Hey Charlie,

    I'm very familiar with both carbs and am well-versed on tuning them. I have a spare Quadrajet sitting on my parts shelf, but the ThermoQuad is just as good, in my opinion. I know a lot of guys hate them, because of the phenolic bowls, but I've never once had an issue with them. The ThermoQuad is picky in that, if you don't follow the tuning steps in order, it never runs right. This one is 800cfm and came from the same '83 318 van from which I got the 4bbl intake.
    If, for some reason, it gives me trouble, I'll throw the Quadrajet on and go from there. You couldn't pay me to put a Holley on it, though. I've never been a fan of them. The Quadrajet or ThermoQuad, once you tune them they're good to go; the Holley always seems like it needs constant tuning.
    I'll let you know how it turns out. I'm still a ways away from dropping the new engine in. I still have to power wash the engine compartment, get the ancillary engine parts hot tanked, switch to a double roller timing chain and gears (reman'd engine came with single) and a few other things. If I rush, I know I'm going to miss something, and I want to make sure I don't do that.

Looks like you're cruising along nicely. EFI would be nice but a properly tuned carb will do you well. How long did the engine sit open? Seems like a lot of cobwebs or fuzz on the pistons.

Frederic said:

Hey Charlie,

    I'm very familiar with both carbs and am well-versed on tuning them. I have a spare Quadrajet sitting on my parts shelf, but the ThermoQuad is just as good, in my opinion. I know a lot of guys hate them, because of the phenolic bowls, but I've never once had an issue with them. The ThermoQuad is picky in that, if you don't follow the tuning steps in order, it never runs right. This one is 800cfm and came from the same '83 318 van from which I got the 4bbl intake.
    If, for some reason, it gives me trouble, I'll throw the Quadrajet on and go from there. You couldn't pay me to put a Holley on it, though. I've never been a fan of them. The Quadrajet or ThermoQuad, once you tune them they're good to go; the Holley always seems like it needs constant tuning.
    I'll let you know how it turns out. I'm still a ways away from dropping the new engine in. I still have to power wash the engine compartment, get the ancillary engine parts hot tanked, switch to a double roller timing chain and gears (reman'd engine came with single) and a few other things. If I rush, I know I'm going to miss something, and I want to make sure I don't do that.

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I even installed a 2nd evaporator under one of the rear seats to cool the rig going down the road, didn't have a generator. That Chrysler compressor worked like a charm, wouldn't freeze ya out but it kept it comfortable. I always liked that 360 engine, had a few of them through the years. First one was in a 76 Cordoba, great car. I could never get my thermoquad to run right, but I was able to work on and get the quadrajet to perform. I still have a couple in my stash. Still have one on my 77 Trans Am, 59000 mile car I bought in 1980.

Raidmagic said:

Looks like you're cruising along nicely. EFI would be nice but a properly tuned carb will do you well. How long did the engine sit open? Seems like a lot of cobwebs or fuzz on the pistons.

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LOL! That would be the Cottonwood fuzz that floats around every Spring. I pulled the heads last October and, when I saw the casting flaw, decided that the block could sit in the engine bay as is. I sprayed the cylinder walls with oil, in case someone wants to buy the block and turn it into a throw away race motor.

Yeah, EFI would be nice, but I'm po! Well, not really, but I have better things on which to spend my money. I also have a 1987 S&S 10.5 Camper that I'm repairing, so it's getting my equal attention. I use it to go hunting.

Charlie 5320 said:

I even installed a 2nd evaporator under one of the rear seats to cool the rig going down the road, didn't have a generator. That Chrysler compressor worked like a charm, wouldn't freeze ya out but it kept it comfortable. I always liked that 360 engine, had a few of them through the years. First one was in a 76 Cordoba, great car. I could never get my thermoquad to run right, but I was able to work on and get the quadrajet to perform. I still have a couple in my stash. Still have one on my 77 Trans Am, 59000 mile car I bought in 1980.

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I fell in love with the Quadrajet, when I bought my father-in-law's 1979 L-82 Corvette. When my late wife and I had our second child, we realized that, as nice as the Vette was, it wasn't a family car, so we traded it for the 1973 24' Fireball Class C. Keep in mind this was before Barrett Jackson made people proud of the cars they owned; late 70's Vettes weren't worth a hoot. The Fireball was a great family memory maker, but I will tell you that I'd love to meet the knucklehead engineer who thought that putting a swamp cooler on a wood-frame RV was a good idea.

Way to go Frederic,

Don't ya just love it when you have the ba**s and expertise to R&R the engine and tranny and then every one else knows better than you how to do the job. GRIN
Obviously your not a rookie. FWIW, nice selection of components.
I got the same rhetoric when I R&Red the 460/528 stroker and tranny in my 95 Bounder.
Keep the posts and pictures coming.

Richard

Make sure you hot tank the intake manifold and heads and replace the heat riser or you are in for a world of grief with the automatic choke. That design is a pita. Oh, and carry a spare ballast resistor and ignition module, you will need them.
I wonder how well a high performance cam will work in your application. A high lift short duration would boost low end torque where you need it.

That cam isn't exactly a drag racers dream. It works from off idle to around 5000 rpm if I remember correctly. A friend ran that same cam in his old hippy van. The OP should be fine with it.

Well folks, it has been 493 days, and I'm happy to report that the engine and transmission are in and we have a heartbeat! I will say, though, it was not without its hiccups. The engine I bought turned out to be a total dud, as was the jerk who sold it on eBay. Top tip....if the engine builder has 100% positive feedback, it's because he takes two months to build and ship the engine, which just so happens to be the amount of time that's needed to pass, before you can no longer leave feedback on a seller.

The silver lining is that an engine builder, who's a drag racer, has a shop down the road from me. He has forgotten more about engines than I could ever learn. When we tore the engine down, we found out that the heads had used valves that still had carbon on them. Most of the pushrods were bent, the worst being 0.024" out of straight. The camshaft was not the one I ordered. As the engine builder put it, it was good for a '76 Dodge Dart. With the pistons and rods out of the engine, it took 24 lb/ft to turn the crank. Turns out the mains were .001" smaller than the crank and bearings.

Once my builder got everything squared away and rebuilt, we put it on his dyno and broke it in with his Edelbrock Q-Jet, which he knows provides perfect A/F ratio. After we broke the engine in, we put the Thermo-Quad on and ran three passes. His dyno adds load to the engine, so you get true RWHP; at 12? BTDC and 32? total advance, the engine produced 285HP & 325 lb/ft @3500 RPM. The engine has 9.0:1 CR and runs great on 87 Octane.

After having taken the old engine out through the passenger door, I vowed that it was not going back in the same way, so I had a machine shop engineer my cherry picker boom to put the engine back in from the front. The result was that, at 42" from the ground, the boom was parallel to the ground, which gave me just enough room to re-install the engine. It took my son and me exactly 1 hour and 17 minutes to install and bolt up the transmission and engine to the chassis.

While the engine and transmission were being rebuilt, we had the interior completely redone. Call it kismet but the gentleman who owns the local RV furniture shop here used to live in Junction City, Oregon and installed all of the interiors for Caribou Manufacturing, which made Monaco's at the time. It was cool to see his face, as if one of his kids had come home. The result is nothing short of spectacular.

So far, we have taken two day trips and have enjoyed every moment. The original single exhaust is still on, but it will be replaced next year, along with the entire suspension. I'll be upgrading to the MB400 suspension components front and rear and replacing the rubber with polyurethane. For now that's about all. The S&S camper I talked about in my earlier post was damaged during a storm on our property. As a result, I've been taking it apart, salvaging the good pieces. I transplanted the medicine cabinet to the Monaco's bathroom, installing it in the shower, as there was no place to put shampoo or soap.

Here are some pics of what I've done.

Very impressive!

Great work! It always does my heart good to see something saved from a bad demise. I pray you get many enjoyable trips and many great memories from it.