318 to 440 swap

[Rex]

Now this is just in the thought stage, I have a 72 champion 23 foot with the dodge m300 chassis. It has a 318 right now and I had taken it on a 200 mile round trip which is did flawlessly!! (Lots of brake work, 6 new tires, new front wheel bearings, ect) my only gripe is the power. Which it has none. I don't need to go 70, 55 is quite comfortable in it but any hill and I'm down to 35-45. Now for my questions, I know the trans is different between big n small block, but what's about frame mounts on these? I've swapped motors around in cars and trucks but never a motorhome chassis, and is the outlets on the radiator the same on a big block? My other thought is find a diesel

[LJ-TJ]

Well Rex I can tell you this from experience. I had a 1975 21' Winnebago Brave with the 318. I got 5 to 8 miles to the gallon. The wife on the other hand could get 8 to 10. Your right in that the 318 while it got the job done was a tad under power. If I had to go up a hill and I was going down a hill I'd speed up to make the top of the hill. If I was on the flats and getting ready to go up the hill I'd speed up. The old girl had a short in the dash wiring and burnt to the ground.
Not to be discourage we went out and bought another 1975 21 footer Winnebago Brave which had a 440. LOVE IT totally different rig. No I get the same mileage 5 to 8 with the wife bettering me but the extra power is nice. If you make the change you'll love it. I think the 440 will bolt right up to your 727 transmission. Personally after everything I've read here. The time money in a Diesel swap just won't pay off. For the work involved and the money and the gain in gas mileage your just as well off spending the money on gas. Hm? There's chaps here that should be able to tell you if it's a straight swap. I think it is.

[RedneckExpress]

Please correct me if I'm wrong, but those chassis all shared the same A727 transmission didn't they, which had bolt holes on the shroud to take either the small block or the big block?

[Elandan2]

There are two different bell housings for 727's.  Small block and big block engines are not the same.  Rick

[DaveVA78Chieftain]

Dodge used the 318 and 413 in 70/71.  Dodge put the 440 into the RM series chassis in 73.  So, hard to say for sure however from the parts book:

On the engine:
The rubber insulator blocks are the same however the bracket that attaches to the engine is different.

Transmission mount
Looks like it might be the same for a given year across all engines

Bell housing is different

[EldoradoBill]

Depending on skill and ambition you might want to consider a 90s 5.9, plenty of pickups rusting away out there so it's easier to come by in running condition, better economy,  they are higher HP rating than the low-compression 440, just make sure you get the entire harness PCM and O2 sensor from the donor vehicle.


Bill

[Rex]

i did toss around the idea of a late model 5.9, fuel injection would be a bonus. I thought about a V10 as well. Or a 5.9 cummins, that would be perfect. But that's big money there