Those of you who have them or build them for others, how many miles have you gotten out of the builds before needing work?
I am asking because I just bought a Dodge motorhome that currently has a 318 in it. Debating on whether or not to build a stroker or a big block to replace it.

All depends how you build them. No reason a stroker engine shouldn't last 100K miles if it is built right and tuned properly and kept maintained. For a motorhome I'd go as big as you can fit in there. Not sure if a BB fits in that chassis or not but a 360 with a 4 inch crank should fit. Just be super conservative with the cam and compression ratio.

My old van had a 318 in it and I built a very nice 360 for it 35 years or so ago and towed my race car with it. I built a very nice 440 for my Dads motorhome and even ported the heads for it too. Man it ran great.

I would be tempted to look for a 5.9 magnum out of a truck, preferably one that would have been subjected to heavy loads, similar to your mh + towing. Rebuild it, transfer the whole system including fuel injection, alternater, ac, the works. I bought a core 5.9 with 200m on it and other than a lot of dirt it was in great shape! VERY little bore wear, only .0015 at the top o f the bores.
The right doner vehicle will have everything you need and would have been built to handle the load.

Do you have an example of a small block stroker going a 100k? No problem on the build as I build my own. I just cant seem to find anyone with a specific example of one with high miles.

If it were a class C I would do just that. It is a 27ft travco that weighs over 10k and will be pulling another 5 behind it. Some have also suggested a cummins but I have no interest listening to it rattle for hours on end.

Frankly, why worry about it.
As was pointed out, same rod ratio as a 454. I doubt you are going to put 200,000 miles on the thing.
If it down the road needs new rings and bearings, or even new pistons from side loading/ scuffing so what. You will have what you want until that day possibly down the road if it ever comes up.
If it does, freshen up and move on again

Because I only want to do this once. It is a pain in the [censored] getting a motor in and out of one of these. I am not a spring chicken and have a bad back that isn't getting better with age.

Because I only want to do this once. It is a pain in the [censored] getting a motor in and out of one of these. I am not a spring chicken and have a bad back that isn't getting better with age.

The only difference with a stock 318 or 360 as for as longevity compared to a stroker kit engine, would be the rod stroke ratio. All the rod stroke ratios used in the stroker kits I have used are well within the range of other stock type engines. If you buy a good quality stroker kit you will have much better components than a stock engine, I would say it would last longer. H-beams rods, forged crank and pistons, I think that is an upgrade from your stock 318.
I think the main trouble in finding testimonials for 100,000 mile LA stroker engines, is normally the type of vehicles they are built for, are driven in nice weather on weekends. So it is going to take a lot of time before they rack up that kind of mileage.
I would think the main reason for problems will be a better cooling system to get rid of the extra heat that the extra HP the engine will create. Especially in a RV application, where engines can run hot, heavy loads, in the summer, lugging up hills, etc.

Is it a class A or class B or C? How long and how heavy? What will it weigh going down the road and will you tow with it?
I think the last year Dodge put 318-3 motors in motorhome chassis was 1970, is yours one of those?
I know several SO CA drag racers that had mid 1970s class B and C motorhomes with both 440 and 360 in them and they both like the 360 motors better

This is independent of a stroker, but gas powered towing can be hard on exhaust valves.

I had a 1980 DRW Crew Cab D3500 with a 360 that I towed with for quite a few years.

Long before 100,000 miles it ate the exhaust valves up and they had to be replaced. I know the stock valves had rotators and I think they were sodium filled so don't skimp on that area.

I know it did not run too lean as it had a Air Fuel Ratio Gauge on it.

It certainly was not being lugged as it had a 4.10 rear gear and no overdrive.

I have towed with Cummins diesels ever since.

OFF TOPIC:
You know that old mechanics tale that most folks including myself thought was BS, the one about sometimes having to ring an engine after a valve job?

After I had the head totally rebuilt on this engine it would not start, it would if you squirted some oil in the cylinders but it would not start on its own.

I had to do a in chassis ring job to get it running again!

It did not run well before the heads were fixed but it would start every time.

This is a class A 27ft RV. About 10,000 lbs before putting stuff in it. I will be towing another 4k or so behind it for most of the miles I put on it. I would agree with the small block in a class C. A 440 in a van chassis would be a nightmare to work on.

Valve job is just a patch. Like you said, it can make things worse. I have done them and the car run fine for quite some time, but like you I had one that ran like chit after used more oil and was misfiring after. I guess it all depends on if there is enough left in the rings to handle it or not.

As far as the ex valves go, temps can be brought way down with a quench chamber, cam timing, and headers. My motor will get at least good stainless valves. I know the old 413-3 engines had sodium filled exhaust valves, but was not aware of any other mopar engines that did. I have considered using those heads on an RV 440 block.

That Dodge Motorhome posted in here is nice, does anyone know what the model or year is?

To answer the OP:

Turbocharger.

I know the turbo idea could be made to work, but it would wind up costing me at least an extra 3k. I know next to nothing about tuning one. Could spend 2k on the sniper setup to do it plus all the plumbing to make it work. Need to keep things simple and trouble free. Me experimenting with a turbo doesn't fit that bill. Not sure what RV you are talking about. Got a link?

Mopar made 318-3 and i believe 360-3 H.D. truck and industrial motors later for trucks and probably class A motor home chassis also.
Which motor is in yours?
I had a I.H. 24 ft. class A chassis Ute liner 13,500 Lb. GVW chassis (it looked like a early Winnie Class A) that had a I.H. 392 C.I. light duty truck motor in it that was converted to propane only. It flat sucked on power on propane so I switched it back to gasoline and ended up putting a 2 speed truck rear end it that had 6.17 low gear and 4.55 in direct. The original rear end had 4.89 in it and that rear swap was a good thing to do. Put it in low in town and use it as needed on the highways and climbing hills
That motor home weighed right at 11,500 full of fuel (120 gallons) and 100 gallons of fresh water with nothing in the grey or black water tanks, it like to cruise between 55 to close to 63 MPH due to the big over hang from the bed above the driver seat and listening to the motor beside you humming along. If I pushed up to over 65 MPH it didn't like that at all. My wide would drive it between 55 and 58 MPH and get around 8.5 MPG, I would drive it between 60 and 63 MPH and get 5.5 MPG

3rd post down in this thread.

I had the idea to use a draw-through turbo setup from a 301 pontiac on one of my beater 318's. Pretty simple setup and they come up on Craigslist from time to time for around $250.00. Something to think about anyway, you'd easily out-do a stroker across the whole torque range.

I think that is a Travco L'Espirit.

rv

Id consider a 360 core block due to the fact stoker piston offerings for the 318 are slim these days and costly. Also im not sure id use a 2618 alloy which some of the current 318 stroker pistons are, in a high mile build, Ive one with icon 2618 forged at .005 cold and it rattles cold, rattles hot, ect.

360 stroker pistons/rings can be had for about 1/2 of the 318s cost.

Id shoot for 20 more inches and reduced cost.

Good luck.

It is, thanks!

If a 440 physically will fit in you chassis, I'd suggest a V10 as one more option. Factory fuel injection, lots of torque, overdrive transmission and all the factory reliability you would want in an RV.

This may be obvious, but not touched directly on so far, the 360 is the better choice for a stroker in your application, then any bored stroked 318/340 combination, with the 360 beefier crank.

Yes sir it will be a stroked 360 magnum.

Grizzly, your mention of the v10 reminded me-they have a 3.88 stroke from the factory. Makes me feel better about the stroker.

Others have questioned this as well citing rod/stroke ratio and short piston skirts as causes, but really, it's not an issue. Plenty of OEM engines out there with what would be considered worse specs by those ill informed that last a long time.