And that's not "beers on the wall"
139,189 miles on my 1982 Airstream 280 original Chevy 454 engine.
There are three reasons why my engine has lasted for 139,189 miles (and hopefully a lot more to come).
1. It has never been severely overheated. I know in the past that the temp gauge needle has been buried but not to the point of boil over.
2. The oil has been changed on the average of every 3000 miles.
3. The Chevy 454 is a great work horse engine!
Here is what I would do if my 454 took a dump...
Replace it with a diesel? NO!
I couldn't afford it and the return on investment would never pencil out. Now of course I would if I got a donation from Donald Trump and was asked to only attend his next wedding in return. And it would be a modern day diesel. But let's face it, most of us old Airstream MH owners are on a "budget", otherwise even though I love these old coaches, if I had the money, I would own a new million dollar diesel pusher, not a 30 year old Airstream.
Next, I would carry a wooden paddle with me at all times...you know, the one that our mother's paddled our butts with when we where children (and in a time when that was not considered child abuse)!
The wooden paddle would be used to hit myself in the back of the head every time the thought of "high performance" entered my little brain.
At a cruising speed of around 60mph, my 454 turns about 3000rpms. That's not going to change with the gearing of the rear end and no budget to add a Gear Vendor unit. When heading up those 8 mile long 5 percent grades going over the Siskiyou's between California and Oregon, in second gear and with the loud peddle pressed firmly to the floor, the rpm range is between 3500 and 3900. I would say that the average operating range is between 2200 and 3000rpms.
What I would want then is to build a motor with lots of torque in this operational range and with gas mileage in mind. I would also build a motor within a budget that would be reasonable for the application it was to be used in...pulling an RV down the highway. For me this means very little in the way of "high performance" parts. High performance engines are designed to run in the 6000 - 8000+ rpm range, not an RV engine by any means.
Many top engine builders such as David Vizard state that four bolt main 454 blocks are over kill for anything under 600hp and 625 pounds of torque. I spoke with Cliff Ruggles, the premier Quadrajet carb builder, on the phone one day and asked him if I should replace my stock intake manifold with an Edlebrock Performer. He said if I replaced my stock manifold, I would be wasting my money and that I would regret it in performance and gas mileage. I was going to replace my stock HEI ignition coil with an expensive high performance coil until I did the research from the manufactures and found out that the stock unit works fine up to 6000rpms and that's when the high performance units are required to maintain an adequate spark. The one aftermarket component that I do believe is well worth the expense is the Banks exhaust or a Banks type of exhaust as many other have attested to and which I have on my 454.
If my block was still usable, I would continue to use it. I would do all the work myself except of course the machining. If my block, crank and rods were not usable, I would consider a crate engine, but most are not designed for RV usage, so I would be very careful in my choice.
My 30+ year old 454 with 139,189 miles on it is still running strong! It idles smooth and I don't see smoke out the tail pipe. Yes, it burns it's requisite amount of oil, but hey its a Chevy 454 from an era long ago. But then my Polaris RZR ATV burns maybe 3 times as much oil.
Keeping all this in mind has allowed me to spend those hard earned dollars on my toy where I do usually run it with the load pedal to the floor...my RZR. There are however disadvantages of running a high performance vehicle where one likes to hear that loud exhaust such as the $2000 I just spent rebuilding the clutch, rebuilding the shocks, replacing all suspension bushings, balls joints and tie rod ends. This is a result of running that pedal to the floor. Last year I installed a header and tuner system on it and although it sounds great (and loud), I swear it has cut my gas mileage in half!
Of course, I will have to take all this back if my 454 blows on our next trip to Yosemite in October!