It has been so long since this motor was stock, I have no idea what it would be like. Funny story. When my dad first got this coach from my grandfather when he passed away, he had the heads rebuilt and installed a Crane "RV" cam. It says RV, right? So it should be for low end torque, right? Good lord no.... When I got the coach it would cackle and sound like a top fuel dragster at idle. Probably less power than stock below 3k, and when you had your foot in it the thing became insane at 4k. The sound she made was unreal, and slightly orgasmic. That big block idle loping..... I could just sit and listen to it.
When I finally had enough and pulled the cam and installed a proper low RPM torque producing cam it lost all it's audible character, but boy did it wake up below 3k. The power really starts to come on at 1500 and pulls really well to 4k. The package along with the headers/exhaust, intake, FI system, and ignition work really woke up the motor down low. And, it still has the original low compression pistons in the holes.
If you have a coach with a 440, and you plan on keeping it and using it for some years, I highly suggest you make a couple very impressive mods. Yes, one of them is some $$, but worth every penny.
1. You must get a proper cam in there. I am using a Comp cams, but Hughes also makes a cam specifically for motorhomes that on paper, looks even a tad bit better. I also advanced mine via the timing gear set another 4 degrees to bring the power down even lower.
2. With the cam change you must address the intake and exhaust side. A relatively inexpensive Edelbrock manifold and one of the current throttle body 4bbl fuel injection kits. Over a properly tuned carb, you may not see any real power gains, but your mileage will go up some, especially as you travel at different altitudes and temperatures. But the real benefit is it just works. Everywhere, any temp, any altitude, any fuel. Hit the key and she fires, idles, and runs like a much newer car. Worth every penny spent.
3. Exhaust. Right now on eBay are $99 shorty headers for 440's. Dump these into a properly sized exhaust system and let that big motor breathe properly.
I also did ignition work, but I am not sure I saw any real gains there. Swapped from mechanical fan clutch to electric and the motor seemed to rev more freely, but the real benefit was how much quieter she ran.
I am going to stop at a couple of auto parts stores after church and look for a new transmission temp gauge kit. I hate paying retail but I do not have the time now to order anything.