Well I just bought a 74 motor home with a Chrysler 400 in it. Engine started and ran transmission is good. I was wondering what anybody knows about these? Where they any different the ones in cars or not ? Either way I don't think I got hurt paid $700 for the entire thing figure yank the engine, tyranny, and rear end. Scrap the rest get some money back for a few upgrades
74 motorhome 400
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If you are putting the 400 in a truck, it needs to be a rear sump, high mount power steering, and center dump exhaust manifolds if using stock manifolds, 4wd motor mounts if you have a 4wd truck. There are some odds and ends depending on the year and combination of your truck you will have to deal with, but you can usually buy new for that. I put a 78 400 in my 80s truck and it was an easy swap. I needed exhaust manifolds, so I bought cheap ones on eBay. The power steering bracket and a cable kickdown linkage for the transmission I bought from Bouchillon Performance. Depending on the transmission, it either has the U-joints on the output shaft or it has the slip yoke like a car does.
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I seem to recall the transmissions in the full size motorhomes are often 727 with shorter tail housings, making them somewhat more desirable for certain custom applications, such as adding an overdrive unit or secondary transfer case.
Always something different on the heavy truck engines...usually you'll find the "dash 3" label somewhere on the HD truck engines. I don't remember any "dash 3" 400 engines, so you'll probably have something like a 2 BBL type cam & car type heads with better grade valves. Just decode the engine numbers from the pad by the distributer & then look it up.
I myself have a motorhome big block. They were a popular source of 440s for many different projects. The only big difference that I've heard of is that they have a "motorhome cam" I have no idea how it differs from a regular cam but its worth researching. I haven't personally verified it or researched it, only heard a few 440 owners talk about their motorhome 440 and the motorhome cam they didn't swap out cause they're lazy and how they wish they did because their charger sounds like a winnebago now.
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Most likey not a whole lot if power in stock form, but easily upgradable, potential to make a lot of power with a stroker kit.
Are you sure it's a 400 or 440? A lot of motorhomes used industrial 413's. Cars went with the 440 rather than 413 in '65 or so but trucks and motorhomes got the 413 into the 70's and possibly early 80's. There should be a flat pad at the base of the distributor. It will tell you what you have. Keep in mind the 400 is a low deck engine and the 413 and 440 are both RB, or raised block engines. The intakes and distributors will NOT interchange.
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I was more concerned about the 3 I was pretty sure I had everything else correct. I will double check the casting # as well as check by the dizzy to make sure the engine I have. I will post them tomorrow for you guys. Either way I was thinking of taking it to the local trade school and having them rebuilt it and upgrade it. The guy that teaches the mechanics class is a mopar guy to boot.
Mojack you was correct I misread the second 9 as it was an 8 so it is the 440. I ran the fuel pump to some fresh gas in a gas can since it had been setting for a couple year unstarted, put a battery in it and primed the carb after a little bit of trying she finally started and ran and boy was it smooth. I was expecting a lifter knock or missing out on a cylinder but nope ran like it came of the line. So now to pull this monster and get it in my mud truck. I would like to find out what size cam and head it has without pulling it apart so anybody with any info would be great. I also plan on running the numbers of the everything once I get it out and can see them all.
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You can take the valve cover off and read the last three digits stamped on a runner and that is the head you have. I don't think 452's heads with hardened seats for unleaded gas were offered in 74, I think they came out later. http://www.hotrodreference.com/758/big-block-mopar-cylinder-head-casting-numbers/
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irrelevant , induction hardened seats , longevity questionable , besides , Amoco high test was always lead free . Called "white gas " worked well in colman stoves and lanterns ... no lead .... when the gas went lead free everyone with an old tractor / auto etc ran out and bought additive , I never did and still run my "leaded gas" motors on todays pump gas , without a problem . Even the 1340 ....
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