440 motorhome engine

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'73red-duster

'73red-duster

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My nephew just bought a '69 Roadrunner. He's wanting to build a 440 for it. I found 2 motorhome motors. Anything differant besides the oil pan?
 
Some had small spark plug heads. Something about steam holes that make the heads a little different. That's all I know.
 
I have motorhome heads on my 440 (known as 452 castings, were also used on highway patrol 440s). They do have steam holes and small spark plugs. Unless you modfiy the block, the steam holes are not functional, they bolt on with no modifications.
 
Thanks for the help. He's going to rebuild whatever engine he comes up with, so I see no reason a motorhome one won't work.
 
just opened up a 73 440 from a winny, forged steel crank, windage tray, double roller timing chain, flat top pistons way down in the hole. 376 heads, with double springs on the exhaust valves and single springs on the intake sides.
 
Many of the motorhome 440's have forged steel crankshafts. The heads are said to have more waterjacket cooling area for the motorhomes and that is why they use the small sparkplugs.
They make a great base for a stroker engine.
 
if i recall correctly the steam holes are between the middle two exhaust ports. one on each side of a head bolt hole. take the head gasket and mark them on the block and drill them out if there are none there.
 
striped the bottom end completely apart today. 6pac rods found along with provisions for a pilot bearing in the crank, the slugs on the other hand...wayyyyy down in the holes... while pulling the heads off, also noted the 2 holes on both sides of each plug into the water jacket and a couple extra holes drilled into the deck and heads for coolant passage..also have never seen this yet but dampened springs on the exhaust valves and single on the intakes... probably emphasizes exhaust flow but I didn't think that there would be enough lift or usable rpm's with that cam in there to warrant the dampeners???
 
the additional holes around the plugs are to help cool the plug and reduce detonation. I have a 78 mh 440 in my 66 coronet. I have the cast crank, 452 head version. I added a "hemi grind" hyd cam, performer intake and 750 eddy carb, shorty headers. Runs decent for a mild set up. Still need some gears.
 
The water pump housing may have the inlet on the wrong side, but this is easy to fix by swapping out the correct sided housing. Go for it!

Maybe fix the low compression pistons along the way too!
 
I put a 76 440 into a 66 Coronet a few years ago, I guess it was similar to a motor home 440, low compresion and cast crank and all. I topped it with a weiand dual plane intale, 750 holley, and a Comp Extreme 268 cam. Headers and duals through 3.23 gears. It was a blast to drive. Lots of low end, ran on crap gas. Ran 13.50's all day long! I shoulda kept it!
 
IIRC 74 and older mohome 440's should have forged cranks and 6pk rods. Think any thing much newer will have cast parts. I am not 100% on that though. My 74 out of a mohome came with a 4 bbl TQ set up on it.
 
73 mh 44 I just pulled apart.. on the left is a b engine rod but same beam size roughly as an le rod, on the right is a 6pac rod, however the external balancer is a zero balance nothing special about it
 

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My understanding is, all the cast 440 cranks were external balanced, because the throws were heavier/cast. "Maybe" the exhaust valves have positive rotators ? 360 motorhomes did. Good Luck, ateam.
 
I just ran a 12.98 with my 73 motorhome 440 in a Dart. As said above, forged crank, six pac rods, windage tray. I don't know if all 213 heads are the same, but all of the exhaust manifold holes on mine go into the water jackets. Not just the two on the ends like 906 heads. Had a bit of a water leak when we first fired it up. Higher comp pistons and a good cam did the trick for me.
 
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