440 Motor Home Engine Build

[Millet11]

Hello all,

I am new to the forum and wanted to get some advise. I am in the process of buying a 1976 440 motorhome engine from a guy i work with for $400 for my 1972 dodge charger. I'm supposed to look at it this thursday and as long as it isn't a boat anchor i'm probably going to buy it. Odometer on the motorhome said 45000 miles when they took the engine out. I already have a Edelbrock Performer RPM Intake (Paid $50 at a swap meet) and a set of headman headers for a b body (also paid $50 at a swap meet). I have a 2k budget for the rest of the build, what do you recommend for Cam, Carb, torque converter etc. I already planned on buying a MSD Ignition kit. looking to get 350 hp and over 400lb/ft torque. My charger already has a 727 and a 8 3/4 rear end.

Thanks

 

[1969CoronetR/T]

I believe the motor home engines are lower compression.

 

[Millet11]

Yes i believe they are somewhere around 8:1 compression ratio.

 

[PurpleBeeper]

That's a tough one to stay under $2000, but it's possible. The first thing is to make sure the engine isn't seized and/or has two rusty cylinders forcing you to rebuild the engine since that will take all of your budget just to do that. If the bottom end can be used "as is", then try to increase compression ratio by using the thinnest head gaskets you can find (allowing you to keep your special heads)

FYI, motor home 440's have a special coolant loop in the cylinder head that surrounds each spark plug. Motor home blocks just have extra holes drilled into the head mounting surface (2 per cylinder) that match up with the coolant loops in the heads. You have to make sure you've got motor home head gaskets (or drill holes in std. 440 head gaskets) so you don't block those holes.

Anyway, if you can't live with the 8.5'ish compression ratio with just the thin head gasket, then forget about that special coolant look & try to find some closed chamber heads that will raise your compression ratio about a point or so. The '915 HP heads are pricey, but you can get the same results cheaper by getting some of the non-HP closed chamber heads with 2.08/1.60 valves & getting a valve job done to increase the exhaust valve throat diameter & install some common 1.74 exhaust valves from any '68+ big block (I did this myself in the past).

1737637 361 1958-59 1.94 1.60
1944705 361 1958-59 1.94 1.60
1737637 383 1960 1.94 1.60
2206324 361/383/413 1961-62 2.08 1.60
2206924 361/383/413 1961-62 2.08 1.60
2463200 361/383/413 1963 2.08 1.60
2406516 361/383/413/426 1964-67 2.08 1.60
2408520 413 1964 2.08 1.60
2402557 413 - 300J 1963 2.08 1.74
2402286 413/426 Max Wedge 1962-63 2.08 1.88
2463209 426 Max Wedge 1963 2.08 1.88
2406518 426 Max Wedge 1964 2.08 1.88
2406158 383/440 1967 2.08 1.60
2780915 383/440 1967 2.08 1.60
2780915 440HP 1967 2.08 1.74
2843906 383/440 1968-70 2.08 1.74
2951250 440 1968 2.08 1.74
3462346 383/400/440 1971-72 2.08 1.74
3462346 400/440 1973 2.08 1.74
3751213 400/440 Motor Home 1973 2.08 1.74
3769902 400/440 1974 2.08 1.74
3769975 400/440 1975 2.08 1.74
4006452 400/440 1976-78 2.08 1.74

Besides that, I'd say just stick with a hydraulic cam with not too much overlap (since that will bleed of compression) along with the appropriate HP springs (single) & lifters. I wouldn't spend the money on a stall converter if it were me, but I might look around for some 3.55 gears (or 3.91/4.10's if you don't mind driving down the highway at 4,000 rpm and gas is cheap in your area). The Themoquad you most likely have on that engine is a good carb IMO.

 

[Schober Motorsports]

I got one these kinda 440's, originally out of a 76 Winnebago... Ran it with the stock pistons for a little while, ran best of 12.96, with a tail wind! None the less, I tore that motor down this winter and those pistons were about .150 thou down in the hole. Just some room for thought, thats 7.6 -1 compression!

 

[Ghostrider 67]

Search for IQ52's thread on this subject, it will be a great primer for what your contemplating.

 

[mopar 3 B]

Pulls my 10000# class C motor home around just fine. Are these engines gutless "NO"

 

[Millet11]

That's a tough one to stay under $2000, but it's possible. The first thing is to make sure the engine isn't seized and/or has two rusty cylinders forcing you to rebuild the engine since that will take all of your budget just to do that. If the bottom end can be used "as is", then try to increase compression ratio by using the thinnest head gaskets you can find (allowing you to keep your special heads)

FYI, motor home 440's have a special coolant loop in the cylinder head that surrounds each spark plug. Motor home blocks just have extra holes drilled into the head mounting surface (2 per cylinder) that match up with the coolant loops in the heads. You have to make sure you've got motor home head gaskets (or drill holes in std. 440 head gaskets) so you don't block those holes.

Anyway, if you can't live with the 8.5'ish compression ratio with just the thin head gasket, then forget about that special coolant look & try to find some closed chamber heads that will raise your compression ratio about a point or so. The '915 HP heads are pricey, but you can get the same results cheaper by getting some of the non-HP closed chamber heads with 2.08/1.60 valves & getting a valve job done to increase the exhaust valve throat diameter & install some common 1.74 exhaust valves from any '68+ big block (I did this myself in the past).

1737637 361 1958-59 1.94 1.60
1944705 361 1958-59 1.94 1.60
1737637 383 1960 1.94 1.60
2206324 361/383/413 1961-62 2.08 1.60
2206924 361/383/413 1961-62 2.08 1.60
2463200 361/383/413 1963 2.08 1.60
2406516 361/383/413/426 1964-67 2.08 1.60
2408520 413 1964 2.08 1.60
2402557 413 - 300J 1963 2.08 1.74
2402286 413/426 Max Wedge 1962-63 2.08 1.88
2463209 426 Max Wedge 1963 2.08 1.88
2406518 426 Max Wedge 1964 2.08 1.88
2406158 383/440 1967 2.08 1.60
2780915 383/440 1967 2.08 1.60
2780915 440HP 1967 2.08 1.74
2843906 383/440 1968-70 2.08 1.74
2951250 440 1968 2.08 1.74
3462346 383/400/440 1971-72 2.08 1.74
3462346 400/440 1973 2.08 1.74
3751213 400/440 Motor Home 1973 2.08 1.74
3769902 400/440 1974 2.08 1.74
3769975 400/440 1975 2.08 1.74
4006452 400/440 1976-78 2.08 1.74

Besides that, I'd say just stick with a hydraulic cam with not too much overlap (since that will bleed of compression) along with the appropriate HP springs (single) & lifters. I wouldn't spend the money on a stall converter if it were me, but I might look around for some 3.55 gears (or 3.91/4.10's if you don't mind driving down the highway at 4,000 rpm and gas is cheap in your area). The Themoquad you most likely have on that engine is a good carb IMO.

Thank you, this information is very helpful. I don't want to mess with the bottom end of everything is all good. I have no problem running a thinner head gasket to bump compression. I've been looking at mopar performance purple hydraulic camshaft .509 lift, it comes with lifters and changing the springs on the 452 heads that I believe are on the engine. I have a bore scope so I will inspect the cylinders before I buy it. I dont believe it has a carburetor on it, going to ask around and see if I can find an 800 or 850 cfm holly or edelbrock carburetor. Also been looking around for a set of 915 heads on eBay and I'll keep an eye out at swap meets.

 

[IQ52]

If you try to use the 509 cam you will be needing some gears and a torque converter.

Here are two versions of the same low compression test using a 509 camshaft in a 440.

http://www.forbbodiesonly.com/moparforum/showthread.php?58687-Iron-head-test-starting-on-78-440

http://www.forabodiesonly.com/mopar/showthread.php?t=249866&highlight=1972+440

 

[Auggie56]

Here's my thread on the same subject. BTW, I have a 78' thermoquad if your interested PM me.

http://www.forbbodiesonly.com/moparforum/showthread.php?106488-That-440-235-HP-Motor-Home-Engine

 

[Millet11]

I brought the 440, we took the valve covers off and everything looked good, bore scoped the cylinders, everything looked good, no rust in the cylinders, cracked pistons, or noticeable ring ridges so i figured it was worth the $400 he was asking and it did have a thermoquad carb on it. I've been doing some more research on cams, Has anyone here used a Hughes Engines Whiplash Cam? http://www.hughesengines.com/Index/...arch=SMC3245BL+Whiplash+Camshaft&partid=30173

 

[moper]

I'm not a fan of Hughes stuff and idle sound is the wrong reason to buy a camshaft. But if you're going to run one, IMO, that one is too large for the true 7.xx:1 compression ratio. I'd look at the SEH2428BL-11 or smaller.