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Motorhome 440 Build

Laner55

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New Philadelphia, OH
I was just wanting some member input on a motorhome 440 that I recently purchased.

I pulled the 440 out of a 1973 Southwind motorhome and also got the matching 727. The motor will be going in a 1966 Plymouth Belvedere II.

I plan to use Edelbrock RPM heads. Even though they will be the most costly part of my build, it is a great head and I have heard nothing but incredible things about them. I will also be running an Edelbrock Air Gap intake. I will be topping it off with a 750 cfm Holley.

The one thing I have read is that the pistons on this 440's sit a little in the bore and do not come flush to TDC with the block, leaving me with around a 7.5:1 compression which is bad. Changing out pistons will undoubtedly solve this problem. I plan on using a Comp Cams Extreme Energy XE268H Hydraulic Flat Tappet cam. The specs on the cam are not insanely high on lift or duration, but will bring the 440 around a little more and flow way better. I will be staying with the stamped steel rockers as the cam will not see revs much past 6,000 at all.

My target for this build will be a wide power band with TQ around 475 and HP around 450. Let me know your opinions or any advice will also help. I'm all ears.
 
Not sure the matching 727 will do you much good. Being a truck transmission with a short tail shaft and e brake. With the proper parts that can be corrected. The next would be the 440 being a 73 motor home check the casting date on the block before come to any conclusions as to compression. The Southwind was a class A unit built in 73 the engine could be any year before 73.
 
I was just wanting some member input on a motorhome 440 that I recently purchased.

I pulled the 440 out of a 1973 Southwind motorhome and also got the matching 727. The motor will be going in a 1966 Plymouth Belvedere II.

I plan to use Edelbrock RPM heads. Even though they will be the most costly part of my build, it is a great head and I have heard nothing but incredible things about them. I will also be running an Edelbrock Air Gap intake. I will be topping it off with a 750 cfm Holley.

The one thing I have read is that the pistons on this 440's sit a little in the bore and do not come flush to TDC with the block, leaving me with around a 7.5:1 compression which is bad. Changing out pistons will undoubtedly solve this problem. I plan on using a Comp Cams Extreme Energy XE268H Hydraulic Flat Tappet cam. The specs on the cam are not insanely high on lift or duration, but will bring the 440 around a little more and flow way better. I will be staying with the stamped steel rockers as the cam will not see revs much past 6,000 at all.

My target for this build will be a wide power band with TQ around 475 and HP around 450. Let me know your opinions or any advice will also help. I'm all ears.
I was just wanting some member input on a motorhome 440 that I recently purchased.

I pulled the 440 out of a 1973 Southwind motorhome and also got the matching 727. The motor will be going in a 1966 Plymouth Belvedere II.

I plan to use Edelbrock RPM heads. Even though they will be the most costly part of my build, it is a great head and I have heard nothing but incredible things about them. I will also be running an Edelbrock Air Gap intake. I will be topping it off with a 750 cfm Holley.

The one thing I have read is that the pistons on this 440's sit a little in the bore and do not come flush to TDC with the block, leaving me with around a 7.5:1 compression which is bad. Changing out pistons will undoubtedly solve this problem. I plan on using a Comp Cams Extreme Energy XE268H Hydraulic Flat Tappet cam. The specs on the cam are not insanely high on lift or duration, but will bring the 440 around a little more and flow way better. I will be staying with the stamped steel rockers as the cam will not see revs much past 6,000 at all.

My target for this build will be a wide power band with TQ around 475 and HP around 450. Let me know your opinions or any advice will also help. I'm all ears.
I put a motorhome 440 in my charger. you may need different front pulleys and motor mounts. I did put in new pistons and all the bearings and new torque converter.
 
You will need to determine the compression ratio first. Most likely flat top pistons sitting way below deck. You're cam selection will depend on compression ratio, torque converter stall, and rear end gear ratio. Remember, it all works together as a system. I recently built a 440 HP spec engine very close to the performance numbers you listed. In order to get to that performance level you're going to need a compression ratio around 10:1 IMO 440'
 
Find the true cc's for your heads
pistons and compression will depend on quench and dish or FT or Dome and gasket
First determie the rpm range you want, rear gear, tire size, usage long freeway trips or cruze night be honest and realistic
no way can you pick a cam yet and BTW 268 comp is a noisey piece of crap made for a chevy
anyway you have to work out the combination of your cam duration setting the Dynamic Compression then work out the mechanical compression (head cc and piston) to get the mechanical compression
you can somewhat screw with the LCA if your compression is High widen the LCA and low squeez it together but best to get close in the first place
Do not get all your parts bought and then pick the cam- you have put yourself in a box
If your mechanical compression is to high you have to do something about it
and if it's to low you have given up torque and mileage forever
 
I went through this a year plus ago. 76 motor home engine pistons .0120 measured off the deck.
low mile near 40 k engine looked great inside. I pulled a main and rod and put it back together. swapped pans and new rear main seal.
Small comp cam and lifters , lapped the valves in , added crane springs, eddy preformer intake and 750 carb and headers.
I love it so far, It will smoke the tires and run 120 if needed plus I can by cheap 87 octane regular to feed it.
Some of the parts I robbed off my tired 383 , water pump and housing , pulleys, carb , pertronix, headers , fuel pump , oil pan.
Its a fun project.
 
Could use a edelbrock rpm 75cc head with a thinner head gaskets and increase the compression 3/4 of a point if you keep with the low compression pistons. Your goals are reasonable enough to get there without switching pistons. The rv engines are usually in good shape if they are low miles.

We are not a fan of comps XE chevy grind either, If your sticking with low compression a cam with a narrower lsa, closing intake valve sooner, assymetric cam profile are ways to help build compression. Follow wyrmriders advice figure your combo out and then get your cam. It makes no sense to do it the other way.

RV oil pan and water pump housing may be different for your car. It's been over 30 years since I put in Rv engine in a car. But it was a fun engine for no more then it was.
 
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depends on the rv
center pan or rear sumps
on changing heads
also look at what lift
if under .500 take a good look at the differences between stock and new
some high buck cnc heads actually have less flow in this lift range
try and do pistons, head, cam together to meet YOUR goals
If you are not going to do pistons later heas are a lot of $$$ for a weight saveings and a half point comp increase
but then if your heads need seats and guides...
decisions-decisions
 
back to that xe comp line thought
they close real fast and hard and thus make a lot more noise-- a symptom
just compare with a 268 lunati voodoo
you can go to a shorter voodoo or howard and get a lot more power especially downlow
match the 255 howard -the one with a 15 in the notes column - not the street farce
255 vs 268 really boosts your dynamic compression
there are others
 
Find the true cc's for your heads
pistons and compression will depend on quench and dish or FT or Dome and gasket
First determie the rpm range you want, rear gear, tire size, usage long freeway trips or cruze night be honest and realistic
no way can you pick a cam yet and BTW 268 comp is a noisey piece of crap made for a chevy
anyway you have to work out the combination of your cam duration setting the Dynamic Compression then work out the mechanical compression (head cc and piston) to get the mechanical compression
you can somewhat screw with the LCA if your compression is High widen the LCA and low squeez it together but best to get close in the first place
Do not get all your parts bought and then pick the cam- you have put yourself in a box
If your mechanical compression is to high you have to do something about it
and if it's to low you have given up torque and mileage forever


Thanks for the input. I have been looking at a lot of the cam based upon the fact that i should determine my compression first and go from there. I have looked at Lunati, Hughes and a whole bunch of others. i just want to build it right the first time and take my time on getting to the numbers i want so the engine is healthy and can run good for years.
 
Thanks for the input. I have been looking at a lot of the cam based upon the fact that i should determine my compression first and go from there. I have looked at Lunati, Hughes and a whole bunch of others. i just want to build it right the first time and take my time on getting to the numbers i want so the engine is healthy and can run good for years.
 
way to go
I've got 40 years on a jones cam that's before Mike I think
 
My current build will be similar to what you're looking at. I went with Eddy E-Street heads with 75cc chamber. I also swapped pistons and had the block decked, and will run a final compression of about 10.1-1. same RPM intake, Holley 750, 268 cam, headers. Going in my 1970 Satellite. 727 freshened up with new stall at 2500 rpm, and a 3.55 rear gear. It's being assembled this week and should see the dyno for cam break in, testing, and a few pulls hopefully within two weeks. My original numbers I was shooting for are similar to yours, but that was before the Eddy heads and RPM intake. I'll post the results when I have them.
 
Thanks mark
post all the details
compression check
etc
always looking for good data
 
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