I have 440 Motor Home Engine questions.

[Sahara]

So I have a nice, running 1976 Motor Home 440. I'm putting this in a 1970 Coronet, 727 automatic, 3.23 sure grip. I live in the arctic, so I can't just bop down to my local machine shop. They are 700 miles away.
I'm not looking for the worlds fastest car. A mild 440 is perfectly adequate for my needs so I'm trying to do bolt on mods.
I have a Sig Erson magnum grind cam. I don't have an intake yet but it'll be dual plane with FItech injection or similar. I have headers, there will be dual exhaust.
My question is heads. I understand these engines were low compression with poor heads. Is there a stock iron head that I can put on for a worthwhile gain? I'm hoping to not have to swap pistons because of the machine shop thing, and I'd don't think my low compression pistons justify aluminum heads.
Or am I wrong and need to go to different pistons? I will if I have to, I'm just hoping to not have to.

 

[BeepBeepRR]

Im working on pretty much the same 440. Check my thread here.. lots of people helping me out .. http://www.forbbodiesonly.com/mopar...p-a-low-mile-440-today.143842/#post-910849281

 

[SublimeSixpack]

915 heads off a 1967 440 HP would raise your static compression some.

 

[SimDog]

Check out this episode of Road Kill. They put on a set of Edelbrock alum heads, cam, intake and headers and went from the stock RV 440 horse power of ~200 to 350 without a piston change. They estimated a compression ratio of 8:1. Horsepower doesn't all come from increased compression ratio. A big part of it comes from the top end. You've got to get more air and fuel in and out those big blocks to get more horses out of them.

 

[IQ52]

The aftermarket cylinder heads would be worth the money, even on a low compresson engine. Here are dyno tests on a low compression 440, changing only bolt on's during one days testing. The Sig Erson would be preferable to the 509 cam we used.

http://www.forabodiesonly.com/mopar/threads/dyno-testing-a-stock-1972-440.249866/

 

[Bill Monk]

The aftermarket cylinder heads would be worth the money, even on a low compresson engine. Here are dyno tests on a low compression 440, changing only bolt on's during one days testing. The Sig Erson would be preferable to the 509 cam we used.

http://www.forabodiesonly.com/mopar/threads/dyno-testing-a-stock-1972-440.249866/

awesome thread!

 

[Sahara]

This is all fantastic help, and responses like this are why this is my favorite site. It looks like I may look into swapping pistons. I was hoping to just swap heads and perhaps get 9:1 at least.
I'm still open to advice. I'm a painter, not a mechanic.

 

[wyrmrider]

The heads you have have hardened ex seats if they have not several valve jobs and gone through the hardening
The 915 heads will need seats, guides valves and springs or you could swap in your excellent motor home valves- none finer (unless mechanical cam and racing) they flow about the same as yours ported or stock
you could freshen up your heads (new viton seals and springs- no 40 year old springs, maybe guides- your valves should be fine- they are hard chrome stems) and just change pistons to the KB with the reverse deflector- if you are interested I'll get you the number- I helped design that piston
gives you some more compression and some quench- combination of less overlap and quench can cut your exhaust gas temp big time-( ever felt the heat in a 76 motorhome or even worse with a 440Cordoba with the Magnum cam and HO converter?
you'll have to do some math and fudge head gasket thickness to make it come out right
Cam- forget the Erson chevy cam copy
what rpm range???
and get a cam ground for a .904 lifter
for street with stock converter and gears and 9:1 or lower I start a 256 @006 with .305 lift at the cam (basically stock 440 duration with more than Magnum lift) any more than that you start the more compression, lower gears, looser converter, better gas requied cycle
run LA-AMC lifters and oil through the puschrods to keep your rocker balls happy- weakness of stock rockers is pushing the pushrod through the cup and the HD rockers are long gone
roller rockers opens up a can of worms with the geometry which most do not address and wear out theri valve stems and guides (you have to space up the fulcrums and run longer pushrods)

 

[Garys1969RR]

No matter what your C/Ratio is, better flowing heads =increased torque and horsepower. Determine what C/Ratio you want to shoot for, most street motors go 9 or 10 to 1. Then look at a C Ratio calculator online, plug in all your numbers, hit the button and you will know what you're getting. Then you can juggle piston top volumes, distance below deck, head CC, gasket thickness and come up with what suits your needs. Not difficult, but requires some measuring and research.

 

[wyrmrider]

right- measure twice- cut once
as stated many times if the Iron heads take a lot of work AL may be worth looking at- just that you have to go through them out of the box also and the cr need to be bumped for the same result

 

[wyrmrider]

looking back at your first post
"Is there a stock iron head that I can put on for a worthwhile gain?"
you have an 8:1 motor, small chamber iron or AL heads may get you 8.5:1 but with the piston that far down in the hole (no quench and the plug low on one side) you are in either a no win situation or a make the best of what you have situation
What's your cranking compression and I'll take my best shot given the distance to the machine shop- you can check your motorhome motor without putting it into a car- also how many miles and do you know if it was burning any oil? if it was it was most likely just valve stem seal which you can change without pulling the heads, (and change your springs.
DO NOT USE A MAGNUM CAM WITH THAT LOW COMPRESSION (unless you are racing with lower gears)
YOu are shooting for getting the intake valve closed earlier than stock (to help dynamic compression) and less overlap than stock and more lift where the head is actually flowing air
Here's what happens with a Magnum duration (say 268 or 212-214 @.050) Things a dog with 3.23 gears so you give it more gas which makes more heat so it pings so you retard the spark which means you have to give it more gas which makes more heat...

 

[IQ52]

Heck with it. Come up with $10,000 and these guys can design a real engine for you. Or use what you have.

 

[wyrmrider]

not a 10K problem
without changing pistons
determine if a valve job is needed
if so determine how the seats and guides are
if ok just do the vj and mill the heads to almost max, blend the bowls yourself (problem here is there anyone to assemble the head where he is- would be worth it to get a spring compressor)
run the short high lift cam
In AK keep the cast Iron manifold and QJ (and heat in manifold and air cleaner stove- there is no better carb for what he's doing
or go EFI
any of you cold weather guys, snowplow
Euro Spec 0w-40 oil Mobil 1, Penzoil Platinum (sometimes less than $25 for 5 quarts at Wallmart) otherwise can be pricey- but worth it)
check and see if it's made from Natural gas not dino
The only better ATF than Mopar IV semi synthetic for cold weather is CITGO Quatrosyn (shown for Allison but works for everything but Type F) better low temp flow than even Dex VI- better high temp than anything else
long extended change specs