440 rebuild questions

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Budgetmoparman

Budgetmoparman

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I have a 75 440 out of a motor home. I am doing a cheap rebuild but have a couple questions. The motor has low miles, everything inside looks really good except #8 cylinder was seized from sitting for a long time. My plans are to hone the cylinders, get new rings, bearings, cam, and gasket set. I would like to get as much low end torque as possible because it is going in my wood hauling truck. The heads are 452 castings. First question, should I do a mild porting on the heads or is it a waste of time? Second question, what cam should I go with? The truck is a 1977 D250 4x4, 727 tranny, 3.55 gears. I know it isn't going to be a huge gain in torque by just doing this rebuild but I would like to get whatever I can out of it.
 
It hard to gain low rpm torque since all the things needed to be done are built in Stock.
You can extend the powerband (hp) decently with little to any sacrifice to bottom end and even gain some.

I'd do a little bowl work to the heads don't need to go crazy a few extra cfm will pickup some extra hp and torque. Along with a mild cam and decent exhaust and a bump in CR.
 
For your truck application you could do just whatever minimum you need to do to get it running again.
Timing gear set, bearings, cast rings and at least check the valve job by
seeing if combustion chambers will hold fuel.
Cam should be fine to use if in good shape.
Unshrouding the valves and gasket matching has always been worth the effort for me even on stock freshen up type rebuilds.
 
............I would get some .060 rod bearings and have the crank offset ground...it will gain u 13 cubes and over 1 full point of compression..............kim............
 
The best truck engine I ever had, for hauling wood, was a bone stock 440 out of a '73 Chyrsler New Yorker.

The motorhome engine, as it was built from the factory, would be a perfect application for a wood hauler. Doing a little head work (as 273 said) while rebuilding the engine would be of benefit. If the stock cam is still good, I too would reuse it.

I hauled wood, with a 1970 3/4 ton 4x4 and a 16' trailer out of the woods and up and down mountains here in Idaho, with the '73 440 from that New Yorker.
 
The cam is in excellent condition, I will probably use it. The only reason I tore the engine down was because it was seized up. It ended up being only 1 cylinder seized, the rest of the motor looks great, no ridge in the cylinders. I can still see the cross hatch pattern in the cylinders. I will gasket match the heads and clean up the runners a little. Would it be worth the time and money to shave the block and the heads to try bumping the compression up a little? I could get thin head gaskets also. Thanks for the replies. I appreciate all the help so far.
 
Milling the block and heads to raise the compression sounds simple enough.........until you start to figure what actually has to be done to get everything to bolt back up correctly.

If your engine now has 90cc heads, -.120" deck (it's probably more than that) and a .020" thick gasket you would have about 8.25:1 compression. Reduce the head cc's to 80 and you have 8.9:1 compression. But, you have to mill the combustion chamber surface of the heads .042", the intake surface of the heads .052" and done correctly the top rails of the block (where the six 1/4" bolts hold the valley pan to the block) should be milled .071".

Mill the heads those .042" and the block .020" you'll have 9.25:1 compression but you have to mill the head's intake surface .076" and the block rails .105".

All the milling may mean your pushrods are now too long and you'll have to buy new pushrods.

Maybe better to leave the compression alone. If you want to increase the compression it's probably better to buy proper pistons and have the block bored to size. You may have to do that anyway if the bore is rusted bad enough where the piston was frozen.
 
Last edited:
IQ52 said:
Milling the block and heads to raise the compression sounds simple enough.........until you start to figure what actually has to be done to get everything to bolt back up correctly.

If your engine now has 90cc heads, -.120" deck (it's probably more than that) and a .020" thick gasket you would have about 8.25:1 compression. Reduce the head cc's to 80 and you have 8.9:1 compression. But, you have to mill the combustion chamber surface of the heads .042", the intake surface of the heads .052" and done correctly the top rails of the block (where the six 1/4" bolts hold the valley pan to the block) should be milled .071".

Mill the heads those .042" and the block .020" you'll have 9.25:1 compression but you have to mill the head's intake surface .076" and the block rails .105".

All the milling may mean your pushrods are now too long and you'll have to buy new pushrods.

Maybe better to leave the compression alone. If you want to increase the compression it's probably better to buy proper pistons and have the block bored to size. You may have to do that anyway if the bore is rusted bad enough where the piston was frozen.
Click to expand...

I don't think I will be milling anything. I guess I didn't realize I would have to mill everything so much. Probably end up just leaving it the way it is. Thanks for the info.
 
One last question, I have a new torque converter on the old 383 that was in the truck, if I get the B&M flex plate that is weighted for the 440 then can I use the converter from the 383?
 
Budgetmoparman said:
One last question, I have a new torque converter on the old 383 that was in the truck, if I get the B&M flex plate that is weighted for the 440 then can I use the converter from the 383?
Click to expand...
Probably yes, as long as it wasn't originally a cast crank 383. If the 383 engine was originally a 1971 2bbl it will have a cast crankshaft and be externally balanced. Just make sure isn't two balance weights welded to the torque converter and then go ahead and get the B&M flexplate for the cast crank 440. If there are two balance weights on the 383 torque converter you can remove them and get the B&M flexplate. Supposedly there is a difference in the cast crank 383/400 torque converter balance and the 440 cast crank balance.
 
IQ52 said:
Probably yes, as long as it wasn't originally a cast crank 383. If the 383 engine was originally a 1971 2bbl it will have a cast crankshaft and be externally balanced. Just make sure isn't two balance weights welded to the torque converter and then go ahead and get the B&M flexplate for the cast crank 440. If there are two balance weights on the 383 torque converter you can remove them and get the B&M flexplate. Supposedly there is a difference in the cast crank 383/400 torque converter balance and the 440 cast crank balance.
Click to expand...
Sounds good. I wasn't quite sure. Thanks.
 
When porting stock heads, IME the bowls are the point of best returns per amount of time spent. Get a good valve job and straight valves, blend the bowls into the valve job, smooth up the short side and call it good. Recent 452 head I flowed, done like this, 237.5cfm I/196cfm E at .450 lift, with 3/8" stem 2.14/1.81 valves. Nothing special, I don't port as a profession, just my own stuff. S/F....Ken M
 
The gasket side of the port has the least restriction of the port at least until you open up the rest of the port. Adding CC with no gain. Behind the valve then the bowl are the most restrictive part with the most gain.

Look at 318willrun's video on porting 318 heads similar can be applied to yours and even look at the sticky on porting 318 heads.
 
273 said:
The gasket side of the port has the least restriction of the port at least until you open up the rest of the port. Adding CC with no gain. Behind the valve then the bowl are the most restrictive part with the most gain.

Look at 318willrun's video on porting 318 heads similar can be applied to yours and even look at the sticky on porting 318 heads.
Click to expand...
I will check out the video and the sticky. Thanks.
 
Clean it up, do only what you need to do....dependable is what it seems you want , and reasonable power.. I would say don't cut anything, polish the crank, hone the bores, use good rings...regular items, double chain and windage tray are cheap add on's
New gaskets and enjoy!
 
you need to properly measure the bores for out of round and taper to make sure they are in spec.
 
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