Upgrade M880 to Big Block

[77 M880 W200]

I'm considering an upgrade to a big block (440) and wanted to ask what changes, bell housing, torque converter, etc. would have to be done to my transmission/transfer case?

 

[Bob H]

Big block motor requires big block transmission

 

[77 M880 W200]

Bob, thanks for the reply. I've poked around the internet and have not found conclusive evidence to support a direct swap from small to big block. I talked to a reputable trans shop owner near me and his recommendation is to ensure I get the flexplate, flywheel and torque converter (for balance purposes) THEN check the web to verify his thoughts.

I did see one site that showed a different bolt spacing between the big & small block bell housings - but haven't found other sites to confirm. Do you or anyone else have a site that you can share with me?

 

[Bob H]

www.ramchargercentral.com
I believe the transmission case is different (Automatic) the manual may be just a bellhousing difference.
I'm pretty sure you would need the whole big block transmission for the swap

 

[gerrykan]

The bellhousing to engine block bolt pattern is different between big and small block Dodges, as Bob pointed out.

Somewhere in the early 1970's big blocks went from internal balance to external balance, requiring the correct flywheel or torque convertor. I cannot remember the exact year right now.

A forged crankshaft motor(internal balance) will have a thin harmonic balancer on the front, and a cast crank motor(external balance) will have thick balancer.

 

[dtracy22]

You would need a big block transmission. Bell housings are not removable. Also need truck oil pan and big block truck engine mounts and exhaust manifolds. Check out this site for conversion parts http://www.bpeusa.com/BPEtruckKit.asp
Cast crank 400's and 440's do use an external balance flywheel or torque converter, so keep that in mind.

A 360 swap is much easier.

 

[clinto]

As a 20+ year Mopar guy, ex-Mopar Nationals judge, I can unequivocally tell you small black and big block engines take their own transmissions. As the above posters stated, bellhousing pattern is totally different between small block and big block and since Mopar automatics have the bellhousing cast into the case, you will need a big block case to go behind a big block.

As the others stated, the big block manifolds for truck are center dump versus rear dump for passenger car, so you'll need them or headers. The oil pan is big block specific as well.

I have a brand new Muscle Motors 440 bracket killer engine kit if you're interested. Not cheap, but it's all the best stuff you can buy: New MP forged internal balance crank, HP rods, new Ross .030+ pistons, etc.

 

[77 M880 W200]

Bob / GerryKan / Dtracey22 / Clinto,

I really appreciate your replies and insight, to give an update of where I am. I located a 77 W300 with a 440 & Auto trans that will arrive early next week. Thankfully it will have all of the accessories so I don't have to them down! Will be pulling my SB motor & trans this weekend - then do a swapout of the trans internals ( the new trans needs rebuilt ) since my trans is in really good condition. Thanks again.

 

[dtracy22]

That W300 should have a Dana 60 front axle. I would swap it into the M880 also

 

[77 M880 W200]

The owner is keeping the rest of the truck for another project - I tried to buy the entire truck to have spares, no luck! I'm happy with what is on its way...

 

[gerrykan]

You will enjoy the extra power, especially if towing anything.

 

[77 M880 W200]

UPDATE: Motor & Trans arrived and in better condition than expected. Trans removed and dissassembled for rebuild. Radiator sent to shop for hot tank dip and flow-check-not good. Ordered HD radiator from O'Reilly (have account and they price match!).

FYI - Flowtech Ceramic headers 3500FLT are not the correct headers for a big block, like some parts retailers show in their system. The correct Flowtech Ceramic headers are part number 3504FLT. I called the manufacturer (Holley) and they verified the fit.

 

[overlordofmars]

Sounds like a neat project, I have two 440 drive lines here, might be a neat project for me to try.

 

[rebelreck]

I have a 440 and a 383 Magnum truck. They are a world of difference from a small block truck. The Green Beast runs a 383 Magnum out of a 68 Road Runner, thats been built up some. It will smoke all 4 tires!!!But that is hard on the drive line.

 

[77 M880 W200]

UPDATE: The 440 is running smooth as silk, the rebuilt trans still needs some slight adjustment on the throttle linkage to dial-in the shift patterns. Right now it (trans) is at specs - will make adjustments until I'm happy.

Decided to put ceramic coated headers - when I fired it up, sounded like a monster!

 

[dtracy22]

DO NOT use the linkage to adjust shift timing. At WOT the lever on trans needs to be at all the way back. Set it there and leave it. Its for line pressure and not shift points. Shift points are controlled by the governor springs on tailshaft.

 

[77 M880 W200]

Dtracy, thanks for the tech tip! So far the shift patterns are acceptable, a little road time has helped. The 4:10 gears don't like highway speed - that big block screams at those speeds, have decided to take the scenic routes...

 

[SGTStewart]

Pictures or I call BS on this whole thread.

 

[77 M880 W200]

Hey Sarge - you can say what you like, my smile says it all when that 440 fires up through those headers. These pics are old, need to snap some recent ones and upload.