Big block vs. small block driveshaft?

[Phantom440]

Hi everybody- hope you're doing well!
I'm in the process of converting my 904 automatic to an 833 4-speed on my '72 Coronet. Right now I've got a mild 318 under the hood, with plans for a 440 later.
The 904 is out. The 318 is still under the hood. I'm planning on installing the 833, then putting an 8.75 in at the back, and having the driveshaft made, then driving it around, saving up, and doing the 440/bellhousing swap last. My question is, will the 440 swap "move" the 833 back, resulting in the need for a shortened driveshaft? Or will the transmission and driveshaft be in the same location no matter what's in front of it?

 

[rumblefish360]

No, they all bolt and mount to the same point. The transmissions tail on the 833 & 727's are longer than the 904's. A shortened driveshaft is needed.

Also, if you have/had a 8-1/4 rear and swapped in another rear end, the larger the rear, the longer the snout. (Where it bolts/connects to the driveshaft)
Here again, a shorter driveshaft is needed.

Search for Marty, supershafts here on the board, it's his biz.

 

[Phantom440]

Thank you, Rumblefish! That's what I wanted to hear! So my plan is while it's down, get the 833 in, swap in a rear, and then just have one driveshaft made once the trans and rear are both in. I'll look for Marty/Supershafts. God, I love this site. You guys rock!

 

[rumblefish360]

That's what it's all about, helping the fellow MoPar guy out.
Then on the in between we pick on each other laugh out loud

 

[PurpleBeeper]

Hmmm....I'm thinking your plan is a very good one and makes a lot of sense. If you go with a flywheel that accepts a 10-1/2" pressure plate (I think that's the 130 tooth) & your 318 is internally balanced (I'm pretty sure it is), then you wouldn't even have to change clutches. As long as you make sure you eventually put in an internally balanced 440 then you'd just have to change the bellhousing later on. Everything else....flywheel, clutch disc, pressure plate, throwout bearing...maybe even the clutch release fork too....would swap right over to the big block.

Somebody jump in here if I'm off in left field.

 

[rumblefish360]

Nope, I do believe your correct.

 

[5.7 hemi]

You'll need a different trans yoke also. The 727 and A833 use the same yoke, 904 is not compatible.

 

[Moms68]

Is Marty still on this board? Is there another driveshaft member here?