converting from a 318/904 to a 340/727- need a driveshaft- have questions...

[ClarkWGrizwald]

I am trying to get my parts in order and i did search and i cant seem to find what i am looking for as the search function on this site isnt the best i have seen.  Anyway:

I know the driveshaft will need to be about 3" shorter for this swap- correct?
Where would you suggest I source one from? Looking for a reasonable price and it will only see 400 hp so it doesn't have to be sfi etc.
If i was to buy a used one lets say, are there any markings or identity on them to make sure i am getting the right one for my application? If I buy one out of a, lets say, 70 cuda that had a 340 and 727, will the u joint match my stock 8.75 rear end or did the 904 cars have a different yolk in the rear vs 727 cars? 

My car is a 74 barracuda

Anyone have a driveshaft that will work for me for sale?

I will have to get the kick down questions answered in a different post. Pretty sure I am going to need some changes there too.

Thanks!!!

[Burdar]

You can have your original shaft shortened.  Look for a driveline shop near you that does this.  Before you remove your existing shaft, measure how far the slip yoke sticks out of the trans.(with the car sitting on the suspension)  Once the new engine/trans is installed, you can put the slip yoke at the same measurement.  Then measure center of U-joint to center of U-joint for your new driveshaft length.

[blown motor]

Why switch to a 727 if you already have the 904? I had a shift kit put in my 904 and it performs awesome. I have a warmed up 340 in front of it.

[Chryco Psycho]

It is approx 4 " shorter , you could have yours cut down you would only need a different slip yolk that way

[ClarkWGrizwald]

I was hoping to keep the original in case i (or a future owner) ever put the car back to stock. The engine and trans are going on the shelf and taking a nap til then.

But I will get it up on the lift and take those measurements anyway since Ill need that info for the next driveshaft.

[ClarkWGrizwald]

Well, I got a good deal on a fresh 727 and converter. The 904 would need a refresh and a converter and I hear they are weaker than the 727 so.... I decided this would be the way to go. I didnt think getting a driveshaft would be a big deal but I am finding out, even the seemingly simple stuff is not so easy to find. Having owned and raced many mustangs, i am spoiled by the prevalence and low price new parts and easy to find used stuff in the market. Mopar, not so much!

You have any links to your engine build??
THANKS!!

[tparker]

I did the same years ago. I ended up taking mine to a shop and had it shortened. I was a kid with no money so it didn't cost a whole lot. Probably a $100 or so. Probably have to double or triple that now.

[blown motor]

No link to the engine build. Bored 60 over, 10.5:1, x heads, 650 Eddy carb, Lunati cam, TTI headers.

[7212Mopar]

You likely have 7260 u joints at the slip yoke and pinion yoke. 727 output shaft is bigger than 904. Assume if you go 7290 at the output shaft, you might need a conversion joint at the back.