View Full Version : Engine and transmission questions

08-14-2016, 06:35 PM
Sorry I am new to this all.

1. I am looking at building a 440 or 383 motor. Does the donor engine year matter with in reason of course. I have a lead on 69 model year blocks in both sizes. There are many more available in the 1975 range.

2. I am also looking for a 727 tranny. Does the year matter for pairing with the 440 or 383 ? It will be going into a 1969 vehicle.

3. If I go to higher HP (400-450) in a big block from the stock 318 motor do I need to change out the rear end or can I just do a gear swap to a 3.23 or 3.55. I believe they are 8 3/4 rear ends in all of the v8 models but could be mistaken.


08-14-2016, 07:56 PM
Welcome Tyson..

1) No.. the year doesn't matter as far as fitment into your car. You could put a 440 in from a 1977 police interceptor, and it will bolt right in. The big differences between the years is the crankshafts in them. Earlier ones came with forged steel crankshafts, later ones came with cast cranks. The easy way to tell is look at the harmonic balancer. Steel crank will be less than 1" wide, cast ones almost twice that. Steel is preferable for performance use. Oh yea, forgot, other big difference is price. 66-72 blocks tend to have higher price tags because of the date codes, whereas the later years will always be cheaper.

2) Yes, this does matter. Earlier 727's (1964 and back) had a ball and trunion style connection to the driveshaft, later years had a slip yoke. You want a slip yoke style.

3) It depends on the rear in the car now. It "should" have come with a 8.75 housing under it. (I say should because over the years it may have gotten swapped out for the smaller one). If it does, then yes, all you have to do is drop out the center section and replace it with one with a different ratio. Before you do that, check to see what ratio you have, because as above, it may have gotten swapped out over the years.

You mention 440 and 383 blocks.. don't rule out the 400 as well. It's got the largest bore of any big block, and they are pretty plentiful.

08-14-2016, 09:03 PM
I'm not sure what your HP goal is but I'll add that cast cranks are said to be good to 500hp. So don't let a cast crank scare you away from buying a motor. As mike said don't rule out the 400 they take mods just as any other motor will. I have one in my dart that runs pretty good.

if you are not sure about the rear an 8.75 will not have a cover/bolts on the back of it.

08-15-2016, 08:52 AM
Checked my axle last night looks like it has the back plate on " bolts from the rear" Im assuming it is the 8 1/4 . I have read that they are able to handle up to 500 crank HP which is more than I plan on striving for. Has anyone had any experience with running one with a BB engine ?

08-15-2016, 09:27 PM
Is the pumpkin cover circular or is it all funky looking? (Just want to make sure someone didn't sneak a Dana in there)...

08-15-2016, 09:53 PM
Will an 8 1/4 or 9 1/4 even fit in a 69 B body?

08-16-2016, 08:59 AM
Will an 8 1/4 or 9 1/4 even fit in a 69 B body?

Yup.. apparently first year for them was 69....

08-20-2016, 09:58 AM
Maybe this chart will help you id your rear differential.


http://i146.photobucket.com/albums/r248/thebankerstoy/Mopar%20Factory%20Service%20Manuals%20and%20Parts% 20Books/Moparaxleassemblies.jpg~original (http://s146.photobucket.com/user/thebankerstoy/media/Mopar%20Factory%20Service%20Manuals%20and%20Parts% 20Books/Moparaxleassemblies.jpg.html)

08-20-2016, 11:51 AM

08-20-2016, 05:16 PM

08-20-2016, 09:38 PM

When I checked it earlier, there was no chart..

08-21-2016, 02:31 PM
That's the chart I used to question not only if they were available, but whether they would fit. 71 and up B-body is wider.'

08-21-2016, 04:57 PM


08-21-2016, 08:50 PM
Too much reading for my simple mind.

08-21-2016, 09:21 PM
Since you like pictures..