Easy swap???....from 340 to 440 • The Dodge Challenger Message Board

by **Jon Roberts (Slickjohann)** » 14 Apr 2002 15:16

I'm looking at swapping a 440 into a 340 challenger. The only problem is the challenger is a 73 and the 440 was not availble that year. Had the car been a '71 or prior, I would have no hesitation, but are there any changes I have to make to fit the 440? Can the "k" bar in the car now support the 440? Is it the same "k" bar used on the '70 and '71 440 challengers? Also, the current tranny is a 904 auto, I want to put a 4-speed in-line in the car. Any changes or adjustments to be made there? Any suggestions on where to get a 4-speed in-line? thanx, jon

by **Johnny D (Johnnyd)** » 14 Apr 2002 15:37

The engine will bolt right up to your existing k-member. You may need to change motor mounts on the engine to the e-body big block mounts ($12.00 @ AutoZone) and you will need to have your drive shaft shortend to fit the car. Also, different torsion bars were used to compensate for the extra weight of the engine (I think about 150 lbs heavier) - which you don't necessarily HAVE to do but the car will handle better if you do. I have no suggestions on the tranny you want.

by **Tedd Lister (Teddl)** » 16 Apr 2002 1:59

The engine swap would be relatively easy but keep in mind in addition to Johnny D's points that you might need a bigger radiator and relocate a few wires to the ignition. If you have a car with A/C then the small block radiator might work. You will also have to think about the exhaust system as your hookup points will change. What rear do you have? If it has a 904 I would guess that it might have a 7-1/4 or 8-1/4 rear, neither built for big block power.

The 4-speed swap is another level or two up in difficulty from what I hear. I think Sherman sells a 4-speed hump and you will have to find the clutch/brake pedals and shifter. Likely very costly swap and your will have to do some welding. I would only try if I had a friend with experience doing it to help.

Good Luck, Tedd

by **Hans (72challenger)** » 16 Apr 2002 14:24

Interesting questions, I'm doing the same swap at the end of the year. Only from a 340 w/ 727 instead of 904. So I don't have to change my driveshaft although I do need another 727 trans for a big block. I already have the 26" radiator with new modern cores.

But maybe I can add some questions?
What about the external components of the engine, which of the following can directly swapped from a 340 to a 440:
- alternator triangle bracket, no.
- alternator adjuster bracket, yes.
- alternator, yes.
- steering pump, yes if you have the federal type of pump.
- steering pump bracket, no I quess.
- steering pump hoses, ?
- fuel pump, ? Take an electric one, fits always.
- carb, yes if it's big enough.
- motor mounts, no as stated before.
- pulleys, ??
- stock fan, yes I quess.
- radiator hoses, depends on which BB waterpump you have. Passenger side inlet will fit cause radiator outlet is fitted at the passenger side with a 340.
- ground cable from bat. to block, yes make it fit if needed.

Anything I forgot? Put it in.

Can't help you with the trans questions, have no clue about that.

by **Dave-R (Roppa440)** » 16 Apr 2002 15:27

Apart from the change in bellhousing I think the small block trans will work fine after beefing up with a B&M TransKit. Somebody shoot me down if I am wrong.

by **Dave-R (Roppa440)** » 16 Apr 2002 15:28

Or does the input shaft have fewer splines???....

by **Hans (72challenger)** » 16 Apr 2002 17:50

Really can't tell you Dave, I'm not into the transmissions. Yet...

But can you maybe give your opinion about the things I put in the previous message Dave? (pulleys, fan etc) Cause right now I'm busy collecting all the parts I need for the swap and tuning of the 440 so the further I know what I need to buy, the better. This so I can spread the total cost.

by **Dave-R (Roppa440)** » 16 Apr 2002 18:55

I really don't know Hans. It has been 13 years since I had a small block! But I doubt there is very much at all that is the same on both blocks. If anything.

by **Tedd Lister (Teddl)** » 17 Apr 2002 1:45

As far as the bolt on engine parts, the pulleys can be tricky because of the various types used depending on options. Another thing I was told is that cast versus steel crank engines use a different main pulley. I had trouble as my 440 came out of a manual steering car and was going into a power steering car. Pulley hunting became quite a pain, best to find an engine with all the pulleys you need. I finally found a 383 in the yard and took the whole set.
The power steering pumps came in two configurations, and I think they were not BB vs SB. Year one catalog is great to use for these issues when finding parts that fit both. Then go to the yard and get one off a 318.
Tedd

by **Mark VW (74mvw)** » 17 Apr 2002 14:55

hi guys,
going through this right now. With the exception of the hoses to the box, power steering pumps are interchangeable, brackets need to be from BB though, same for alternator. driveshaft to tranny yoke is larger than small blk, i had to find and shorten a new driveshaft. not sure but i don't think you can change the bell on the tranny case. BB tranny will be needed.

by **Dave-R (Roppa440)** » 17 Apr 2002 15:53

That rings a bell with me now about the bell housing. I remember now that it is all one casting with the rest of the trans. Thanks Mark.

by **Hans (72challenger)** » 17 Apr 2002 16:05

Do I understand it right if you said I need another driveshaft although I'm changing from SB/727 to BB/727 Mark? So this means the BB727 housing is bigger 'at all sides'? Didn't know that, thougt they were the same besides the housing where the trans meets the BB. Or does what you said only count for a SB/906 to BB/727 swap.

by **Christer (Christer)** » 17 Apr 2002 19:25

Length of A-727 (except yoke): 34.39"
Length of A-904, A-998, A999 (except yoke): 30.58"
Hope this helps!

by **Johnny D (Johnnyd)** » 18 Apr 2002 0:16

In addition to changing the yoke, I had to have my small block driveshaft shortened about 4" (just as Christer is describing above).

by **Mark VW (74mvw)** » 19 Apr 2002 12:14

not sure about sb 727 tailshafts, haven't messed with one lately, my driveshaft was 904. the yoke is larger on the bb727. the length of the driveshaft is 49.89 and needs to shorten to 46.5"
according to my tech manuals. i used my driveshaft, had it shortened from the frontside due to the tappered rear, and swapped the yoke from an older shaft. a shop near me charges about $40 to do the shortening and rebalance.

by **John P (Blue)** » 19 Apr 2002 19:34

727 tailshafts are all the same length, in fact the entire transmission is the same length, SB or BB. you can transplant the entire internals from a SB 727 into a big block case if you wish, or vice versa, it's all basically the same stuff in there! Early '60's trans have a different front spline pattern but as long as you have the matching convertor these are usable too. the SB top pulley will hit the mounting bolts when fitted to a BB water pump by the way!

by **Hans (72challenger)** » 20 Apr 2002 6:10

Glad to hear that John, now I know it for sure. I don't have to mess with the driveshaft when swapping from a 340/727 to a 440/727. Thanks

by **Frank V (Rtse)** » 20 Apr 2002 13:24

seems i talked w/a guy on a swap from auto to standard in the trans section you might look there too