I've got an A518 I'd like to swap into my '71 Swinger.

When searching for swap ideas I came across this crossmember. It says there are no modifications required to the floor? Has anyone here tried it?


http://store.uscartool.com/67-75-A-Body-518-Crossmember-Kit_p_141.html

I made my own xmember for my 68 Charger, there is quite a bit of mods to the floor pan & torsion bar Xmember for the A518, I would not think that an A body would have more room.

You have pics of the floor mods?

I thought crossmember & x member was the only mods needed

Everything I've read has shown extensive mods, here's a whole build thread......

https://www.forabodiesonly.com/mopar/threads/42rh-a-500-in-a-duster-with-pictures.178459/

I know one guy that did it to his Duster and he was pretty unhappy about how much it slowed his car down after doing all that work. I believe it has a .69 overdrive which is better than the .78 Gearvendors overdrive but the GV doesn't slow the car down.

CRT might have some products to make the 518 more efficient.

How much et did he lose

Your gonna be cutting the tunnel... the 518 is
big.. I run a 518 in my Rampage but the whole
floor is custom

I dont have any, but on the floor it is all hammer work,most on the driver side,my factory console still works. The Xmember hump in the floor board has to be raised,if not done the driveshaft angles become a problem.

B-bodies the crossmember center has to be modified. In e-bodies, the crossmember a couple inches back and doesn't need to be cut, just a tight fir with the speedo. I've never done an a-body, not sure how far back the crossmember is vs e and b.

I've always made my own vs buying... well modified the original.

Did the A518-swap on my '73 Dart;
USCartool saying no mods are necessary is a big pile of BS.

- Lower crossmember needs to be modified. Best to use '80s GM mount.
- Upper crossmember needs to be removed and replaced by either curved flatstock or full left to right crossmember welding to floorboards.
- Tunnel needs a few hammerkisses in some places.
- Need longer speedometer cable.
- Larger diameter cooling lines needed.
- A518 tailhousing needs 1 or 2 ribs ground off on the sides.

I didn't gain any mpg in my daily driven A-body but the car did become more fun to drive.
Using 3.55 rear gears.

Sorry for the delay John, took me awhile to remember who it was.

I was wrong, the 518 is the only trans he's had in his white Duster, his name is Andy and I believe he's done business with you.

He thinks it is slowing him down as he's in the low 11's and thinks he should be high 10's. I think he plans to put a 904 or 727 in it soon, then he'll be able to tell exactly what the ET difference is. He said the 518 is also very heavy.


I would really like to try one on my next build if I can find an affordable trans and apply your cool new parts with it.

I have a 518 behind my Hemi. The 518 itself won't slow the car down with the exception of it's additional weight. Little or no impact on straight line performance.

As to the cross member, that one suffers from the same problem mine has. The mount is forward of the cross member which puts it in a leverage situation trying to twist the entire assembly. These 518s are heavy.

I intend to make a new cross member where the mount is centered under the cross member. There are 3 mounting holes on the tranny, so making a plate to position the mount directly under the cross member shouldn't be that big a deal.

Personally, I love the 518 and feel it is worth the trouble to fit it in my Cuda. Now, trying to get it in an A body might be a different matter.

No tunnel or other body/structural mods are required on 70 and later B and E bodies....maybe M bodies. All other body styles will require some tunnel mods to accommodate the wider tail of the A500/A518. This swap is totally worth it. By far, It is the best mod I've done to my Challenger. Bolts up like stock, stock linkage works well. Just need a custom crossmember...made my own.

The late model RX8 seats are a close second, the 5.7 Hemi.... not so much. I should have stroked and TBI'd a 360. Looks cool and has lots of power though.

When I built my Rampage I put a 518 in it.. when building the whole car it was fairly easy to put the
518 in it... its a tube chassis car thats a street rod... so its fairly easy to put any trans in it at the time..
with the OD in it I run a 4.10 gear also has a 416ci with injection

a 1970 B body will require the same as my 1968 Charger, it is a lot of work, yes the tunnel will need work

The part about the E and B-body being different has my attention. Since the k-frame is identical in both, the torsion bars the same and the frame crossmember the same, how? If so I got problems I installed b-body stuff in my 73 cuda and it all lines up