Not sure if you have a big or smallblock engine to put in front of it, but don't forget all 518 transmissions have a smallblock bellhousing.

A friend of mines 440 Duster is running 121 mph through the traps with a 518 with Ultrabell. Full street car with steel wheels and power steering.

Good catch, this will be behind a Gen III hemi so at least that part is figured out.

Thanx Polara Pete, I have fun with my D150, I am the original owner as I bought it new in 1992. It ran its lowest E.T. to date last weekend going 15.12 @ 87 mph with a 2.03 60ft but averages 15.20s-30s. I have been very successful with it with many round and eliminator wins, including r/u in Street at Chryslers at Carlisle back in July and a Win in Bracket 3 ( 14.00 and slower) at a Mopar Meet at my local track a few months ago.The 518 has never been apart ( only out a few years ago to have the shift kit installed) even after all these years of racing and towing as it used to be my tow vehicle.

Just a matter of time before it grenades. It's a shame Chrysler didn't build a better OD Unit. They were no doubt the weakest OD units of all Makes ever made. I know you can beef them up a bit but they won't take a beating especially behind a big block. Hell you can even make the Ford AOD stronger than the 518.I debated about putting a 200r4 behind my car but I was too proud to GM it. So I'm putting the 833 back in it.

Put the big 6 pinion planet in the OD out of a 48RE, add an extra strong spring and a diesel clutch pack with an extra clutch and it will be fine. I block the OD acumulator (the spring is usually broken anyhow)and open the feed passages in the case and VB to apply the OD quicker, seems to make OD go in and out quicker when you hit the button both timing and firmness. No reason chrysler should have let them leave the factory like the piece of crap they were but with minor mods they are very good.

A fellow club member has an original '70 Superbird with 426 Hemi and he runs the Aluminum case 833 with OD 4th gear to cruise to car shows...but he does not race it, of course. He saved the OEM 833 on the shelf so that when it comes time to cash in his "401-K" Superbird he can say it is numbers matching and mean it. Some years ago, he and several other club members drove the car from Everett, WA to Talladega, AL. There was an event to celebrate the NASCAR reunion for all the aero cars including the Phords. Most of the participants trailered their cars, but Bob Kropp (AKA SuperbirdBob) drove his. They were made to be driven, weren't they???

Just a matter of time before it grenades. [/quote]

Been driving it for two years now, it was built to be a true street car hence the back seat and power steering. It even has a flat hood.

He drives it to work and takes the kids out in it all the time.

Problem with that is the extra pressure has to be overcome when the OD is engaged and this robs apply pressure from the OD clutch pack along with putting extra load on the bearing that carries the spring pressure. This is what makes the Mopar OD trans inferior to most others.

do you have any pics of the feed passage mods ? is the 6 pinion planet a steel case ? i have never been inside a 518, but have been contemplating an ultrabel/518 build for a big block project.

Why not use the NAG1 5-speed transmission? I know the controller is expensive, but the transmissions are supposed to be pretty tough?

Someday, I need to get going on my 6.1L NAG1 transplant project...

I would like to use a nag-1 , but the controller I have read about has been deemed less than reliable by Dave Webber from Modern Muscle.

I do not know of an easy way to run a Nag-1 in the way that a 4l80E is run.

Since the new site "up date" I have not been able to post pics, I can't even get them off my phone onto the confuser any more! I have a ton of pics to share like this and how to tell if your magnum heads are gonna crack or not...

The 6 pinion planet is steel caged, there are heavier doody ball bearings also to take the load better.

so if I want to put a 518 in my 70 Cuda with a smallblock, what donor vehicle should I look for? What is the OD ratio? Will I need to make any modifications to the floorpan or crossmember, or just a shorter driveshaft?

You will have to do major surgery to the crossmember to get it to work. Not sure about the floor pan.

I had a 90 dodge pickup with overdrive that could be turned off.

I went the gear vendors route.

I have a 73 cuda 340 with an A500 which is the 904 version of the 727/518. I love the lower first gear and the OD which is simply turned on and off when in high range via a toggle switch. It is dimensionally the same as the 518 at the case to tailshaft overdrive split and rearward, and thus posed the same challenges at clearing the crossmember that the 518 will. I did not want to butcher my crossmember, but took a cutting wheel/grinder to clearance the tranny itself as much as I could stand, especially at the case to OD flange where there are pipethread pressure test plugs. I also "bulged" my floorpan and dented the upper crossmember a bit in a couple places where interference was still a problem. You can cut the lower crossmember cradle to weld in a new rear tranny mount system, or try and buy a GearVendors crossmember cradle and mount which is what I eventually did and run to this day. Did this mod in the late "90s and still using it today tho with a non lockup 904 hi stall converter and modified (additional clutch plate) front clutch and front pump system from a 904. I always wanted to do this with a 518 but could not find one and convinced myself the lower first gear ratio of the A500 was more suitable for getting my somewhat heavy Cuda out of the starting gate. I did shorten the driveshaft by about 2.75 inches as I recall and had to mess with drivelshaft angles a bit to prevent an annoying vibration. Love it and it was a worthwhile mod. Now I want an 8 speed!!!!