I have a 68 d200 with a 318/727, 2wd. With 4.10 gears in the Dana 60, the little 318 is really buzzing on the freeway. I could swap some 3.54 gears in, but it would lose some of it's off the line snappiness. So I was thinking maybe swap in a 518 overdrive trans.
Does any one have some advice on this swap?

Thanks, Joel

Happy birthday young man. I have no exp with that but I have a 65 D100 that a big block/new process granny 4 sp is going into. there's a lot of room there. EDIT just me I would Keep It Simple Sam & swap a 360 & some taller gears in there (& maybe a 904).

Use a 1995 and earlier trans (pre-electronic RH vs RE designation) With the room under that rig it will be easy to bolt in.Possibly/probably a driveshaft mod and then add the switch for OD on/off.
RT

Thanks! The motor in this truck is so solid, I figured I should keep it.

Based on what I've read about swapping a 518 into a car the trans mount is further back which on a car requires modifying the center of the torsion bar cross member and tunnel surgery.

On a Sweptline you just have to slide the existing cross member back to where the mount will bolt in and drill new holes in the frame. Shorten the drive shaft and all the hard work is done.

Kevin

Yep. If you want to "wake up" the 318 don't use the A518.

A500, 42rh or 44rh: 904-based overdrives that don't suck as much power as the 727-based Turds.

Torqueflites

Is that an easy bolt in? Is it strong enough for a truck, and trailer towing?

Which one?

Since both have only ever been available in trucks, that probably have towed a few things too, I'd say yes. But there are updates that ought to be done.

Easy bolt in?

Define easy. With zero issues what so ever? No.

major hack? No.

Driveshaft will likely be too long. Cooling lines are larger. You need to control the lock up and OD. Stock shifter will work.

The A500 was pretty much just used in commuter vehicle. The A518 was used in real trucks.

As for od control, yes the easy way is a switch for od. But it can be made"automatic" with pressure switches.

Should bolt right up no problem.

There's been plenty of Dakotas and 1st Gen 150's that ran that transmission so, you'd have to look at the tow ratings on them and see if it matches your needs.

These Guys know their 904's and 44rh's:

SMR Overdrive Link

you answered your own question---the 518 will work fine with the 318----the 500 stock is not as strong as the 518-----the drag race guys pour alot of money into the 904,s to get 10 more HP to the rear wheels---dont sweat it----on the tranny brace slide it back till the front holes of the brace match the rear holes in the frame----drill 4 holes in the frame to match....

Nice sentiment for the racing forums but hardly germane for a hauling truck.

THere's a few junk 93 - 95 pickups and vans on craigslist around here.

do not get an electronically controlled one.

95 or older according to RTSRunner above.

Go with the 42RH aka A500. You can build it to hold plenty of power. Also, it has a 2.74 first gear vs. 518s 2.54. You can keep your 3.54 gears this way. SMR are great people, they have a kit and it will handle plenty of HP. I am building one now for a 318 (doing junkyard jewel style, just under 400hp) and the trans will hold up fine. PM me and I will forward you a link for info on installation. It is over on cuda-challengercom. Trans is also smaller, lighter, and takes less power to run. Member Gdonovan (I believe) has a no nonsense electric circuit to make it word great.

Nobody has asked what kind of budget is available for this. I'm sure SMR is great, but if their price for a complete transmission is anything like what they want for one of their B/RB to 518 adapters your wallet better be pretty heavy.

If you look around you can find a decent 518 with a converter relatively cheap. I put $1500 in mine and to put it behind a warmed over 360. I picked up the trans off of Craigslist for $300, spent $600 on it at the shop having it gone through, $100 in a B&M flex plate and another $500 in a Turbo Action converter. The shop even said it was a factory reman unit with few miles.

The above was seven years ago. This past Spring I lopped the bell of and used an Ultra-Bell to put it behind a 512ci big block. Still going strong.

If I were putting it something like your truck it could probably be done for under $500.

THis is just a stock daily driver type of truck. I was thinking $200 - $300 total budget. BUy a beater/junker for $300ish, yank the trans, sell some parts and the hulk to get most of my $ back, put a kit in it and bolt it in.

I'm new to small blocks and automatics.

Yeah, don't fall into the "somebody elses money" game many on Moparts like to play. Your plan will work, though I might give thought to having the trans gone thru if funds allow.

I will try to answer this in not such a negative way but I agree with Grizzly.

I did the 518 swap from a 904, for the overdrive. This was on a 14 sec 5.9L Magnum in a 4000lbs 87 Ram.

The original 904 with it's deep 1st and good efficiency seemed run good w 2.76's. No official numbers with this combo since the trans failed in a few weeks.

Swapped to a fresh hydraulic 518 with lockup and 3.55's. Truck had a taller 1st so a swap to 3.55 was absolutely necessary. Mileage seemed the same, high teens and the power was 15.0 @ 90.
The 518 eventually lost overdrive but I continued to drive it for a year. Without the overdrive my highway cruising speed changed from 120km/hr to 100km/hr which even without the OD, the lower speed made my mileage calculations spit out the same high teen numbers.

Up to this point, I still liked the 518 but a switch to a NV3500 5 speed manual transmission made me realize Grizzly is correct.
The 3500 does not have good ratios for racing but the truck went 14.7 at 93mph. To me this is HUGE. The mileage also increased to low 20's, again huge.

Those are solid numbers for you guys to soak in but some things can not be put in numbers like a bridge near my house. I had to switch the lock up OFF and 4rth gear OFF to comfortably climb it with the 518. Even though the NV3500 had a similar 5th gear, I could easily climb it in 5th. Same for towing a car. I would try to tow in 4rth with the 518 but it struggled so often I'd let her rev out and just tow in 3rd but the NV3500 had no problems towing in 5th gear.