A500 vs.A518 ?

[stu in wichita]

This has probably been discussed on this forum, but I couldn't find much on the A500. I'm changing to an overdrive tranny in my '74 Challenger (318/A904). I'm hoping the answers to a few questions will help me make up my mind.

1. I understand the A518 is based on the 727 and the A500 is based on the 904. Will the A500 require less modification than the A518, or are they both about the same externally? How about weight differences between them?

2. From what I read, it looks like most people picked the A518 based on it being stronger. For my purposes, I'm sure that either one is stout enough. Is there any other factors that I should consider?

3. It looks like all A500's use the lockup torque converter. I've heard it only drops about 50 rpm when it engages. That seems like a lot of complication and extra expense for a small benefit, so maybe A518 without the lockup would be better for me. Am I missing something?

4. Whatever I decide, I'll probably need to get it rebuilt. Are rebuild costs about the same for either?

Thanks for any input.
-Stu

 

[burdar]

The RPM drop when the lockup is engaged would depend on how "loose" the convertor is. The looser the convertor, the more RPM drop you will get. I think the 500's were installed behind the 3.9V6 engines...the V8's got the 518. I would think that the V6 would have used a looser convertor to get the engine up into it's power band faster. Normally I think 500RPM is around what you see when the convertor locks up on a stock vehicle.

I had a 904 behind a 360 in a car I used to drag race. It held up just fine. You should be OK with a 500 as long as you aren't planning on making a huge amount of hp.

 

[moparleo]

Not a drop in. Lot of tunnel, cross member, transmission case mods required. Here is a little info on your project. There is a lot more info available on the net. Do your research before you start cutting.

Good luck.
http://www.transmissioncenter.net/SwapInformation.htm

 

[stu in wichita]

Thanks, I've seen that info and a few real detailed project posts. I know it's not a simple swap, but definitely within my abilities.

My main question is whether the 500 is physically different or smaller than the 518, or if the modifications are about the same for either one. My car isn't a candidate for a "correct" restoration, so cutting it doesn't give me heartburn. Still, the less I have to cut, the better. If the required mods are about the same, I'll probably go with the 518, since they seem to be easier to find.

My son and I rebuilt this Challenger about 15 years ago. It was worn out when we got it, he wore it out a second time. Now it's mine and I plan to drive it on road trips and wherever I feel like. If I have my way, I hope to wear it out again. Life is too short to drive boring cars!

Thanks for the help.
-Stu