I'm in the process of upgrading the engine of my 1985 Camaro IROC and I'm not sure what to do about the transmission.

The engine I'm putting in the car will be a 383 with roughly 400 HP, give or take a few. The trans thats in the car now is a 4L60 that was rebuilt back in 2000. From everything I've read, this trans most likely will not hold up to that kind of power, so I'm trying to figure out what to do. I'm not going to be running slicks of any kind and the car will mostly street driven though I might take it to the strip 1-2 times a year. Maybe.

The first question is, what am I risking by running it on the current trans? I mean, if I just keep what's in it and then it ends up dying, what could happen (other than towing/down time while being fixed)? If the trans goes, can it break the engine? I'm thinking that I might just drive the car as-is until I have to do something about the trans, but I don't want to do that if the trans going is going to cost me $$$ in other repairs.

Now...what is a good way to go to upgrade the trans? I've read the posts about the rebuild kits available, but I'd probably have to pay someone to install it so I'm not sure that it's very cost effective. I also found that you can buy some aftermarket transmissions (for example, from Summit Racing) for around $1,500 for the 4L60 (or 700R4, which I believe are the same) which seems pricey, and I'm not sure if they are built to withstand so much power or if they are just a stock replacement. They also have TH350 and TH400 models that are quite a bit cheaper but I'm not sure if going to one of those models is a good idea or not. To sum up, I'm pretty much lost. Ideas and suggestions?

One more question...in doing my research, I see that some automatic transmissions say "Forward shifting pattern" and others say "Reverse shifting pattern" - what does this mean?

Thanks in advance for all responses.

 

Stay with the 700r4. Dana can help you.
http://www.700r4l60e.com/

 

The kit looks like it's about $550 or so. I called my local trans shop (guy that I've known for years and have done a ton of work with), he said $350 to do a bench install, which means I'd have to pull the trans and reinstall. That makes it a $900 job. Sound about right? I have no issue pulling the trans but I don't think I want to tackle rebuilding it myself.

Definitely the cheapest I've found, seems like the way to go. That leads me back to my original question...do it now, while the engine is out or wait until (if?) it breaks? How much time and labor do I save myself if I do this while the engine is out versus waiting until it's back in?

 

Id say do it no if you have the coin. your guna do it either way. maybe slap a converter in it while its apart.

 

Either get the 5 pinion planets, 13 vane pump, beast sun shell and all the extra goodies when you pull it or get a 4l80e and a controller and you are done. The 4l80e will handle close to 1000HP when built right and you will not break it. I have broken SEVERAL 700r4 with all the goodies I mentioned. I bought a 93 4l80e but have to make a crossmember and get a controller or convert to OBDII system for my engine which will control the trans.