fasteddi

iTrader: (2)

Another work in progress but I swapped out my 700r4 to a Th350 a year back and wanted to show the complexity and what all needed to be done
My reasons for the swap are simple. A shorter step between 1st and 2nd gear, which the 700r4 is just terrible at(ATTACHED IS A GEAR RATIO CHART VS TRANS). 2nd a Th350 is a lower cost trans to build up if you don't mind loosing OD(its not my DD and obvously my car is a bracket car at heart). Lastly for us 60 degree V6's, we cant just go buy a good tq converter. The aftermarket is horrible and basically non existant without a custom converter. Having the Th350 allows for a lower cost, 250-350 dollar range, good quality converters.


Step one finding a trans
This is simple really. These things are all over, stock and modified ones. You will definitly want a 9 inch tail transmission though. This allows you to retain your stock driveshaft. Makes the swap easier and lower cost by far. So really just find one that has a 9 inch tail and that is a good starting point. I would get more indepth with this but it has been covered a million times over and a search of our forums on what TH350s will work well, will show you a ton of information


Step two remove your old trans
Get that old thing out of there. Only things you need to retain is the clam shell mount for the Tq arm, the vss wire and connector from the ecm harness, the trans cooler lines. (one thing i didnt keep but in your case you may, is the shifter and the shifter cable. I use a B&M Megashifter).


Step three parts list
This you will need(a adapter plate from speedway motors to adapt your Th350 to a 60 degree V6 block)
http://www.speedwaymotors.com/60-Deg...late,3280.html

This you might need depending on if you want this or another adapter. This puppy will convert the mechanical speedo attachment on the Th350 to the Digital Vss signal you ecm wants to see. In my case(1990+) it wants to see 4k pulse per mile. If you have a older pre 1990 Fbody call them and they may be able to help you out. I ran this for 1 year, no issues, very accurate.
http://tpiparts.net/inc/sdetail/7587

IF your not wanting to fabricate too much this kit works well. This will allow for the trans to bolt right up to your existing trans cross member and also allow for a easy installation of the clam shell mount for the tq arm.
(I need to find the link for this still, I have a B&M but would rather suggest the Hurst branded one.)

This is another item you may not need but I got one and it made the install easier. Its a flexible dipstick for the Th350. 18 inches in length fits perfect and looks nice at the same time
http://www.jegs.com/i/Trans+Dapt/969/8138/10002/-1

There is a grey area if you want to use the stock shifter or not with a Th350 which is now a 3 speed instead of your 700r4 that is a 4 speed. I Got a megashifter for basically nothing so I went with it. I also run a reverse full manual valve body so I need a ratchet or gate shifter anyways for... absolutly no missed shifts when racing
http://streetperformanceusa.com/i-15...4C8RoCGNTw_wcB

Now you would just need some assorted items such as grade 5 or 8 bolts(grab them at Lowes or Napa when needed), make sure to have a grinder on hand, and basic hand tools. Be sure that what ever trans you have though is in good shape when you toss it in so that you dont have to tear it out 10 minuets after you put it in the car.

fasteddi

iTrader: (2)

Step four lets start grinding out some metal
Attached below shows a good picture of where you need to grind. You can see that the adapter plate will literally bolt right onto the block before you toss on the new th350 trans. In order for those bolts that will attatch the plate to the block you need to slightly grind some of the aluminum off the TH350 case to make room.

Now the same is true for the bolts that attach the TH350 to the adapter plate, you will need to slightly grind the block in a few spots as well. Trust me when I say you will be able to tell where and how much you will have to grid away when doing this project. Pics below to help explain.

Also you can reuse all the old trans to block bolts you had but will need to shorten them up. So cut them down. Measure how much you need to so you don't ruin the bolts. The reason for shorting them is because they will bottom out into the block way before they ever tighten up to the adapter plate. As before these bolts were to attach the trans to the block, now they are used to attach the much thinner adapter plate to the block. Pics below help you understand what bolts they are. They are the block ones that are cut down.

Now you need to toss on that adapter for the tq converter pilot. This is so that the pilot on the new TH350 tq converter can fit into the crank on the V6. Its the aluminum adapter you see on the tq convert er on the pics below.

Now you need to work on your flex plate. You will see that the bolt holes just don't line up perfect. So you will have to oblong the holes out sightly. Try your best to evenly do this and make the holes all the same size. What I did was have the flex plate still on the engine, I then held up the tq converter with the pilot adapter still on and push the adapter pilot into the crank, then the tq converter will be flush with the flex plate so you can mark it. I then marked where the holes should be at with a sharpie. Then took off the flex plate and started to oblong out the holes with a carbide tip burr. This took a little bit of time from taking off the plate then grinding then putting it back to check the holes but it did work well. Eventually you will be able to mount up the tq converter to the flex plate and see that it mounts up just right. Pics below to show the holes

The last part of grinding is...IF you have a dual bolt pattern converter such as the Freakshow Converter I have, the mounting pad sicks out too far and would hit the starter if it was left as is. You can see in a pic below how close it is to the outer teeth of the flex plate. What you need to do, and be careful as the tq converter is balanced, is you need to take some material off each pad with a grinder. Be as careful as you can to take the same amount of material off each pad! You need to take just enough of that the converter pad is below the teeth of the flex plate. It is literally 1/8 of a inch you need to take off. Even if you don't have a dual bolt patter converter this is still something you need to double check and make sure you won't have a clearance issue.

Next
Once you are done grinding the block areas, the bell housing, making the oblong flex plate holes, you are about ready to toss it all together. What I did when i tossed on the adapter plate, was tack weld the top two bolts that will be bolting from the adapter plate to the transmission. Just tack the back side(the head of the bolt) What this does is make it much easier to install the trans as the bolts will act as guide pins.

Just remember, toss the flex plate back on the engine, you then bolt the adapter plate to the block, then toss the pilot adapter on the tq converter, toss the converter in the trans, then lift up the trans and bolt it all up. Then once you have it up there and mounted, with the trans still on the jack, you can toss on all of your trans mounts and also the th350 kit adapter. It requires taking off the bolts for the tail but i did it when the trans was up in the air with no problems at all.

Once you have the trans tossed in, its just bolt stuff up at this point. Once again I bought a th350 swap kit for a 82-92 Fbody. So using this allows the Tq arm and the difference in trans mount locations to be easily adapted. It comes with instructions so just follow them and it will all go in smooth

Maverick H1L

iTrader: (8)

fasteddi, if I may...

FYI, the TH350 and the T-5 use the same speedo parts. Although it might not be the easiest thing in the world to find a T-5 90-92 speed sensor. And apparently, if the given application requires the drive gear on the output shaft to be the purple 7-tooth, those are few and far between (3.42 uses purple 7-tooth drive and 18-tooth white driven gears).

:edit: And the bolts on our cars are metric, except for the steering gearbox mount screws (ask how I found that out ). Should be grade 8.8 minimum with 9.X and 10.9 preferred.

fasteddi

iTrader: (2)

Good call. Yea I have never messed with a t5 before.

As for the bolts the stock ones I reused where 8.8 (iirc) metric. The others for the th350 to the adapter plate are grade 8 sae in my case and also the tq converter to flex plate are sae grade 8 as well.

project89

iTrader: (1)

ill add some pictures of my modified stock crossmember , and tq arm mount to this for ya next time i have my car on the lift .

2 small pieces of flat stock or plate and a lil bit of welding lets u reuse the stock xmember for the trans and converter it to a xmember mounted tq arm saving u 100-250$'s

34blazer

Can you possibly get some dimensions of the crank pilot adapter? Speedway motors doesn't have the adapter plate anymore, just called and they don't know when they will have more in stock. So I may have to make my own.

Six_Shooter

iTrader: (2)

Added to FAQ.

fasteddi

iTrader: (2)

Yes i will get you some dimensions asap this week.