Originally Posted by bjamick

I figured i would just post up all the parts that i used in my swap to the TH350. I will add part numbers also because i have been seeing alot of post about TH350's. Maybe if people use the search function this will stop all the post about the TH350s if we compose alot of info in here.

First off you need to either buy a TH350 that is already built, or buy a rebuildable core from a junkyard or where ever you prefer. I personally bought mine off ebay with all the Heavy duty parts inside and with a trans brake and all the goodies. If you order a TH350 with a Full manual valve body this will mean that in order for the transmission to shift you will have to do it!!!

http://www.performabuilt.com/ Link to TH350 transmissions

A forward manual valve body will go like this: P R N 3 2 1
A reverse manual valve body will go like this: P R N 1 2 3

Any TH350 can be made with either a forward or reverse manual valve body, all you have to do is make sure that you get a shifter that will comply with which ever you get..

When you go to buy your Transmission, you want to make sure and positive that you get the long tail shaft (9") so you can still use your stock driveshaft. If you go with a short tailshaft then you will have to have a new driveshaft cut. So make sure and specify whichever you want at the time of purchase.

Parts Needed.
With the TH350 the stock VSS (Vehicle Speed Sensor) from the 4L60E will not work and a new conversion piece will be needed. Alot of people go with Rossler to get this part but since they are a non sponsor i will not post a link to their site. Just make sure you are ready to shell out around $250 for the whole setup .
OR
You can follow SUX2BU's write up on the free way to make the speedo work with the TH350. Here is the link to his thread just in case you are wondering what im talking about. https://ls1tech.com/forums/automatic-transmission/479729-free-way-get-speedo-work-th350-th400.html


You will also need a new crossmember preferably with the torque arm relocation on it. I went with BMR and everything went pretty well with it, i highly recommend this product. http://www.bmrfabrication.com/F-bodyChassis.htm
On the BMR link, the crossmember you need will be at the very bottom of the page, look for 98-02 F-Body with TH350.
Im not for sure if UMI or Spohn carries the crossmembers i've just always heard of BMR.

Also a new transmission Dipstick will be needed, as for me i went with the MadMan dipstick from thunder racing.

http://www.thunderracing.com/catalog...&sid=743#P5262

As for the install of that dipstick, it only took me maybe 5min at the most, start to finish. Some people use the flexible Lokar and i believe if you go this route the dipstick needs to be 36" i believe but dont hold me to that. I personally would not go the Lokar route just bc of the bad reviews i've heard about how long it takes to put fluid in. Just search around a bit and look at the different thoughts other people have had with the 2.

As for the o2 sensors i have heard that they wouldn't work with the TH350. I'm not for sure why they said this but maybe if your running just that certain type of headers then maybe then it wont clear. As for me i am running SLP long tubes and my O2's clear with room to spare so this is just my experience and as i said maybe with a different set of headers the o2 sensor may need to be relocated.

Now on to the Torque Converter. Either you will have to buy a new TCI flexplate that will work with the TH350 converter, or you can have a Torque converter company such as Yank, Vigilante, or TCI or whoever you prefer to make you a custom converter that will work with the stock LS1 flexplate and also with the TH350.
If you have a 98 model F-Body then your stock flexplate will have 2 sets of holes in it. One of those sets will work with the TH350 converter. I believe you will just need tell the Converter company that you are putting this in an LS1 so that way they will know to extend the output shaft on the converter so it will reach the crank.

New coolant lines for the tranny will need to be ran, as for the stock lines are about 4 inches to long.
To add to this part i would like to suggest that if you are running a pretty large stall 3500+ the i would get a nice trans cooler but even if you have a 3000 stall i would still suggest getting one because they are just cheap insurance.

I suggest the B&M 24000GVM Here is a LINK
http://www.ls1speed.com/catagory.cfm...y=Transmission

As for the coolant lines just measure about how much hose or metal line you will need and just go to a parts store and they should have whatever type of line you want to run. I've heard of people using Metal Break line bc its kinda flexible and wont corrode over time. As for me i will prob just use some fuel line so that away it wont corrode either from the trans fluid.

You will need to get a new Transmission mount as the old one will not work with the new crossmember or transmission. I just went to my local Advance auto parts and asked for a transmission mount for a 1977 camaro and it worked perfectly.

You will need to get your tuner to turn everything off that has to do with the transmission bc now the transmission is controlled by YOU and not a computer .



Also some of the bellhousing bolts will not be used, as for the 4L60E had like 8 bolts holding it on to the block the TH350 only uses i think 5 or 6 can't really remember off the top of my head. Just dont be worried when you have extra hardware



I think that about sums it up, but if i have forgot something then let me know and ill add it..
Your welcome guys

Thanks
B.J.