I know that this thread is a little old, but I was curious about the bolt pattern on the TH350. Does it bolt right up to the LS1, or most of the holes line up? I am guessing (since I have not seen a TH350 up close) that it does not have the bolt hole at 12 o'clock.

 

only five match up. two on each side and one in the upper left.

 

That's good enough for me.
This thread is very informative, thanks guys for putting this info up there.
TH350 here I come!!!!

 

Haha, I guess after that "professional shop" left out my two top bolts and the car ran fine like that for two years we decided we dont need no stinkin eight bolts. We'll get by just fine on six, lol.

 

I'm concerned about the speedo myself. From what I've been told, I would need a T-56 reluctor wheel and speed sensor to make my speedo on a TH350. Reason being is that the T-56 and 4L60E reluctor wheels are different due to the amount of teeth. Now again, I was told that the 4L60E's reluctor wheel will slide/press right onto the TH350's output shaft, but a T-56 will not and will need to be machined and that you cant use a 4L60E reluctor wheel because it will throw off the readings. Anyhow, I would like the speedo to work and need to know what parts I need to buy to take them to my tranny builder tomorrow morning to install. Thanks.

 

if u have and A4 and then go with a TH350 do u have to reprogram ur comp.
or not

 

When switching to a M6 program. In hp tuners the m6 gear caculator will not work if you have an a4 VSS on your th350/400

Open up an a4 file to caculate your tires and gears ect.
copy and paste these values from the gear caculator to your m6 file
VSS Pulses/mile
VSS Pulses/rev
VSS Output pulses/mile
Trans Revs/mile

 

HI ALL!! i just joined, and this site rocks! i was looking everywhere for help on what i should do w/ my elk i got rotting in the backyard! After seeing all this i think the LS1 is the way to go... I have a couple questions
1. The LS1 is rated at 310hp right? how much loss can i expect goin through the 350?
2. Should a plain rebuild of the old th350 be alright or should i go with Alto Red Eagle's Kit?

 

Is this it?

http://www.jegs.com/cgi-bin/ncommerc...34&prmenbr=361

 

That's what I used, fits perfectly

 

to the top

 

1) I lost around 70rwhp on the dyno (MTI SAE #'s), but didn't lose any ET at the track.

2) I built the first one with the plain clutches, steels, and auto-valvebody. I trashed it bad! I then went back with the Alto Red Eagle clutches and Koleen steels, and I bought an Art Carr manual valvebody. I have ran about 30 passes on it and some in 100 degree track temps and it hasn't seen over 160 degrees.

I would recommend the manual valvebody on the TH350 because it assures you that your at maximum line pressure all the time. It also does away with the governor and the vacuum modulator. Less to go wrong.

 

What flywheel did you guys use? One from a TH350 or the stock LS1?

 

subscribing...

 

I used the TCI SFI FW on mine. I also converted from and M6 th a TH350. Speed did the tune and the VSS is dead on. There are a few issues with converting to a pure M6 PCM program. The Skip Shift, Clutch Switch, and Backup Lights codes wil need to be deleted. I have the SES light on all the time due to this. Speed is going to tune these out.

 

good post. This is my next mod.