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LS2 w/TH350 Flexplate to Case Interference

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Old 06-22-2017, 09:12 PM
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RaG
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Default LS2 w/TH350 Flexplate to Case Interference

1st POST!

I've been working over the past few months to replace my Vortec 383 for an 05' Corvette LS2. No mods at this point just trying to get it in and running! Going into my 71 Chevelle.

See the pictures below, I have a slight interference with the ring gear on the flexplate and the TH350 case. The interference is on the passenger side near starter and the driver side has ample clearance. I've searched around and haven't stumbled upon another thread where someone had the same problem.

I did run the starter (but not start the engine; 3x 10sec intervals) in an attempt to see if the engine would produce some oil pressure on the HP tuners scanner. It did not, but that is another thread! I stopped trying to build oil pressure with cranking after hearing the noise and discovering the interference.

Possible Solution:
I'm thinking it is down to having to pull the transmission back from the engine and grinding down the problem spot (on the trans case) to add some clearance between the ring gear and the case. I would estimate the problem area on the case to be about 0.5" x 0.5".

To adapt the engine to the trans I used the following parts:
Dished Flexplate
Jegs.com 555-601080
(http://www.jegs.com/i/JEGS-Performan...01080/10002/-1)

Bolt-on Crankshaft Spacer Kit
Jegs.com 601010K
http://www.jegs.com/i/JEGS-Performan...1010K/10002/-1

The transmission is a TCI Turbo TH350 street fighter with a TCI Breakaway T/C. The T/C is dual pattern and bolts right up to the flexplate and slides into the crank spacer.

Any thoughts on the possible solution to the interference? Sound like a good idea or maybe it is something else?

Anyone else had this problem?
Attached Thumbnails LS2 w/TH350 Flexplate to Case Interference-20170622_193945.jpg   LS2 w/TH350 Flexplate to Case Interference-20170622_194554.jpg  
Old 06-29-2017, 06:56 AM
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A couple things, is the FW bolted to the crank, and then the spacer installed? prob have to be or the starter wouldn't match up. Usually that spacer is installed on the crank, then the "flat" 4L80E style FW is installed-most guys use the small round spacer with a curved FW and 350/400/80E style converter. The 350 orig used the smaller 153 tooth FW when it was used on SB's, but some guys are using them on LS engines.
In the second pic it looks like a small gap bet the block and trans, or is it just how the pic makes it look-be interesting to hear from 350 users, if they had that problem
Old 06-29-2017, 07:07 AM
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I had a 168t on my 355 and my current 406 with the t350 and never had interference issues.
Is the trans bolted to the engine?
Something is off. That "should" be perfectly centered when bolted to the engine regardless
of what engine type it's bolted to.



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