Flex plate confusion
Flex plate confusion I bought a 99 LS1 awhile back and have been compiling parts for my conversion ever since. I went to O'Rilieys and told them I needed a flex plate for a 99 TA. then I ordered the Flex plate spacer from GM. The Flex plate they gave me was completely flat meaning that the crank holes and the TC holes were all in the same plane. the TC holes perfectly matched my Powerglide Tranny that I am putting behind it but the Crank holes didn't line up with my LS1 crank. so I went back and told them they sold me the wrong plate. they told me that there was 2 part numbers for flex plates of that year make and model. and so I walked out with a different plate supposedly for a 99 TA with the 4L60E. Plate #2 matched the crank holes perfectly but None of the TC hole came close. and the TC holes are not in the same vertical plane as the Crank holes. I.E. this 2nd plate is actually dished. I drilled out new holes for my TC and this plate bolts up without the spacer there is about a 3/16" gap when I bolt the Glide up to the engine when the TC is totally seated so I feel like that is a normal amount to draw the TC back to the Flex plate. my confusion is do you think the 2nd plate is actually the dished 4L80E plate??? 
I guess I should just be happy that I have a combination that works, but now I have the spacer and didn't need to buy it.
I guess I should just be happy that I have a combination that works, but now I have the spacer and didn't need to buy it. 
TECH Regular
Joined: Jan 2010
Posts: 497
Likes: 4
are you certain that the TC hub is seating into the crankshaft? that is what the spacer is for, ive got mine all bolted up. LS engine to an older trans and all i had to do is open up the holes on the flexplate and it looks all good, but its not, after doing more research i still need the spacer.Look in the automatic transmission forums there is a couple very good threads there.
Or PM jay_lt4 , he will have the answer for you.
Or PM jay_lt4 , he will have the answer for you.
TECH Regular
Joined: Jan 2010
Posts: 497
Likes: 4
In my case it would be crank hub, Flexplate then spacer, But am going to use the Hughes performance Spacer instead of the GM spacer. Same consept just the gm needs to be bolted on and the Hughes just gets tapped into the crank hub.
The dished flexplate is the one you need, but you'll have to use a dremel on the holes for the torque convertor bolts. The Hughes spacer is a good idea. That's what I have on one of my cars.
