transamfreak01

iTrader: (8)

So I ordered a flex plate from a sponsor on here and when I got it in the mail it says TCI 399754 for 4l80e..... Now here's my problem.... I have a 408 with a th400. I called them and they said it works. Does anyone else have any insight on this bc I want to be sure before I put this on and put the motor back in the car.

Circle-D

iTrader: (21)

Depends on what bolt pattern the converter has. You can do a quick test, set the flexplate onto the converter to make sure the holes line up. The 399754 has 6 holes on the big 11.5" bolt circle. Other thing you need to worry about is the converter pilot, you might need an extension if the converter was built with the normal TH400 offset.

Chris

transamfreak01

iTrader: (8)

Well I haven't even ordered a converter yet . The car is all taken apart and just a roller right now. I just didn't want to slap the flex plate on before I new and then end up having problems. The car also has a 91mm turbo. So i just need a little insight before I order the converter from you guys.

Circle-D

iTrader: (21)

OK, we can fit that flexplate - no problem. Wen you order just let us know you have the 399754 and we will use the correct billet front.

Chris

transamfreak01

iTrader: (8)

Awesome. Would it be better for me to return this and get a different one or would this be fine?

Circle-D

iTrader: (21)

That one is fine... we have a few different options we can use. We can discuss the pros and cons of each when you call.

Chris

M.BOZZ

iTrader: (14)

I just went threw this problem, there is two flex plates. The you have which is a 11.5 space between the converter bolts and the other one is a 11. 1/4, just like stated above just let them know what the part number is on the plate, and will need a spacer

transamfreak01

iTrader: (8)

Wait so I'm going to need to buy a spacer? Screw that. I am not a happy camper now. I might just have them send me the other one.

Circle-D_Brian

Because of our custom CNC capability, we would not need to use a spacer. Ask for our LS dual front cover. This incorporates the long LS pilot with 6 lugs on the 11.5" big gm pattern. Have your cake and eat it too.

-Brian

transamfreak01

iTrader: (8)

Ah you guys are awesome Brian lol. You will be hearing from me very soon

mrvedit

Just to clarify, the need for a spacer has nothing to do with the choice of flexplate. The LS crank (with a few exceptions) is about 1" shorter than a SBC/BBC crank with respect to the back of the block. Hence the need for a spacer when using a trans originally designed for SBC or BBC. GM makes the spacer (and longer bolts) which bolts on after the flexplate and provides a solid mounting area for the converter's pilot. GM uses it in some applications.

CircleD's ability to make a custom converter (at little or no extra cost) that doesn't need a spacer and has the desired mounting holes is one of many advantages of getting a custom converter instead of an off-the-shelf one.

However, if you are think you might sell that converter some day, I would suggest getting a stock pilot length and installing the GM spacer. I think it would be easier to sell a stock TH400 converter than a custom one that would only fit LS engines. Obviously your call.

transamfreak01

iTrader: (8)

Mrvedit thanks a lot for clearing a lot of that up for me. What you said makes a lot of sense. I would have not thought about something like that. I'll be ordering one soon and as soon as I do I will be starting a build thread. Thanks again