Hey guys,

I've been reading through the LS forum here while doing my research on what kind of swap I want to do ( 406sbc or LSX), and can't find the answer I"m looking for.

I would keep my 700R, and I know I'll need to get the space, but it uses a 153 tooth flexplate. Will this flexplate work with the spacer needed or do I need to go up to the 168(?) tooth flexplate that I've been reading about on here?

 

this may help

http://ls1tech.com/forums/conversion...-ls1-swap.html

 

Get the LQ4 / 4L80E flexplate with spacer, then assemble everything, then see if the flexplate needs the holes elongated or redrilled for your torque converter.

 

Your 700R4 flexplate is 163 tooth, you only need the crank adapter to make it work with that trans

 

I actually have a 153 Tooth flexplate, not 163 tooth.

 

Strange, never heard of a flexplate that small

Anyhow, 4L60E dish and 4L80E flat with adapter flexplates are common and inexpensive. Grab a replacement and dont worry about it

 

Ok. good to know I can just get one of those two and they'll bolt up.

This thread here where I was talking about my engine buid, post 18 has my build sheet which has the flex plate listed. I verified the p/n and it's this flexplate.

 

Learned something new

For future reference, any flywheel/flexplate that will bolt up to a 1pc RMS SBC will also bolt up to a common LSx crank. Depth changes, so using a spacer/adapter may or may not be needed

 

153 is standard SBC all through the '80s. 168 was earlier SBC, all BBC, and all LSx

 

I will most likely switch because the starter on an LSX is different thatn the old SBC starter right? That is the main driving factor for the number of flexplate/flywheel teeth isn't it?

 

168 flywheels were used in trucks til 2002 iirc.

 

LSx starters are different

There isnt a cost effective LSx starter that can reach a 153 tooth fly/flex which is the main limiter for T5 users

 

Fair enough. I'll have to cost-compare the 153 tooth LS starter vs a different flexplate and adapter and LS normal starter.

 

http://ls1tech.com/forums/conversion...-flywheel.html

You're better off swapping the flexplate

 

Ouch...no kidding.

 

Oh, yeah, sorry. Anyway, those flexplates are different from BBC 168-tooth flexplates, except the old 2-pc RMS, then except 400 / 454, and those 2 differ, and all of those differ from 168-tooth LSx flexplates.
No matter what adapters you find, you still need either of the 2 LSx flexplates. One is dished, one is flat.
I got a new flat one for an LQ4 / 4L80E, which to my surprise included a 0.400"-thick aluminum spacer and longer bolts, to go with my '96 4L60E, and that worked out perfectly.
The dished LM7 / 4L60E style supposedly just needs a Hughes pilot adapter, or if you're planning serious HP, then TCI makes a SFI-approved flexplate for the LSx.

 

A Gen I one-piece RMS flexplate will have the counterweight on it (which is shown in the link to the Pioneer part). LS engines don't use the counterweight.

cosmick has it right. Get an LS flexplate made to mate to an earlier TH700/4L60. (something like this http://www.summitracing.com/parts/ad...make/chevrolet )

(pocket, surprised you didn't know the Gen I SBC flexplates were 153- and 168-tooth - approximately 12-3/4" & 14", respectively.)

 

All the auto flexplates Ive messed with were 168 tooth. 700R4, 4L60E, 4L80E, TH350/400

The only 153 tooth rings Ive put my hands on were manuals. T5's and various 4 spds

 

All I know when I was building the motor, the flex plate I got from the builder was a 153 tooth. It fit, no shims needed on the starter, so I was a logical next step to see if it was something I could use with the adapter or not.