I've got some info here that could help some people mating an older 4l60e or other tansmissions to the LS motors. This info was taken from the "LS1 engine kit installation guide". Hope this helps. "PN 12563136 flexplate, for 300mm bolt circle torque converter, originally used with camaro/firebird and c/k truck with 4l60e transmission. This flexplate is "dished" and uses bolts pn 12553332. PN 12551367 flexplate, for 4l80e transmission or 6 lug converter. This flexplate is flat, and requires a special spacer (pn 12563532) and bolts (pn 12563533) included with the flexplate assembly. The spacer is installed between the flexplate and crankshaft flange. NOTE: This flexplate has a six-lug bolt pattern for use with THM 400 and 4l80e transmissions. The converter mounting holes must be modified for use with Gen 1 and Gen 2 converters with 298mm bolt patterns." The manual also says that with the "flat" flexplate, early 4l60's, 700r4, THM400, and THM350 transmissions can be used with the spacer. Hope this info helps!

 

where did you get this guide at i would realy like to get this info for later use on my s-10 blazer i building

 

I got it from Scoggin Dickey, it's in the GM performance parts catalog. You can basically get it from any GM performance parts dealers, pn 88959384 $15.00 or so, can't remember exactly. Very good guide with lots of info and some wiring diagrams.

 

I have one, information is based on a 98 LS1 Crate engine, a standalone (kit) wiring harness and 98' PCM. It used to cost about $40+, but has dropped to about $11.00 now.

If you are using another year engine, wiring and PCM, you will have to check the wiring and pin out for that year as compared to the 98' crate kit wiring.

But the other stuff is good !

 

It is pretty useful, along with Will Handzel's book (How to Build High Performance LS1's or something like that).

'JustDreamin'

 

nice thanks alot, this will help me alot, got an 87 s-10 blazer putting ls into it with 700r4, just got truck out of paint shop, an getting excited about doing this.

 

Sure now that I have finnished my swap they drop the price . I didn`t buy it anyway since it was so expensive, but now that it`s under $15 mabey I`ll buy it just for the heck of it.

 

I picked up a used GM dual pattern flexplate and spacer from an ad on this board to mate to my TCI 2004R spline convertor and transmission. Everything bolted together OK but the spacer was not long enough to engage the nose of the convertor. Buying a new TCI flexplate solved the problem without needing a spacer and also took care of that extra $200 I had laying around. One point though, I am reading that you install the spacer and then the flexplate. I do not believe this is correct, since anytime you move the flexplate out from the mating surface of the crank, the starter gear teeth will not meet the flexplate ring gear teeth. The spacer has to go on after the flexplate is properly seated doesn't it?

 

$40 is too much before the swap and now you'll buy it when you're done...haha

 

I am done with this swap, but I have a feeling this won`t be the last LSx swap I do . I really like these motors now. Plus I was very time limited and cash limited when I did the swap. When I finnished I was glad I didn`t spend that $40 for the book or I wouldn`t have been able to put a full tank of gas in the car right away . I did my swap on a college students budget, I didn`t even buy a service manual for the motor, I just copied the wiring diagrams out of a chiltons manual from the library........and the PCM pins on the diagram weren`t even numbered or in order .

 

I think this info should be added to the Conversion sticky at the top.

Thanks!

 

Hi guys ! I'am new here and just got a 97 or 98 not sure 5.7 LS1 vortec motor ,and wanting to set it in my old 78 chevy 1/2 ton. have a th350 trans in it now. What do I need in the way of a flexplate to mount it against the 5.7 LS1 ? also will my old starter still workon this combo.? and how about the water pump off my old motor(84-350)? This motor I got a hold of has roller lifters an one of them has come apart, and missing a push rod plan on dropping the oil pan and check it for loose parts . I want to run a carb and HEI dist, I know I need a intake manifold for it ,any thing else? have very limited funds for this project. just looking to get my old chevy back on the road, Will appreciate any advice given. Thanks old retired mechanic Slim

 

The trans forums should have info as well as GMPP, trans-dapt and other sites, NOTHING Gen I fits Gen III. You dont need a distributor to carb your motor, an msd 6010 will handle that. This site has tons of very useful, endless info, do a lot of searching Slim and good luck with you're swap. My funds are very limited, but if they were'nt i'd still be moving at a snails pace with my swap because i'm still gathering info, like you i have my motor, i have the trans and other parts as well. I'm learning these Gen III's as much as possible FIRST though.

 

The only time you put the spacer behind the flexplate is on a flat flexplate. On the dished flexplates, the spacer goes on last.