LS1 style engines to old style trans(th350, 400, 2004r, 700r4, 4l60e)
LS1 style engines to old style trans(th350, 400, 2004r, 700r4, 4l60e) someone make this a sticky
here are the facts about fitting an old style trans to the gen3 engines
1. the gm gen1,2 trans will bolt to the gen3 engines but you only use 5 bolts, the gen 3 engines do not use the middle bellhousing bolt on the pass side( no big deal)
2. you do not need a special flexplate, the curved 4.8,5.3,LS1- just need the t/c bolt holes ovaled out a bit and the 5.3 flex plates have a set of holes that match the small gm t/c bolt pattern perfect
- the 6.0 flat flex plate has the same t/c holes as the large gm pattern(th400 and most aftermarket th350 converters that have a dual t/c bolt pattern on them)
3. you need to use a crankshaft spacer when using a gen1,2 trans and converter there are 2 types:
- hughes gen3 crankshaft spacer part # hup-3795 $44 from summit/jegs, this spacer must be used with the curved 4.8,5.3,LS1 flexplates
- gm stock 6.0 crankshaft spacer 12563532 and longer bolts 12563533, this spacer can be used with either the flat or curved flexplate ( if using the curved style flexplate the flexplate goes on the crank first then the spacer goes on then the bolts, if using the flat 6.0 flexplate the spacer goes on the crankshaft first then the flexplate then the bolts)
i have used both style spacers, on several 5.3,LS1, 6.0 swaps and have not had any problems with either set up
here are the facts about fitting an old style trans to the gen3 engines
1. the gm gen1,2 trans will bolt to the gen3 engines but you only use 5 bolts, the gen 3 engines do not use the middle bellhousing bolt on the pass side( no big deal)
2. you do not need a special flexplate, the curved 4.8,5.3,LS1- just need the t/c bolt holes ovaled out a bit and the 5.3 flex plates have a set of holes that match the small gm t/c bolt pattern perfect
- the 6.0 flat flex plate has the same t/c holes as the large gm pattern(th400 and most aftermarket th350 converters that have a dual t/c bolt pattern on them)
3. you need to use a crankshaft spacer when using a gen1,2 trans and converter there are 2 types:
- hughes gen3 crankshaft spacer part # hup-3795 $44 from summit/jegs, this spacer must be used with the curved 4.8,5.3,LS1 flexplates
- gm stock 6.0 crankshaft spacer 12563532 and longer bolts 12563533, this spacer can be used with either the flat or curved flexplate ( if using the curved style flexplate the flexplate goes on the crank first then the spacer goes on then the bolts, if using the flat 6.0 flexplate the spacer goes on the crankshaft first then the flexplate then the bolts)
i have used both style spacers, on several 5.3,LS1, 6.0 swaps and have not had any problems with either set up
On The Tree
Joined: Sep 2005
Posts: 111
Likes: 0
hey great job!! I've been looking for this, will help alot. +1 for making it a sticky. What about T/C, isn't the 700 and 4L60E t/c the same? and what about TV cables (bowtie overdrives) ??Pictures may help make this a sticky!!
You also have the option to buy an LS1 converter built for a TH350/400 and not use any spacers at all. But it's good to see all the info in one place instead or reading through 10 pages of the sticky/FAQ above, so good write up 
.
Dan
.Dan
Originally Posted by jay_lt4
how do you get something sticky'd,, there are more post's about this same topic on here all the time, this is the plain simple answer to all the ls1/th350,400 questions
Just leave the part # for the adapter. just my .02
Originally Posted by Vcious04
Good luck making this a sticky and using summit/jegs info/pricing..
Just leave the part # for the adapter. just my .02
Just leave the part # for the adapter. just my .02
Very good info though, I def learned a bit!
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Originally Posted by the_merv
What Converters can you use though.. if you get a LT1 4L60E to go on a LS1, can you use the LT1 Convertor with the 5.3 Flexplate, and a Spacer?
you can use the lt1 4l60e converters and the hughes spacer and 5.3 curved flexplate
I didn't find anything on Summit, anyone found any kind of spacer anywhere?
I found this:
http://cgi.ebay.com/ebaymotors/ws/eB...3841193&rd=1,1
I found this:
http://cgi.ebay.com/ebaymotors/ws/eB...3841193&rd=1,1
