Hello guys. Have not posted in a while. Need help with a project vehicle that i overhauled the trans but i am not doing the install. this is an '06 4l60e that is going behind a 1996 350 motor. torque converter is correct for transmission but will not fit the non ls motor. pilot of torque converter is 1.703 inches but the crankshaft pilot is 1.675 inches. also the flywheel sits deeper int the bell housing so clearance is another issue. Has anybody out there attempted this type of install and if so is there a custom torque converter co that could help with this. Thanks.

 

LS 300MM to older Small block , Yes I have but my solution was not conventiional, At one time we were using a astro van with a 4.3 as a test vehicle and needed this to work out with a test converter to be used over and over, I ground the pilot down till it would fit. I have no idea how much meat was left only that is worked .
That said I have also noted some companies require use of an extention for the pilot to LS on thier converters , So it may be one of those would require no mod as you could just skip the adapter . But I have not tried this.

 

You can have a custom converter made. Likely the best and cheapest solution and you can then also choose the stall speed, etc.
There used to be a GM conversion/spacer kit for this, part # 19154766, but every site now says it is discontinued. Likely because it was too expensive at $450.
Outside of a custom converter, Frank's hack or finding that discontinued GM spacer kit, the only other option would be to convert your LS trans to an LT compatible trans with the necessary input shaft and bell housing.

 

Here is a link to the sticky on convertors and flex-plates.

https://ls1tech.com/forums/automatic...s-spacers.html

I think you need a spacer and a flat flex-plate, but read through the sticky to be sure.

 

No, the "space and flat flex-plate" solution is for bolting a non-LS trans, such as a 4L80E or 700R4, to an LS engine. I am the author of that sticky.
The GM kit I referenced included a "Spacer", but it a spacer to extend the outside of the bell housing, in other words a very large part.

 

I think this is what you might be referencing. this is a copy and paste from the 2026 GM performance catalog

19154766 Transmission Adapter Kit.
Allows installation of Gen III/IV-style 4L60-E/4L65-E transmission onto Gen I and II engines using production-style torque converter; Includes spacer ring, shims, dowels, bolts and flexplate; Works on one-piece rear main seal engines only (e.g. Ram Jet 350)

 

Thanks for all the good info. Sorry for the slow response. Having some health issues that's been having me back and forth with multiple doctor visits. Actually had two appointments just today. We are all hoping for a good outcome. I made some time last week to go the garage where the trans and the engine are to see for myself what was going on. The crankshaft of the 1996 350 motor is very shallow. So the converter for 2006 trans doesn't go in far enough. The original converter which i still had fit fine. So these hubs are all very close in outside diameter with a variance in only the 100 thousand range. The hubs of the two converters vary a lot in length. so if the early converter is the only option, i would have to change the input drum since this converter uses the input shaft with the small pilot tip. no small pilot tip on the 06 trans. For now this all goes on the back burner since I'll be out of commission for at least a month after the 17th of Dec. Thanks again and i will keep you posted.

 

The bell-housing, pump and or pump stator will need changed too All those are different from from an LS 300mm version 4L60E.

 

Thanks Tranzman. Luckily, I have all those parts.