by now most of us know the 99+00 6.0's have a thinker crank flange than the 4.8/5.3/01+6.0's. my question is what did the factory change to make this fit? chuck at flp said something that i thought was wierd at the time but he wanted to know if i was puting my tranny behind a 6.0 or a 5.3 so he could get the right bell housing on there and i told him it didn't matter but maybe it does, on the 99-00 6.0's anyways.

is that the way they adjusted for the flange is with a little deeper bell housing? can soemone with a 99-00 measure the bell housing on their tranny? i would like to know the distance fromt he mounting surface on the motor to the back of the bell housing.

i am asking because my next project may be a 2500 and i would like to get a older one and save a bunch of cash if i can but i want to know that when i go to toss in a newer motor i know how to handle that thicker crank flange problem. seems to me just measure the housing on a 99/00 and then again on a 01+ and if there is a diference then that is how they made it work and all i will have to do is get a bell housing.

 

the reason they did this was for the 4l80E,at that time that was the only auto behind a 6.0,if you now go to the parts counter and order a 99 6.0 crank, it will be a short crank like all the rest of the Ls1s and they will also sell you a spacer to use along with it.I think the spacer pn is 12563532 and i am guessing it,s about .350 thick

 

BTW i do have a 2k 6.0 take out crank that has less than 500 miles on it, it's a creambuff.

 

are you telling me the 01 an newer 6.0 trucks have a spacer? if i got a 99 2500 and later picked up a built motor from someone without the thick flange all i would have to do is get the spacer?

 

This is what the GM part guy is telling me,it makes sense,i have not seen it with my own eyes.

 

That's correct.

Without the spacer you can use the 4L60E and its torque converters.

With the spacer you can use the 4L80E and its torque converters.

The spacer "kit" comes in handy when mating the LS1 with earlier transmissions!

 

And you will need the matching flexplate,with what parish wants to do he will only need the space,i wonder if you will need longer bolts too?

 

so, to make a 99 - 00 6.0 crank work on a 4l60e, you would need a spacer and the flexplate? did i read that right?

 

no, from what they are saying a 99-00 crank wont work with a 4l60e at all. what they said was to get a 01+ crank to work with a 4l80e i will need a spacer.

i wonder if that spacer is strong? like 1000hp strong? i hope to have some kind of stroker motor with a forged crank and would hate to see some little spacer end up being the weak link.

 

The spacer is a nicely machined piece and locates in the register on the back of the crank. It uses 6 longer bolts to make up the difference.

Maybe the longer bolts would have a slight tendancy to twist at high power levels, but I would think the flexplate itself might be the weak link in this area. The torque converter will always be a nice "cushion" against impact loading from super high horsepower, IMO.