Will M6 work behind a LQ4 crankshaft?

68 SS · 03-14-2009, 02:45 AM

I am being told the LQ4 crankshaft flange is .400 longer and the M6 will not work with the stock LQ4 crank is this true? I thought all the 6.0 cast cranks were the same other than the bob weight?

Steve Bryant · 03-14-2009, 01:33 PM

The flange on 1999/2000 LQ4 cranks are longer than 4.8/5.3/5.7 cranks. 2001 and after LQ4 crank flangesare the same lenght as are all other Gen III & Gen IV small block cranks.

Steve

JUNK · 03-14-2009, 06:35 PM

It's true, the starter bendix will miss the flywheel when u hit the key. It will work on auto by using the truck flywheel. I found this out back in '00

Eikon · 03-15-2009, 10:25 PM

Quote:

Originally Posted by JUNK

It's true, the starter bendix will miss the flywheel when u hit the key. It will work on auto by using the truck flywheel. I found this out back in '00

Just so I'm sure I'm understanding this correctly...

If I have a 99 or 2000 LQ4 motor, I will not be able to mate it to a T56 6 spd trans unless I use a truck auto trans flywheel?

I don't suppose they make any lightweight flywheels for the auto truck?

This sucks! Maybe I'll have to rebuild the motor and get a crankshaft...

68 SS · 03-16-2009, 03:01 AM

Yep the more I searched the more I figured this one out you will either have to swap cranks or use the 4l80 slushbox out of the truck but the M6 will not work behind the early 6.0 crankshaft and the truck flywheel will not work with the M6...yes it sucks! Just one more reason to build a stroker...for what it is worth a new LS2 crank from GM is 360.00 and will fix your problem but you will have to balance your rotating assy.