I am wanting to join a SM465 with a older bellhousing to a 2000 LS1. The LS1 does not have a bolt hole at the 1:00 position as it was moved to the 12:00 position that my bellhousings do not have the hole at 12:00 but does have the one at 1:00.

I have read we say that they will bolt together just fine which it looks like they will but it combination will be one bolt short.

it is safe to do it this way or should I see if I can find a different bell housing?

Thanks

 

 

I'm running an old school 621 bell with the standard patter, no issues.

 

Thanks I will do some more checking, I did call Novak (they make conversions kits for jeeps) and they said it should not be a problem, but I will keep looking just in case.

 

I cant see the casting number on either bellhousing but they both have a 10 spline output shaft so that indicates they came out of 68-78 4x4's from 1/4 ton to 1-1/2 ton vehicles.

Did you just leave the bolt out of the 12:00 position?

 

I found the fix for this, Novak has a flywheel that is made to bolt to the crank but moves the clutch surface back further so it will work with the older 12" truck clutch properly.

 

Just left it out. Earlier, I did buy a Keisler (now out of business) 621 bell that had the LS pattern. But that had the smaller input bearing retainer hole, I think the SM trans has the larger truck bearing retainer. BTW, you cant tap the LS block to fit the old SBC/BBC bell.

 

The Sachs 1050 does the same thing for about $60.
See this thread on clutch setup.
https://ls1tech.com/forums/conversio...-ls-motor.html

 

Yes the SM465 has the larger bearing, I saw where the bolt at the 1:00 was left out because it would interfere with the cylinder wall .

I will look for a LS1 bellhousing and see if there are any other differences.

 

Thanks Gary, I bookmarked that page so I can hunt thing down

 

I'm installing a Gen IV against a '87 factory hydraulic bellhousing and a sm465. I'm not finished with my setup yet, but here's several notes I've taken from my research and trying parts. Note that this is not completely assembled, and has not been run yet.

Sachs NFW-1050 flywheel surface is 1.5 inches from bellhousing mounting face of LS-series engine.

Gen 1 flywheel surface is 1-5/8 inches from bellhousing mounting face of Gen 1 engine.

Therefore, clutch disk and pressure plate are 1/8 inch closer to engine.

ARP 134-2201 pressure plate bolt kit fits perfectly in the flywheel. Will need to ream three of the bolt holes in the Gen 1 pressure plate.

Stock flexplate is 1/8" thick at mounting flange.(approximate)

NFW-1050 flywheel is 3/8" thick at mounting flange.(approximate)

Therefore, the flywheel bolts should be .25" longer than stock flexplate bolts.(approximate)

It appears that .75" of bolt can safely go in crankshaft.

I would guess that a 1.125"(3/4" crank + 3/8" flywheel flange) bolt would fit, but did not try a bolt this long.

ARP 330-2802 flywheel bolt kit is the exact same length as stock flexplate bolts on the 2010 LS engine. I measured these bolts at .88" under head length – some listings for these bolts say .8" UHL, others say .88" UHL. I bought these bolts but did not use them.

A nearly correct bolt(1.06") is one listed for use with a crankshaft spacer. GM #19257940 ARP #244-2902 However, this bolt has too short of a threaded section. The smooth shank would hit the crank before the bolt seats. I did not buy or use these bolts.

ARP #234-2801 is intended for 6.2 liter lt1 engines. It has an UHL of 1.125" This should theoretically fit, but just barely. It is also all-thread, so the shank is not a factor. I did not buy or use these bolts.

Brother is a GM tech. He looked up the bolt length for a 2005 2500hd truck. This is the proper application for the Sachs nfw1050 flywheel. The manual trans flywheel bolts were listed as .925 UHL, and the auto trans flex plate bolts were listed as 1.102 UHL. This seems backwards, since I'm pretty sure the 1.1 bolt will fit with a 3/8" thick flywheel, but will be too long for a 1/8" flexplate. Regardless, I ordered 6 of the manual trans bolts through GM, because it was convenient and cheap. They are right near .925" UHL. GM part # 11569956 for $2.29 apiece. These bolts came with a light blue substance on the threads. This should provide all the sealing required. I tightened the bolts in three passes: 17, 35, 75 foot pounds per pass. The bolts seem to be very sensitive to overtightening. Use a torque wrench.
The extended hub(higher hub) and the most prominent side of the damper springs go toward the transmission. The flattest side of the disk with the raised spline section goes toward the flywheel.

Reamed three of the bolt holes in the pressure plate with a cordless drill and 25/64" drill bit. Just big enough to allow the new 10x1.5 bolts to slide through.

Removed the original fork pivot ball with a 3/8" allen head drive. Needed impact wrench to dislodge it.

Just to satisfy curiosity, I tried the Gen 1 flywheel on the LS engine. The center bore is exactly the same. The bolt hole pattern is the same diameter, but the individual bolt holes do not line up. The Gen 1 flywheel and crank spaced the bolts in an odd pattern to keep you from installing the flywheel in the wrong orientation. I assume this was for the older externally balanced engines. The LS flywheel and crank use evenly spaced bolts. The gen 1 flywheel sits much closer to the LS block. It will clear the block, but the starter teeth are totally in the wrong place, not to mention that the clutch surface is majorly displaced. A spacer could work, but would not solve the bolt hole problem.

The sbc engine had a dowel in the crank/flywheel connection. The ls engine had an empty hole for a dowel, and the flywheel had a hole as well. I lined up the holes, but did not put anything in them.

On the small block engine, I measured from the slave mount to the fork. I pushed the fork and throwout bearing gently against the pressure plate fingers, and took my measurement from the two highest points on the slave mount and the fork. I got just a hair under 1.75 inches.

I will install the adjustable fork ball(Mr. Gasket 3885G Adjustable Clutch Fork Pivot Ball $31.34) in order to get this same 1.75 inches.

Forgot to mention the Pilot Bearing, this one fits fine -- GM# 12557583 $17.04

 

Thanks for the write up Kipps, that is a big help