Mating an LS engine to Old SBC transmission
Now that I have successfully brought back a 5.3 LS from the dead, its time to prepare for installation. For those of you who've been following me, I've been prepping my first LS install into an OBS (73-87) chevy truck. I looking to replace the tired 350 for something easier to start when its -40 below, and net some fuel mileage in the process.
My setup is an old school sm465 trans, which I plan on reusing for a multitude of reasons. In order to make this work, I need a custom flywheel setup of some sort to make up the .400 difference due to the crank recess that the LS engines have.
My first venture into this, I found Mcleod makes a custom flywheel for a pricey $430 + shipping. This would allow me to use my old school clutch, however I would have to downgrade from a 12" to an 11".
Advance adapters also makes a kit for a little over $600, flywheel, bolts, clutch and everything. However with shipping, I'll be close to $900. Again, very steep.
Further research lead me to LSC performance, who makes the same thing, for $275. Unsure if it will allow a 12" clutch or not, but its half the price, and is .400 thicker for these conversions. I was sure I was going this way until I found another thread on LS1 tech.
It states that if I use a flywheel from a 2006 4.8 or 6.0, it will allow mating of a 12" clutch. It is .400 thick from GM, and the mounting holes from the old school pressure plate line up. The flywheel is drilled for metric bolts (M10), and the pressure plate mounting holes only have to be reamed out slightly to make it work. This flywheel (sachs NFW1050), commonly goes for about $60. Stock replacment 12" clutch could still be used, and all I would need is an extended pilot bushing.
Has anyone else had any experience doing this? I'm really keen on keeping the 12" clutch, since its a heavy truck that does a lot of towing, so clamping force is key. While I don't want to cheap out on parts, I have to spend enough in other areas, saving a couple hundred from a custom flywheel would be benefical. Suggestions?
