they both advertise 30% increased holding strength, so i kinda think SLP just sells the LT4 pp

 

Yes. SLP's is the LT4 only with holes drilled.

 

I ordered a slp PP because i had read so many times on this board that the SLP PP is the LT4. I pulled my motor and was looking at the pressure plate in the car and the part number is the same on the old PP as the SLP PP and that number is 382109-DO that is the only number i can find. I have looked on brents page and my SLP doesn't have the square throw out bearing but it does have the flat fingers on it like the LT4. The SLP has the round throwout bearing but doesn't have the ridges on the fingers like brents stock LT1 pp. My car had a clutch put in it by a previous owner but the car didn't have a single mod done to it so i doubt the clutch and pressure are anything but stock. I haven't removed them from the old motor yet to see if by chance the old PP is a SLP. The part number on both my SLP and my old PP aren't the same part number i see for stock LT1's which is 10207027. The part number i did find didn't match up with the LT4 set up either. To everyone that says the SLP is the same as the LT4 what are you basing this on? Anyone have any proof if this isn't a LT4 i am going to have to rush ship a LT4 PP so i can have it this week for balancing.