69 C10 12 bolt factory posi questions

[Jinxy81]

I am in the middle of getting the rolling chassis going on my 69 c10 and I wanted to get some input on my factory 12 bolt rear end from the experts.

Based on the numbers on the housing and gear I am pretty positive I have 3.73 gears and a factory posi unit.






I will be using an LS 6.0 engine with a mild cam that will be pushing around 450-470 hp at the crank so maybe 370-380 at the wheels? The gears appear to be in very good shape. We will be pulling out the stock axles and upgrading with new 5 lug axles and axle bearings/seals from Early Classic.

I do have some concerns about the factory plugs that are cracked and weep oil. I know you cannot use just any welder when welding these since pumpkin is cast and the tubes are not. I believe you have to stick weld with nickel rod?







1) Should these cracks in plug be cause for concern or just fill them with some jb weld to stop leaking?

2) With sensible driving not getting on it or peeling out all the time how will this factory unit handle the HP?

3)What all should we look for before using this rear end?

*I have talked to a few local mechanics and they all just say "run it and see how it works before spending money on it" not sure how sound of advice that is.