[Halon]

I don't think there is an exact number you can put on a stock tranny and give it a safety stamp of approval.

The age and condition of the tranny are going to be more of a factor than anything else. If you've been slamming gears, your shift forks may be the weak point. The stock center diff is also a weak point if a lot of power has been pushed through it for a long period of time. Gear condition (teeth ready to sheer off).

I personally feel that stock trannies, in GOOD condition, that aren't constantly abused with launches and what-not, are actually fairly strong. The weak point in a stock tranny in good condition, would be your center diff. That is why I chose to go with a stock rebuild, with a 4-Spider diff for my setup. Evo gear sets may handle more, but most of us don't make the kind of power needed for that. At the levels I was making, I never had an issue with gear strength, just stupid synchro's wearing out.

I'm unsure of you power goals, but I would say if you are running sub 400hp levels, a stock tranny in good shape would probably do you fine. Above that, I'd consider getting a 4-spider put in there. If you start reaching 700+ power levels, then you might want to look into stronger gears.

One other tid-bit. The GVR4 first used to be a pretty popular "upgrade" as it was a taller gear. While it may be taller, I've read in quite a few places that the gear itself is actually weaker than the stock DSM 1st gear, and will become the weak point of your tranny. So keep that in mind if you ever are considering the GVR4 1st gear "upgrade".