What is the stock stall speed on a 95 A4/2.73 Z28?And how high can you go
until you can feel it slippng noticably?

 

I think the stock speed is 1600

 

1600 sounds about right.
Far as how high can you go, if you buy a QUALITY 9.5" converter 3000+ stalls are daily drivable comfortable though a gear swap would help you with drivability of one.
I had for a while a 2800 stall in the Caprice with 2.93s and 27" tires and it was fine even for light towing and even winter use, currently have 3400/3.73s and it drives fine in good weather but the thing makes so much torque it is a PITA in snow.
Wife drives it on occassion and the TB swap caused her more greif than anything else, the 58mm TB allows a lot more air with less pedal movement and the first time she jumped in after I did it she about launched out of the driveway, she had no complaints on the stall though. Heck at idle my car pulls on the brakes more than her stock '03 Impala, I will say my idle is bumped up for the cam but still from memory under 800rpms in gear so it is not high.

 

for a bolt on car only a 3200 would be best.....

 

What cam do you have. That will determine what stall will work best. You want the stall speed to be somewhere around the the begining of the torque band, or at the peak torque for race use. Also, You are definately going to want some steeper gears if you go much above 2500 stall speed.

 

if you really wanna stay cheap, get the gears out of a 4 cyl s10 or sonoma truck and the stall out of a v-6. the stall is a gm spec 3200 and the gears are usually 373 with a 410 option (tow package for the 4 cyl

 

The S-10 converters are more like a 2200 stall and not known for durability.

 

I've had 2 experiences with high stall convertors..1 worked great, the other was a royal PITA. Put a 3k stall in my GN, worked great, could hardly tell there was a higher stall for daily driving, but when brake torquing to build boost off the line it worked great!

Then with the LT1 car, went from the stocker to a high quality billet 3k as my idle vacuum was horrible with the stocker and my cam combo...there was no way I could have used for daily driving...it would literally take 2700 rpm just to get the car to start rolling...cruising at 30mph took about 2800 rpms in 3rd gear!!
Had it restalled to 2400, still took all of that 2400 rpms to get car rolling.
Finally sent the TC back for a refund and installed another, basically a stocker restalled to 2200 and its still quit loose down low for daily driving...just can't figure out why this car drives so differently with even a slightly higher stall...maybe somethign with the tranny rebuild that was done at the same time but I'm just dealing with it now cause I'm sooo tired of working on that car.

 

I've been running a Vigilante (ranging from 2800-3200) for years and experienced none of those problems in any of my 3 motor setups: bolt-ons - cam only - or heads/cam

 

It could be something with the tranny build in my car thats not quit right as well, don't feel like messing with it anymore after 3 convertor swaps and the tranny build didn't cost anything, but back when I was going thru this, it seemed about 50/50 of others having similar issues and all with the Vigilante had no issues like this. My GN has a different brand convertor than my LT1 as well and it had no daily driving issues.

So all I'm really saying is his results may vary by what type of convertor he goes with as all stalls of the same rpm from different manufacturers are not created equal.

 

I had a 2600 Level 10 branded converter before the Edge 2800 and the Level 10 drove like crap and ran hot compared to the higher stall Edge. Both were 9.5" one was just good and one a POS. The Level 10 was a billet cover too, not a cheap converter but just poorly built, they do not build in house it was sourced elsewhere.