Two Questions re: exhaust & CV axle (3S-FE)

[TBayToyotaBoy]

Ladies and germs, I have managed to encounter not one but two conundrums in one shot (I rarely run into any new problems that I haven't seen before).

Qualm #1 : My downpipe-to-cat gasket keeps blowing, causing chuffing. I've replaced it twice, once torquing the flange bolts loosely, and once quite tight. Does anyone know what the actual torque specs are on these exhaust flange bolts/nuts?

And Query #2 : My 4-cyl is a 1991, Japanese production unit, and it has the annoying (and ever-so-rare) clip-in style driveaxles. I cannot find a replacement anywhere in town (nor do I want to buy it new when I have limitless free "bolt-on" CV axles at my disposal). If I bring my clip-in axle and a bolt-on axle to my friendly neighbourhood machine shop and ask them to press the inner shaft of my 91 onto the outer shaft of a bolt-on, will they be compatible? (Less long-winded way of asking: Other than the clip/bolt-in feature, are the axles identicle?)

A million thanks to anyone who's had to deal with such issues, and who can help me out.

[Doctor J]

The torque for 10mm (M10x1.25 mm) diameter exhaust studs is 30 to 35 lbs-foot [underhood converter]; or 20 lbs-ft for M8x1.25 mm bolts used for underbody converter; the gaskets are made from paper-metal tape about 7 mm wide;
I reused my muffler gasket by sealing it with hi-temp industrial black sealant;
The flange shafts for bolt-on axles should fit into the holes for press-in axles; the center bearing bracket I.D. should be the same.

[TBayToyotaBoy]

Thank you most kindly for your help, it is truly appreciated.

[toyomoho]

www.rockauto.com has rebuilt clip-ins.

[TBayToyotaBoy]

Yeah, they were the first place I checked when I decided to sell the car. But because I'm trying to minimize costs for the sale, I'd like to avoid spending the cash on a new or a reman unit. I want to try using one of my free scrap yard axles (even though I don't work there anymore I still get free stuff)...