on my 912e i am putting in new thermal by pass pipes and original muffler.do i need to put anything on gaskets to muffler heater box and copper o ring from bypass pipes to head?also how best to keep copper o rings in place in head while i attach and tighten bypass pipes.

If you mean adding gasket sealer or something like that, no. To keep the copper rings in the head, put a dab of wheel bearing grease on the ring, that will hold it.

As 914Mels said a little grease helps, I put the gasket in the port and then rotate it as much as possible which can help it hold place.

thanks,do you know what torque nuts to hold bypass pipes to hear require?

i meant to head

If you are using the Bursch bypass pipes, stock heat exchanger and muffler, there are 3 points for gaskets.

1. Head to bypass pipe - These are the oval copper gaskets. #23
2. Bypass pipe to heat exchanger/header - This is an aluminum layered gasket with two ports and gasket #20 in pic. It comes in two styles, one in the pic and one with two holes. 3 Nut/bolts on this
3. Header to Muffler. This is also an aluminum layered gasket, and looks similar in shape to the #20, but is a bit different in shape. It is #12 in the pic. 3 Nut/bolts on this as well.

My original plan had this setup with a new Bursch Muffler and Bypass pipes with original headers. The flanges on my header pipes was pretty messed up and if I used it I was going to use some type of super high heat RTV on both sides of the heat exchanger flanges to ensure a tight seal.

I'm assuming you are installing this while in the car. I would smear a little copper anti seize on the copper gasket to keep it in place while you mount the pipe. You may also want to LIGHTLY run a flat file over the ends of the bypass pipes before hand to ensure they are flat, and some people heat the copper gaskets and then let cool. As for torque, I would go slowly ensuring the bi-pass pipe sits properly in the ports, all bolts snug, then I torqued mine to #20 and after all was installed, heat exchangers, then muffler, I torqued again to 22-24 of 'snug enough' you dont want to overtighten, but like me probably will ;-)

Also, while you do this try not to bend the alt bracket that bolts to the header/muffler bolt, this bracket breaks easily.

Thank you for all the great info