Well I have been using the smoke nipples from Bisson Mufflers in Ontario Canada, however I take a pair of vice grips and close the hole down a little bit so it is a very small hole, it seems to atomize the smoke oil better. I then drill a hole the correct size for an 8/32 thread, thread the hole and then have a 8/32 hex nut silver soldered or brazed to the header pipe over the hole. It gives you added material to thread the nipple into on the header pipe. I then use JB WELD and thread the nipples into the hex nut and this leaves about 1/8 of the smoke nipple protruding into the header pipe. Just be sure that the nipple is NOT pointed towards the exhaust port of your engine, your pump could push smoke oil back into the engine during low RPM's and cause havoc with your engine. I find this makes excellent smoke HOWEVER there is only one draw back to this, it is not an instant off of the smoke. If you shut your pump off at a particular time, you will still get some residual smoke as it empties out of the canister, not a bad thing unless you are timing smoke on and off to music! The key to good smoke is burning the oil at the hottest point, with the smoke nipple in the header pipe, an inch away from the exhaust port, you wont get any hotter than that other than right in the exhaust port!