classicdmax 190 #1 Posted August 24, 2016 ive seen alot of stack questions on this forum and elsewhere on the web...sorry to do this again. id like to fab my own using polish stainless tubing which i can find at a fairly reasonable price. my question is concerning tubing diameter, and is a muffler needed for back pressure? 1" seams rather small, and not sure if 1-1/2" will do the trick thanks for any input offered i have a 73 16h auto, kohler k341 Share this post Link to post Share on other sites
Ed Kennell 35,146 #2 Posted August 24, 2016 In most cases the backpressure is only a good thing at low RPM where the vacuum created behind each slug of exhaust can actually help extract the next slug increasing the low end torque. With these governed engines that are normally operated near WOT, there is a steady stream of exhaust therefore back pressure is a bad thing robbing HP. Go big. 3 Share this post Link to post Share on other sites
Wildhorse 298 #3 Posted August 24, 2016 1 hour ago, classicdmax said: ive seen alot of stack questions on this forum and elsewhere on the web...sorry to do this again. id like to fab my own using polish stainless tubing which i can find at a fairly reasonable price. my question is concerning tubing diameter, and is a muffler needed for back pressure? 1" seams rather small, and not sure if 1-1/2" will do the trick thanks for any input offered i have a 73 16h auto, kohler k341 I have a 2 1/2" stack on my 58 and 65 looks good and not over the top plus sounds nice. 1 1/2" looked too small in my opinion but that's personal preference. Whatever looks good to you is the right one. 1 Share this post Link to post Share on other sites
Wildside 195 #4 Posted August 24, 2016 1'' pipes, stainless and sound Awsome!!! 2 Share this post Link to post Share on other sites
classicdmax 190 #5 Posted August 24, 2016 8 hours ago, Wildhorse said: I have a 2 1/2" stack on my 58 and 65 looks good and not over the top plus sounds nice. 1 1/2" looked too small in my opinion but that's personal preference. Whatever looks good to you is the right one. I like the sound of using 2-1/2", any pics? Share this post Link to post Share on other sites
82Caddy 851 #6 Posted August 24, 2016 I have stacks like these: 1" NPT threads. Sounds pretty good. I also have the same stack on a k341 and it sounds awesome. Only difference is it has a 1.5" pipe on the inlet. 3 Share this post Link to post Share on other sites
953 nut 51,018 #7 Posted August 24, 2016 I used a Harley Davidson muffler, Just used a 1" to 1 1/4" bell coupling and it slips right over the 1 1/4" pipe. Sounds soooooo goooood! 5 Share this post Link to post Share on other sites
userj8670 68 #8 Posted August 25, 2016 21 hours ago, Wildside said: 1'' pipes, stainless and sound Awsome!!! Video please! Share this post Link to post Share on other sites
Wildside 195 #9 Posted August 25, 2016 Trying to upload video. 1 Share this post Link to post Share on other sites
userj8670 68 #10 Posted August 26, 2016 On Thursday, August 25, 2016 at 5:48 PM, Wildside said: Trying to upload video. Any luck? Share this post Link to post Share on other sites
classicdmax 190 #11 Posted August 27, 2016 I found 304 stainless threaded fittings on the web, thinking I might try to weld a piece of 2" polished stainless pipe to the 90deg fitting. next question, any magic tricks out there to remove the existing threaded coupler from the head. Right now it seams to be pretty rusted in place. I've been spraying down with pb blaster the last couple days....am just afraid to throw a wrench on there and break break the head Share this post Link to post Share on other sites
Ed Kennell 35,146 #12 Posted August 27, 2016 Yeah, don't break the block. Cut the nipple off close to the block, then use a sawsall to cut a slot in the inside of the nipple. Then peel the corners in with a narrow chisel. Use a pliers to turn it out. Retap to clean up the threads. 1 Share this post Link to post Share on other sites
userj8670 68 #14 Posted August 27, 2016 20 minutes ago, Wildside said: Thank you for posting! Love it!! Share this post Link to post Share on other sites
classicdmax 190 #15 Posted August 27, 2016 8 hours ago, Ed Kennell said: Yeah, don't break the block. Cut the nipple off close to the block, then use a sawsall to cut a slot in the inside of the nipple. Then peel the corners in with a narrow chisel. Use a pliers to turn it out. Retap to clean up the threads. What about getting and shavings/pieces of metal inside engine Share this post Link to post Share on other sites
Ed Kennell 35,146 #16 Posted August 27, 2016 This should not be a problem on the exhaust side of the engine. You can use a vacuum and a magnet to clean out any metal chips. Don't blow the chips in with air. Share this post Link to post Share on other sites
Wildhorse 298 #17 Posted August 27, 2016 On August 24, 2016 at 6:19 AM, classicdmax said: I like the sound of using 2-1/2", any pics? Here's a pic of the 655 with 2 1/2". It's a Gibson tip Share this post Link to post Share on other sites