mar1968
New member
Would anyone know what the correct part numbers are for the optional big block corvette headers and sidepipes made by Kustom but sold by chevrolet?
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Header and pipe unit LH 3981591
Header and pipe unit RH 3981592
Header only LH 3960709
Header only RH 3960710
Collector pipe assy LH (use with 3981591)3960713
Collector pipe assy RH (use with 3981592) 3960714
Muffler (2 req.) 3977899 (fits inside collector pipes)
Gasket, header to block 3960712
Bolt, header 3960711
Source: Chevrolet Heavy Duty Parts List 12/7/1973
No, I don't know if the pipe was stamped. The same pipes were used on both the big block and small block sets. It could be that the part number changed from the time that the headers were first made available and the time that my list was printed in Dec 1973. Any change in design would have caused a new part number to be assigned to the part. I seem to remember that the early ones had some fitment issues that were addressed later. Can't say absolutely. It's been a long time. Also many times a part identification number cast into or stamped into a part will be different than the part number. Sometimes only off by a digit or two.
Tom
They were all shipped full length. Like you said, they would alter them to match the power curve of the engine. I would bet that they used different lengths on the same car on different tracks. I've seen pictures of them as short as about 18" and some in the mid rocker panel area. Those would be right at your ears. Longer should make more low end torque by lowering the torque curve and shorter would make more high end power for the big tracks like Daytona.
My Hooker side pipes on my '67 427 coupe made the radio useless at about 30 mph. I could imagine no mufflers inserted and shorter pipes. You would need ear plugs for sure.
Tom
Tom I do have another question I'd like to run by you. Do you have any information about the wo (work orders) used on some cars designated for research and development?
Thanks
I have a nice used set. Not really for sale but have the correct part #s. on the headers. No part #s on the pipes. I have some pics if u r interested.No I don't. You might try searching the Restorer archives or the Tech Board archives on the NCRS site. At some time there has probably been an article or thread on this or a related subject.
Tom
I have a nice used set. Not really for sale but have the correct part #s. on the headers. No part #s on the pipes. I have some pics if u r interested.