1968 kustom headers and sidepipes

[mar1968]

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?

 

[Tom Bryant]

Yes

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

 

[mar1968]

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

Tom Thanks ever so much. There's a pair of headers on ebay but the numbers on the flange are different than the numbers that the second owner said were on the headers and sidepipes when he acquired the car. The numbers he gave me are similar to the header and pipe unit number (398159..) except he could not make out the last digit on either side. Would you happen to know if the collector pipe assemblies are stamped with their part number as well?

 

[Tom Bryant]

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

 

[mar1968]

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

Tom Do you recall if that pipe was available in different lengths? The pipes on my car were shorter than the Hooker pipes on it now.Second owner said because the noise was right by his head ,it was not the most pleasant driving experience. Of course, not having mufflers in the tubes must have contributed. A while back, someone who had raced a corvette with those pipes contended that when setting up the car on a dyno, the pipe length could be altered to match the power curve. But looking at the the way the pipe connects to the collector, I wonder if that was possible.

 

[Tom Bryant]

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

 

[mar1968]

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 Thanks again for the information. I thought that there had to be some way to modify them as I have seen pictures showing them at various lengths. The 2nd owner described his pipes as having been the same length as those on one of the ZL-1's. Shortening the pipes would have probably prohibited the use of the muffler inserts. Even though the hooker header and side pipes on the car now have muffler inserts, under load it's difficult to even hear your passenger much less the radio (which it doesn't have). Thank you for the much appreciated information. If you happen to know of someone with a set of the Kustom headers and pipes for sale ,I would be a ready buyer. 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

 

[Tom Bryant]

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

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

 

[KO68]

Kustom side pipes

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.

 

[Tom Bryant]

Welcome to the CAC

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.

There can't be too many sets of these around any more. I'd hang on to them too.

Tom