Improper fit with hedman headers

[Jebadiah]

I'm working on a 90 c1500 with a 350 and 700r4. I just purchased and started installing hedman part number 69440 headers. Driver side bolted up ok but it's stepped out so far it's basically touching the frame. Ok I figured I'll just dent the pipe there and all will be good. Moving on to the passenger side. It's so close it almost fits. But not quite. I can get some of the bolts started but the header is touching the frame on that side too. Some of the bolts can't be started because the header is angled in because of frame contact. Do I have the wrong headers? Are they made wrong? I called hedman and they gave me a different part number telling me that some 88-91 trucks have an engine offset toward the passenger side and some are center. Does this sound right?

 

[Drunkcanuk]

I'm working on a 90 c1500 with a 350 and 700r4. I just purchased and started installing hedman part number 69440 headers. Driver side bolted up ok but it's stepped out so far it's basically touching the frame. Ok I figured I'll just dent the pipe there and all will be good. Moving on to the passenger side. It's so close it almost fits. But not quite. I can get some of the bolts started but the header is touching the frame on that side too. Some of the bolts can't be started because the header is angled in because of frame contact. Do I have the wrong headers? Are they made wrong? I called hedman and they gave me a different part number telling me that some 88-91 trucks have an engine offset toward the passenger side and some are center. Does this sound right?

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found this little note on summits site. So probably something yo the engine being offset.
Id say break out a tape measure and see what the measurements are.

 

[RoyBob]

I'm working on a 90 c1500 with a 350 and 700r4. I just purchased and started installing hedman part number 69440 headers. Driver side bolted up ok but it's stepped out so far it's basically touching the frame. Ok I figured I'll just dent the pipe there and all will be good. Moving on to the passenger side. It's so close it almost fits. But not quite. I can get some of the bolts started but the header is touching the frame on that side too. Some of the bolts can't be started because the header is angled in because of frame contact. Do I have the wrong headers? Are they made wrong? I called hedman and they gave me a different part number telling me that some 88-91 trucks have an engine offset toward the passenger side and some are center. Does this sound right?

Had same issue with my 89 Found some at Jegs They fit perfect they are mid length Here is the part number For some reason People says what fits but NEVER PUT A PART Number

Part Number: 555-300550​

 

[Jebadiah]

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found this little note on summits site. So probably something yo the engine being offset.
Id say break out a tape measure and see what the measurements are.

I measured the offset on 4 different gmt400 trucks and they are all the same. I think the offset difference is between the squarebody carry overs and the 400s. The best explanation I can come up with is the headers are made wrong. What other longtube headers will fit? The jegs brand appear to be made by hedman as well.

 

[Drunkcanuk]

I measured the offset on 4 different gmt400 trucks and they are all the same. I think the offset difference is between the squarebody carry overs and the 400s. The best explanation I can come up with is the headers are made wrong. What other longtube headers will fit? The jegs brand appear to be made by hedman as well.

I have Hedmans on my 91, put them.on 20yrs ago, no issues other than having to weld a 0² bung in. I don't have a part number, but can look when I'm home on the weekend.
Hooker makes headers for them still probably.

 

[GrimsterGMC]

I have the Hedman 69840 headers on my 1988 K1500 and they are a perfect fit. The only difference between mine and yours is that mine are thicker walled and are ceramic coated.

 

[Scooterwrench]

You may have worn out sagging motor mounts letting the engine sit down to deep.

 

[GoToGuy]

Have you checked your engine mounts? If the rubber is degraded or there sagging this can also fit issues. Just something to consider.

 

[GoToGuy]

Oh, so close.

 

[Scooterwrench]

Oh, so close.

Ha-ha,I win!!!