Doug's Headers 303Y Fitment Issue - '87 1-Ton CC
 

So I'm working on the exhaust and the driver side header does not fit. Comparing to my Dad's '83 K20 I am seeing the 3/4-ton frame is different than the 1-ton frame and the design of the headers has changed slightly.

- On my Dad's K20, the frame rail narrows up by the #1 primary whereas the 1-ton frame stays wide all the way back, only narrowing just after the #7 cylinder.

- the #3 primary on my Dad's K20 turns rearward and actually curves back toward the engine block sitting more on top of the #5 primary before it turns down to Y with the #7 primary. On my headers, the #3 primary turns straight back and carets next to the #5 primary and then turns down and cuts in to the engine to clear the frame.

The difference in the new vs. old header design would not make a difference on a 1/2 or 3/4-ton but it seems the 1-ton frame is the issue!

Can anyone else confirm this issue or has anyone installed the D303Y on a 1-ton?
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Re: Doug's Headers 303Y Fitment Issue - '87 1-Ton CC
 

Okay, well I found out two things...

1. Bad motor mounts will cause the headers to have poor fitment...

http://youtu.be/DmBtoqfIx_g

2. The 1-ton frame is different than the 1/2 & 3/4-ton frames. The #3 primary is still making contact with the frame, I am going to make some room tomorrow!
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Re: Doug's Headers 303Y Fitment Issue - '87 1-Ton CC
 

That p/n is motorhome application?
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Re: Doug's Headers 303Y Fitment Issue - '87 1-Ton CC
 

No, it's for 69-91 Chevy/GMC 4x4 trucks 396-454 and specifically noted for my '87 V30 according to Doug's website, Summit's website and Doug's Tech Support. My dad has them on his truck and they clear fine. It's a combo of the redesign of the #3 primary and the 1-ton frame...
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Re: Doug's Headers 303Y Fitment Issue - '87 1-Ton CC
 

http://www.ifitsgotwheels.com/pictur...g?m=1344662812

i had to clearance my 1 ton frame for the old headers i was using.

no idea on brand, picture is more to show what i did to make them fit..

Re: Doug's Headers 303Y Fitment Issue - '87 1-Ton CC
 

Okay, the passenger side on mine have miles of clearance, and I don't have to remove nearly that much material on my driver side, possibly 1/4" or so at most.

It just bothers me that as much as the Doug's headers are, they would have figured this out. I'll call tech support on the morning and see what they have to say. I know the truck is a factory 454 truck so it must have the proper frame stands and mounts so that shouldn't be the issue...
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