Even though the BB was not used in 4wd's from 1968 forward all frames 2wd or 4wd had a notch cut out of drivers side frame rail on top for clearance of BB exhaust, your 67 frame will not have this and unless you buy the tubes and custom make your headers or luckily find a set that can clear frame as it is you will need to notch the frame in this location. Since they were never any made specifically for these trucks with 4wd and BB I would look at a set of shorty headers with a rear exit as they should best suit your needs.
GMCPaul
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67 LWB GMC SuperCustom Fleetside
67 LWB GMC Stepside
67 SWB GMC Stepside
67 SWB GMC Fleetside
67 SWB Chevy CST Fleetside
67 LWB Chevy CST Fleet
67 SWB Chevy Stepside
67 LWB Chevy Stepside
68 2wd Chevy 1/2 t. Panel
68 Chevy Panel 1/2Ton 4X4
68 LWB Chevy Fleet 4X4
69 SWB Chevy Stepside
71 GMC Suburban 402/400
72 LWB Chevy Camper Special
72 LWB Chevy Camper Special
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