The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post

1967GMCC20 · 05-08-2023, 08:54 AM

My 67 Truck 283 turned out to be 307. Few if any 283s had tapered seats. Check head casting number, block casting. REFER to MORTEC casting identification.

#8 the infamous #8.... hello. That's a vacuum leak 9 out of 10 times. Trans line, modulator connected to #8 runner. Modulators can leak putting oil in #8 runner.

05-08-2023, 08:54 AM	#10
1967GMCC20 Registered User Join Date: Apr 2022 Location: Medina, Ohio Posts: 161	Re: Question about spark plugs My 67 Truck 283 turned out to be 307. Few if any 283s had tapered seats. Check head casting number, block casting. REFER to MORTEC casting identification. #8 the infamous #8.... hello. That's a vacuum leak 9 out of 10 times. Trans line, modulator connected to #8 runner. Modulators can leak putting oil in #8 runner. Last edited by 1967GMCC20; 05-08-2023 at 01:46 PM.