The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - 427 or 454: how can you spot the difference?

dyno · 03-08-2010, 10:53 PM

Hi,

I just bought a 1973 K20 4x4 flatbed with a big block. The guy says it's a 427 but not 100% sure. Could be a 454. How can you tell the difference? I can't see the block casting number. It's too close to the firewall.

Thanks,

dyno

03-08-2010, 10:53 PM	#1
dyno Registered User Join Date: Sep 2008 Location: Middleton, Idaho Posts: 352	427 or 454: how can you spot the difference? Hi, I just bought a 1973 K20 4x4 flatbed with a big block. The guy says it's a 427 but not 100% sure. Could be a 454. How can you tell the difference? I can't see the block casting number. It's too close to the firewall. Thanks, dyno __________________ "Built- not bought" 1958 GMC 150 4x4 in progress 1980 K20- Restored 1985 K3500 Flatbed 58 GMC 4x4 build thread: http://http://67-72chevytrucks.com/vboard/showthread.php?t=557675