The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - 71 GMC Longhorn, compatible engine and transmition

Ozark Tim · 12-06-2018, 05:31 PM

That is a big block and a 400TH from your pics, send me the block numbers (on a pad just behind and above where the water pump mounts to the RHS (pass side) of the block and we can look that up to see if its original to the truck and (most people dont know this) but the original numbers I am asking you to send are on the protecto plate if you have that with the original owners manual so you can confirm
Take your time with it and if you can sort through the issues you will be very glad you kept the original motor
The carb though a Qjet does not appear to be the original but the numbers off the LHS (driver side) would tell us what it is specifically
Cool truck!

12-06-2018, 05:31 PM	#23
Ozark Tim Registered User Join Date: Aug 2004 Location: Oakville, MO Posts: 1,018	Re: 71 GMC Longhorn, compatible engine and transmition That is a big block and a 400TH from your pics, send me the block numbers (on a pad just behind and above where the water pump mounts to the RHS (pass side) of the block and we can look that up to see if its original to the truck and (most people dont know this) but the original numbers I am asking you to send are on the protecto plate if you have that with the original owners manual so you can confirm Take your time with it and if you can sort through the issues you will be very glad you kept the original motor The carb though a Qjet does not appear to be the original but the numbers off the LHS (driver side) would tell us what it is specifically Cool truck!