Just what do you have exactly. A 6400 series truck is a 2 ton Chevrolet conventional. 270ci. GMC engines came standard in '47-'51 GMC 3 ton thru 3 1/2 ton trucks. A '47-'53 Chevy COE would have had a 235ci. Chevrolet engine in it. If you're looking for COE parts, is it a Chevrolet COE, or GMC COE. '47-'54 Chevrolet COE's would have been 5100, 5400, or 5700 series trucks. '47-'54 GMC COE's with the small cab, are series 350, 450, & 470. All '47-'54 Chevrolet COE's were rated as 16000lb. 2 ton trucks, unless it's a special ordered 15000lb. 1 1/2 ton truck. '47-'54 GMC 350 series COE's are rated a 2 ton trucks, the 450 series were rated as 3 ton. & the 470 series rated as 3 1/2 ton. There were no 400 series GMC COE 2 1/2 ton trucks. The 400 series trucks that GMC built from '47-'54 were rated as 2 1/2 ton trucks.
