Originally Posted by Camaro 69
That engine should feel right at home in your truck. Although the casting number you gave was used for both cars and trucks, the casting year and the "TSD" code on the front pad tells that it's a 1977 250 h.p. TRUCK engine only.
By the way, 74 was the last year for the 454 Vette, 75 was the last year for the 454 Chevelle, and 72 was the last year for the big block Camaro. (the older Camaros were available with a 396, 402, or 427, not 454).
All correctamundo~! '76 Impala/Caprice was the last of the last to get a big block in a passenger car.
You'll love the torque of the 454,it won't need much of a performance cam just a mild RC cam is all you want for pulling.
I have a 454 in my '78 GMC 3/4 ton 4X4 with a 400 3speed auto trans and 4:56 gears,she pulls like a freight train.
Mine has a mild RV cam (sorry no specs) an Edlebrock performer intake,a big quadrajet carb with electric choke from a Cad 500 engine and a set of headers.
Runs like a top and on regular gas with no issues.
I had a CAT D2 dozer I pulled around on a trailer sometimes,Tractor and trailer together were over 12,000 lbs.
It had no trouble pulling it,in fact I live up a steep winding narrow country road and she pulled it in 2nd gear two wheel drive high range with ease,about 400ft elevation change in two miles.
Make sure you get a 454 flywheel,they are externally balanced for that motor only.
Your small block flywheel will bolt up but you don't want to go there.