1976 truck built in Flint. Not much info on those engines, but for the most part they were low compression, cast pistons, cast crank, 3/8" rods, probably oval port at that time, quadrajet, low rise intake, usually EGR. The light duty emissions versions had catalytic converters and made about 210 net HP, while heavy duty didn't, and made about 245 net hp. Mostly they've been hot rodded since then, so what you find on the engine will tell you more about it than the numbers.
I was told that GMC's 454 had steel cranks in them, may have still had low compression. This from a knowledgeable engine builder who wanted the engine from my GMC crew cab because it had a steel crank in it. Pat
Reminds me of the question/joke " what's the difference between Chevy and GMC trucks............GMC's had lockwashers".
It is from a GMC, since it has T as the first character of the partial VIN Although I don't believe that rumor.
Jim I was skeptical also but I bought the truck from him, he was a friend of mine and had the engine apart to replace the timing chain. I got it at 290,000 mi and drove it to Flagstaff trailering a 67 chevy for my son who was going to NAU. Sold it at 300,000 and it is still running strong. Pat
I’d never heard that before-regarding GMCs, but if you’re still in touch with the fella, would ask him (for me) why he tore the engine town to replace the timing chain?
My favorite engines. Likely cast crank, 2 bolt, 3/8 rod, under 8:1, oval port, but you never know 50 years after it was built. About the Steel Crank thing, I had a '73 Chev 454 with a factory steel crank, and a '75 GMC 454 with it's factory cast crank. There seems to have been no rhyme or reason. Either way, the old musclecar Hi perf BB guys think all these things are junk read-headed step children, and now the LS guys do too. That's good news for me, keeps prices in line!. A low buck trick to really wake 'em up, is to put a set of '60's oval port closed chamber heads on the smog 454 short block. Gives you about the same good head airflow, but boosts compression to about 9:1. Otherwise, they just need a decent cam (and hensteeth good flat tappet lifters) and a pair of headers. Easy 400HP, and they look good too!
I agree, unless you start pricing out parts for an engine. I was looking into a low CR 454 a few years back and what (after machine shop work) I could screw it together. Dang from gaskets to internal parts, it seemed like everything was at least twice the cost as for a SBC. I didn’t even looking into sourcing heads. GM sure did neuter them after 1970. Had to make Uncle Sam happy.
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