Well it's the original engine for it. It's got the stamp in the glove box thats says 350 engine. Now I have swapped in a 2 speed rear as I had a h150 single speed 7.20 ratio I belive and it's top speed was like 45mph. Couldn't handle it. Found a t-170 2 speed rear with 6.50/8.25 or so, so I have lower low range and higher high range so I can now pull loads easier and drive 55mph on the highway. But yeah I'll check the c60, I wasn't sure if the medium duty engines were any different but I'll check the c10-30s if I fail on the c60. I wouldn't think they would be but you never know stuff was changing alot at that time. Or I guess they just had alot of different options back then like you said with the straight 6 and the 366 bb. Transmissions as well I have the sm465 4 speed. But I have seen the c60s with 366 and5 speed trans. I'd like to find a 5 speed with a .75 overdrive gear. Give me some speed and mpg savings at a lower rpm instead of 3k rpm at 55-60mph.
