Hi all New guy here I have a '59 GMC two ton and I’m thinking of a 350 engine swap. The existing engine is questionable, the accessories are original by the look of the caked on dirt and oil mud stuck to everything, and the intake and exhaust manifolds are broken but surprisingly the engine ran. Was a farm truck from Saskatchewan and serviced well I assume but finding new parts isn’t practical for me I assume that means new motor mounts and perhaps a new cross member Any information on what is required would be greatly appreciated. Thanks
Nice looking truck ,before you give up on the origional heartbeat I would check out its condition ,there are lots of parts still out there especially in your area .Depending what you want to do with the truck the rear axle ratio may be more of a concern if you want to hit the highway.
I've been talking with Don outside of this forum. Additional information that may be pertinent is ...
Canadian GMC, so the engine is a Chevy 261. Transmission is a SM-420.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12 '52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
I am also assuming your truck has a 6 in it and being from Alberta if there is a six it would be either a 235/or 261 ,The American trucks would have the harder to get parts for gmc engines as they were gmc engines 270 or v8 . You can check what engine you have by casting numbers and throw a few pictures on here for us to see .
If you decide to go ahead with the V8 conversion, it would probably be a wiser choice to find a big block engine- - - -a 366, 396, 427, or 454 instead of a 350. Small block engines can produce a lot of horsepower, but they do it at RPM ranges that aren't truck-friendly. The big block engines have more low end torque, and the "tall block" 366 and 427 engines were designed for truck use from the beginning. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
If it's got the short gears that these rigs always had-potentially 7.10:1-then a small block will be better, because it is more a high RPM engine. If it's got the usual T-150 two speed with high of 6.40:1 then actually a 327 or 350 will be fine. Also, these trucks came stock with a 283 option, so the stuff to fit it in the frame will be somewhat easy to find, at least in this forum.
I wish it were still possible to find the taller 5.83:1 gears GM offered for that differential, because then that would mean lower RPM at modern (more than 54mph) cruising speeds.
If I had a million dollars, I'd pay Georgia Gear to produce a run of taller gears for our old two tons.
