Okay, I rarely utilize forums for these kinds of problems, but this one has been biting me for almost 6 months now, its not a huge problem, but I would really like to resolve it
Bought a 1960 Chevrolet C30 Cab/chassis truck, I'm from Kansas, this truck was ordered by Kansas for hauling trees and was used until the early 90s. It came fully original, lots of paperwork, tag still on the carb, original emergency box with markers etc.
Engine and trans were seized up, sitting for approx 2 years. With some ATF/PB it free'd up the next day, really I probably could have just used a breaker bar it didnt take much to break it free. I put on plug wires, plugs, changed the fluids and it did manage to 'run' and 'drive'
Later found coolant in oil, probably why it sat. only ran a few times prior to finding the coolant.
removed head, replaced head gasket, during which rockers, spring and such looked and moved good, things looked pretty solid and clean, intake, exhuast gaskets, and did a carb rebuild, bought a new heat block under carb. after 2 tries I got everything to seal up. and I have good vacuum pressure 15-20 depending on idle. changed the oil again, no more coolant, all is well.
The 235 can run OK at idle, and run OK up to WOT, but it has to be a reasonably slow transition, or it will hesitate for a second and then start catching up. on a full idle-wot stomp it will either: A: stall, B: hesitate a lot and then catch up, or C: backfire through carb (rare)
I've seen a lot of trouble with the distributors, I did the usual fixes for the OG points dizzy, no change. I converted to a brand new HEI setup. all new plugs and wires again, no difference. Problem occurs no matter where timing is placed.
I looked into the fuel system. I got a brand new fuel pump, and put in brand new rubber in case of pinhole leaks, fuel tank was cleaned out, which really was pretty clean for vintage gas tanks IMO.
I've really dug into the accelerator pump on the carb, I put in a new one from the rebuild kit, it seemed a little too tight, I tried switching it back to the OG, no difference. everything else on the carb looks good, I blew it out with compressor. everything that should move freely is moving. doubled checked again for vacuum leaks even though pressure is good, couldnt find anything.
Tune wise, it seems happiest/fastest/smoothest with a lot of timing, fast idle, and mixture backed out a ways. anything outside of that combination it gets boggy or rough
You can drive the truck around fairly well. it cruises well, the power feels accurate. You can downshift without issues, have plenty of power. it just has a really hard time with the upshifts. I do have a higher gear ratio out back than OG but then, it has the issue while parked also. I'm not a stovebolt expert but it sure feels like I'm going to be by the time I get this thing running better.
