I have a 1978 GMC C15 with a .030 over 292 and a 700R4 in it. The engine has a stage 1 Lowe roller cam in it. The head is big valve, lump ported, 59cc chambers with 30cc dished pistons. Clifford intake with a Holley 390. 700R4 trans is a heavy duty build with a B&M shift controller and a 2200 converter. Yukon 3.73 posi rear. Pertronix ignition. 255/65/16 wheels. Electric fans and Vintage Air AC. On a wheel dyno it hit 196HP and 248FT at the rear wheels at 4200RPM. Peak torque was 260 at 3800 RPM. It runs very well, very strong. It is my daily driver and is driven to work and used every day in a regular truck fashion. However, I am doubting my choice in converter. The gas mileage is abysmal, 10.5MPG at best. And as I spend the large majority of my drive time at low RPM, generally below 2000RPM, it always feels like I am just spinning the converter uselessly. When I floor it off the line or when passing and the cam comes on at about 2500 it pulls seriously hard but I rarely do that. 99% of my time is just slow driving with traffic to work or around town. I'm thinking of dropping to an 1800 converter. Anyone have any suggestions or thoughts on this? On what you think might be the best converter considering my use?
Last edited by sodell; 08/09/21 11:34 AM.
