Q: I am currently running a 12:4 compression 351W in a Pinto. The engine has World Products Windsor heads, 926 cfm double pumper carburetor on a Victor Jr. intake, 254-degree duration (at .050-inch lift)/.571-inch lift solid cam, and MSD ignition. The transmission is a C-4 with a 4,500 rpm stall converter. I am running 7 psi of fuel pressure through a Holley “blue” electric pump.
The problem is, I have no power past 5,000 rpm. I have tested the fuel pump through the regulator; it flows 90 gph (I run 1/2-inch fuel line). Total timing is set at 36 degrees. The seat pressure on the Crane valve springs is 115 pounds. I have replaced the coil and tested the MSD 6AL box via the “jump” method outlined in the instructions. I also did a compression test, and each cylinder registers 225 pounds.
Where am I losing power? Where do I go next? I’ve run a best of 12.12 at 104 miles-per-hour at the track. I ran 11.60 with a milder 302 in the same car.
A: There are a couple of things you can check. The first is the torque converter; are you sure it’s stalling at 4,500 rpm or is it just rated to that? We’ve seen converters that lock up too soon, and that can keep an engine from making high-rpm power.
The second thing to check for is a restriction in the induction system. Poorly matched intake manifold gaskets or heads that don’t line up with the intake ports on the manifold can cause your lack of high-rpm power.