Ok to heat and bend a pitman arm?

If you must raise or lower the tie-rod end of the pitman arm, do what the factory service manual tells you to do and add/subtract body shims between the steering gearbox and the K-member. Bear in mind, whatever you do to the pitman arm, you must also do to the idler arm. If you raise both, this will leave you with longer and steeper outer tie-rod segments. This WILL cause the wheels to toe out when you hit bumps, causing bump steer. Generally not a desirable handling trait. However, there is something that may save your bacon a little. If you set the front ride height lower than factory specs, the outer tie rod will be higher relative to the inner the inner at your static ride height, and possibly closer to the factory relationship (lowering and headers usually don't work too well together though). You can also add shims between the motor mounts and the K-member if you need to tweak the final engine position, but this might be going in the opposite direction from what you need. Oh and as long as you use a piece of iron pipe to make a nice radiused dimple, I wouldn't worry about denting the tubes too much. If they run under the steering linkage, you will dent them pretty good with the street.