Just something to check; with the engine up to temp, so thermostat is open, open the hood and watch the engine idling... rev up the engine a little and see if the lower radiator hose is collapsing. My 408 Cuda was doing this, and I saw it by accident. The lower radiator hose is the suction...
Start the car when its dead cold and feel with your bare hands at the suspected leak; you will only have a few seconds until its too hot, but it should be enough.
And Remflex gaskets are the only thing that would seal my headers.
You will/should feel a lot of resistance when the oil pressure builds up; also maybe plumb in a mechanical oil pressure gauge, temporarily, to confirm you have good pressure.
I did a Magnum swap on my old Ramcharger, the factory gauge & sender always read low and was a concern. but the...
Remember, back when these cars were built they had bias ply tires which were crap for cornering. Good radial tires with a stiffer sidewall will expose the need for heavier T-bars and sway bars. I dont remember the brand, but I put new T-bars on my Challenger (went from 340 factory engine to...
FYI, if you want to install a factory looking exhaust, the original mufflers were canisters and located b/t the rear axle and the rear valance WITH a bolt on heat shield on the bottom of the trunk floor. The correct exhaust tips attach directly to the muffler output. Fortunately this stuff is...
I believe 1970 California built cars were not available with the dual exhaust through the valance. This could be another "dealer installed" item, but then the tips would be correct. Still a very nice car.
Other than the magnum timing cover not having a fuel pump provision (I have not seen Jegs) all the accessories will bolt up. Some year magnums had a balanced converter, some had a balanced flex plate, if you have a converter with weights on it , I would remove them and get a magnum balanced...