Just wanted to share a couple of things
After having a lot of problems and installing two different engines, I discovered that the engines stalled because there was a aluminum piece lose in the muffler that AE had left there from punching the pressure hole, yeah punching not drilling. Beware, this is not the first time I heard such a piece left in the muffler, if you are having a lot of problems with your engine, uninstall the muffler, separate it from the maninfold and clean it with varsol or acetone, you might discover the little piece in the muffler, if you don't clean it inside with a solvent it is very difficult to detect because it sticks to the oily internal walls. This is only for rear exhaust kits.
The little piece blocks the exhaust exit, that's why the engine flames out mostly on the straights, where there's a lot of exhaust pressure which pushes the debris to the muffler exit, also that is why is hard to restart because there is a lot if oil in the pipe and that is why the engine overheats, because the exhaust gas has a restriction.
After the debris was taken out and the pipe cleaned the car ran almost perfectly with the stock tank without modifications, though there's a little leaner conditon on the straights because of the stock tank desing, I installed a Serpent tank and there are no more problems, the car runs just how it should be.
Hope to help someone with this.