I would only interject that the engines main job is supply power, would it not be best to do it in a lightweight, big torque ,high horse power fashion , then consider cost , sound and price. lastly difficulty of install. I agree with originallity but not to cost of having a car not worth owning. IE.. Blown Pacer.very original but not my taste. with the power options of stroked small blocks and stroked big blocks crate or otherwise it would seem more practicle to use more standard options and modify it rather than using a sqaure block for the round hole approach. It would be nice to see a jet propelled Cobra just not for me to own. good luck on which ever you choose. I am waiting on antigravity motion. no engine needed earth pulling power and lightweight.