I agree with Wittsend , a Straight six is very wrong for any pinto unless you put a tube frame and use it a a drag car , my famous words is don’t cut the car , it will be forever loss if you give up and only good for scrap , I have seen it happen way to many times , but here we can give you some other way to fill the bill for lust for horsepower , the tried and true 5.0 transplant worked well when thought out , but now parts to install it are now rare and short of the gold standard, next on the list is turbo 2.3 , yep easy to do and kind of keeps the handling of the car much better , it to is becoming rare , I have been watching this happen over the years , I have a Pinto cruserwagon that I will have to swap in something, the V6 that was in it was used to fix and finish my V6 pinto sedan , and I have been looking to install an engine that is a bolt in that brings Power and good MPG and can still buy parts , and my choice is the 3.7 V6 out of the mustang , 305 hp stock , 30 plus’s mpg , it look wide but that’s the valve covers , in the back across the engine it’s 21” wide , same long , will have to mod the oil pan and come up with a shorter intake , This is my next project (I retire in November) but figuring out how to make it fit well will come in the next few months, if it doesn’t then in goes the Tesla drive train , then a four wheel drive 10 second Cruse wagon , ( plan “B”) just in case plan “A” does not fit , have a good one and everyone try to come up with a bolt in , later