It is a known fact that most Pinto's came with an over head cam engine. Thus, when you ordered your Pinto (new) with the stripes on the side, you got an engine to match. That being the SOHC 427. But, being that most people bought the Pinto for economy, few ordered the stripes. Thus, yes, these are rare cars.
The 351 version of the Pinto was the economical version of the "side stripe" package. The cost reduction being that this was a OHV engine.
Then of course there in the Pangra. This elongated front end was needs when the inline six (200 and 250) was installed in the Pinto.
Anyway, I hope that clears up the story for you. There is just too much mis-information floating out there about 4 cylinder Pinto's with OHV engines from England and OHC engines from Germany. I mean, come on..., the Pinto is an American car!
Tom
Added 4-26-08 ---- I am of course only poking fun at the "form follows function" concept. Meaning if the car has stripes it HAS to have an engine to make it go faster. If it has an extended front end it HAS to have a longer engine. Such "Idiot logic" as that. :-)