In my opinion, Pro Street is basically a term for a street car that "resembles" the Pro Stock class in drag racing.......The basic "traits" of a pro-street car are.....narrowed rearend..tubbed wheel wells in the back...huge "steam-roller" tires.....etc. etc...........It seems to me that the 80's were really the height of the pro-street craze, but I personally think that the look is timeless..... .....As far as motors are concerned, pro-street cars have anything from a mildly built small block all the way up to a radically built big-block with everything in between..now if you intend on putting a pro-stock type motor into a pro-street type car, I'm sure there are plenty of reference photos/diagrams on the net, that would give you your answers.. ...It's pretty much up to you when it comes to a pro-street build....I'm a big pro-street fanatic myself, and I've built different degrees of a "pro-street" car.....or what I would consider to be pro-street anyway.... These are just my opinions, and I'm sure you'll get many, many more.......There's lots of helpful folks on here, with tons of experience..................