More details on what you have will help. is it a F100? I6 or V8? Auto or stick?

Nothing other than the 223 I6 and the Y block V8 will just bolt in, so you'll need some welding and fabricating skills to add side motor mounts. the good news is there are a large number of kits available for this.

You said you want to build a Street Machine. That term means diffrent things to diffrent people. If you mean a custom ride that looks and sounds cool, you could either keep the Y block, or use a 302. 302s are cheap and cheap to dress up with chrome. they are also light weight so easier to work with. The other side of this is if you don't care about the looks so much and just want raw power. The big blocks are heavy and more expensive to modify, but can be built for huge power and torque. The problem there is they can snap axles, pretzle driveshafts, and buckle the body of a unibody