If the engine has iron heads and press-in studs, then no, you don't need guide plates. If the engine has aluminum heads or iron heads with screw-in studs, then guide plates would be appropriate.
a machine that chops peoples heads off
The 302 boss has slightly bigger heads, it comes stock with 351 Cleveland heads.
Depends its might be a bit of confusion there are machine heads (tuners) and a guitar neck.
If the heads don't have push rod guide plates, the rocker arms will set off center just a little. But if they are way off then you must have a bent push rod.
It is a "windsor" (small block) with Cleveland heads (big block).
No, that is a myth
Windsor 351, is a small block. 351 Cleveland, is a big block. The 351M, stands for "modified" and is a windsor (small) block, with Cleveland (big block) heads.
Yes, That is one of the parts that make it a "Boss" type engine.
The guillotine.
take them to a machine shop
It will if you change these parts. You will need a stall converter and you will also HAVE TO CHANGE the valve springs to stop valve spring coil bind. You will also have to have push rod guide plates installed on the heads. GOOD LUCK.