whole kit molded in orange

If the top coat is going to be a light color then use a white primer. If the final color is dark then go with grey or black primer. It makes it easier to get a thinner and even color coat. Also remember that when spraying red or yellow, it's best to undercoat with white. You will get a richer color and use less paint.

I always prime larger parts.  I find for really small parts that I paint with a brush, I can get by without priming.  But lately I have been priming the whole sprues with parts still attached, and touch up sprue attachment areas by brush after cutting them loose.  The larger parts I prime by spray primer after removal.

Always prime.

Hey ! Watch that Auld Phart ting !

 I is one of dem too ! I have seen many in some pretty weird colors or ideas in finishes from years back Like REVELL's metalflake semi-clear bodies . .Prime the whole thing ! .Use a 50-50 primer mix in your a/b and then enjoy . By the way , at 74 I guess I am an Auld Phart ya see ? T.B. 

Thanks for the help! I'll give it a go :D

Best to prime everything. Assemble things like basic engine assembly, seat halves, etc before priming. 

Thank you for the fast reply! Do all the other little parts need to be primered also? Seems it would make them hard to fit/glue ......like i said i never ran across this back in the day.

I prime the body so the paint has something to grab on to  and if the body is going to be painted in a lighter color