Additonal Speakers ?

[Ironhorse]

Thia is not quite truck related but it is audio relative so here goes. Another one of my projects is a '71 Chevelle 2 dr. Have gotten quite a bit done with the mechanical end and have been driving it from time to time. Need to get some tunes going so here is the problem.

The after market head unit was cut into the dash, which is plastic, ABS, or ...? and is a single DIN sized unit. Since the dash was already cut that took that "cut or don't cut" out of the equation. I was able to find a Sony, 200 watt am/fm/cd/cassette which is also single din with removeable faceplate. Problem is the back deck of the Chevelle has two holes cut for 6x9 speakers and two holes cut for 6" round speakers. (????) I have a pair of Pioneer 6x9 150 watt tri-axials on hand and also a pair of 6" round Pioneer 180 watt co-axials. The rear shelf or back deck holes look like they were cut with a small hatchet or worse. I can clean them up somewhat with a grinder / file but will I better my self by adding both sets of speakers together or just go with the 6x0's and "patch" the 6" round holes some way?

If I run all four speakers together what is the best way to wire them or how do I go about that? Bear in mind I'm not a real audio guru at all, I know enough maybe to be dangerous at it. LOL Any replies and tips are much appreciated.