Ok i have to admit I listen to a lot of diffrent types of music but when it comes to 70's music I am picky. I was born in 75 so I missed this decade pretty much.
As I got older and my Dad rubbed of on me i did get into some 70's music and do still listen to some bands but in the "Christian" side of that era I know very little about it so recommend some bands to me, I have a slow dial up so I don't get to listen to Tri Rock a lot so if I put in a 70's request make it worth it.
I like from the 70's
Kiss
Styx
Van Halen
ELO
Boston
Black Sabbath
Deep Purple
Rainbow
Led Zepplin

I am familiar with Rez they are good but not quite my preference.
So educate me

Uh....you just listed some of the greatest metal ever written :/ Hard to compare too, sadly...

The only band I can think of during that time was Messiah Prophet, but they were more Acid Rock. I actually can't think of anything close to Eddy Van Halen...if there was I'd probably be listening to it ;)

I have heard of messiah Prophet I used to have master of the metal, I wore it out I saw that they had a couple albums before that one they were good.

I forgot to list a couple other bands i liked too

Scorpions
George Thourogood I think he was in that era
Blackfoote
Meatloaf
some Alman Brothers stuff

Ok... what I suggest is listen in to the 70's show Fri 4pm, sat noon and Sun 2pm WEST COAST Time, there you can listen to it all... but let me warn you... lot of it is cheezy... but I have learned to like it, cause it is classic and RARE!!! They didn't have loads of money neither they had the churches to back them up... they were mostly alone.

Look for bands like -

Glass Harp
Fraction
Larry Norman
Bang
Sir Lord Baltimore
Rez Band
Degarmo & Key
Azitis
Joshua
The Exkursions
All Saved Freak Band
Austin Roberts
Damascus
DArrell Mandsfield
Ed Raetzloff
Earthen Vessels
etc...