74 Factory tach cluster to non-tach cluster conversion HELP!!!!

[skevac]

I have a 74 with a factory tach guage cluster in it and was wondering if I took it out and put a factory non-tach cluster in it if all the other guages would still work??? I'm not sure what year the non-tach cluster is but it does still have the mech. oil pressure guage like the tach dash does. I want to sell the truck but am wanting to keep the tach dash so I'm hoping this will work. My guess would be that the wiring harness was the same with or without a tach dash but you never know what they (GM) may have done???? Any and all help would be appreciated.