Ok I have had my 4 wheel disc about 1 yr or so..

78 cutlass up front , 85 camaro out back...

62 corvette MC and a proportion valve from fine lines I believe... but Seems that my rears are not working as much as I would like... Would it be a good idea to remove the (non adj) prop valve and just come out of the MC to the front and rear or shall I opt for a adj valve???

You need some kind of prop valve. With nothing, the rears will lock up well before the fronts in a high speed stop because of the weight transfer.

I use an adjustable with stock disc/drums. Don't see why it wouldn't work for you.

Tim.