7 inch to 8 inch brake conversion?

[greg78]

Hello, Brand spanking new to the forum so here goes...

I've recently bought a 1957 4 door morris minor and after openning up the front brakes for servicing I measured the drums and noticed they were 8" diameter. I was under the impression that early cars like mine should have had 7" drums front and back is that correct? If so, then I presume someone in the past has converted it/upgraded it! The brake performance is still pretty lousy (I'm used to old cars so not expecting it to perform to modern standards) so my question is this.....when you carry out the 7" to 8" conversion, are there different wheel cylinders that need changing to go with it? I'm thinkng possibly someone has swapped the backplates,shoes and drums but maybe kept the original cylinders - could this account for the poor performance?

Any answers or advise would be greatly appreciated,
thanks