Considering adding a VH 40 booster to my oval,motorists these days have no consideration for old buses and beetles especially in todays traffic,anybody done this mod considering only boosting front brakes,and possibly then swaping to 58-64 brake setup if still need more stopping power.

Speak to Grumble on here
He does a similar conversion

here ya go

He uses a VH44

http://forums.aussieveedubbers.com/viewtopic.php?tid=72154&page=1#pid677111 

i was going to say Vh44 as they are a little smaller than the vh40 ,early holdens ran vh44 with drum brakes and vh40 with the disk/drum combination

A brake booster isn't going to make your brakes work any better, it just lessens the force needed on the pedal.

For that sort of money if it were me I'd be spending it on upgrading to front discs

I played around with this set and found it created a brake inbalance towards the front and it heated up the drums and they faded sooner, it only reduced the pedal pressure, it would be different if you boosted the back and front

A booster would be great with all wheel disks.

On such a light car it would be a waste of time, on my 60
model its got 300mm vented discs all round with 4 spot calipers, brakes excellently with no booster and minimal pedal pressure