Water leak

Water goin under dash board not from any of the rubber seals any suggestions where it may coming from its my mgb1979 thanks

Tom's knob?

As Chris suggests, Tom's Knob is a likely suspect. It is mounted to the bottom of the fresh air vent and its job is to prevent anything from entering from underneath the car. Quite often, they become clogged with debris that has fallen through the grill and clogged up the drain. Usually, it can be cleaned out, from the top, with a metal coat hangar. Basically, it's a one way valve. RAY

Thank you

Use a stiff piece of wire to clear the mess, but be warned, it will gush out towards you when it clears.

Lee, that's all part of the initiating process of owning a B. RAY

Check the joint that seats between your wipers and the hood, and between the jets and the hood. Mine were old and cracked and leaked there.
Other problem could be the hood to flange seal (moss 282-815), and the seals on the pedal box cover if you have one; I had water following that path in the past.
Good luck :)-D

What's the best way to seal and can you give me a good name brand I can used and what are the jets are those the water wipers?

I believe the jet assembly for your car would be moss motors part #361-260. I made the gaskets under the jets from a set of plumbing joints I had bought from lowes in the past. But the jet assembly are cheap enough if you want to replace the whole thing.
The seal (pad) that seats between your wiper stem and the body is #282-820.
The seal between the hood and the body are nothing but weather foam roll like you would find at HD or Lowes, it gets squeezed and seals when you close the hood (mossmotors.com part#282-815).
Hope it works for you