Joel , i hoped a second you had the answer :

Plug wires not correct(firing order-1-8-4-2-3-6-5-7..clockwise rotation) but all my books ( racing engine preparation, service manual,car manual ) say : 1-8-4-3-6-5-7-2

also the numbers on the Weiand inlet manifold ............................ WHO's RIGHT ????
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Otay...so I had a brain-fart.
Yes, the power valve will be damaged if there is a backfire thru the carb. The power valve allows more fuel into the system under load. It can be ruptured, and idle fine, but sputter some under acceleration.
And Big-blocks use the same firing order.
The ign. rotor should be pointed at the #1 plug(on the cap) when the #1 cylinder is at TDC, on the compression stroke. It is possible that the dist. is off a tooth, when you put it back in. The rotor will twist as you take the dist. out, and the oil-pump drive rod will twist with it. If you don't turn the pump drive rod back a bit before re-installing the dist., it will not go back in the right place on the cam. Might double-check that.

Thanx. Joel , what i wanted to suppose is this : imagine there is no vacuum connection  and no rev cable on the distributor , than you can install him either way as long as ofcoarse #1 cilinder gets his ingnition on the right time. From that point the distributor rev's 1/2 the numbers as the cranckshaft so every cilinder gets his one on time. No?

So putting the distributor shaft a tooth wrong will give a different setting  of the distributor housing.And there you cannot give a lot because of that rev cable .

Either way it is installed , if you have BTCD with timing light on #1 , it's right , i suppose ???

It's ofcoarse better to mark shaft and housing to replace it in the same position because if to far of , you cannot even start the engine , so no use of timing light to begin with.

Is this right Joel ??

Ok , i see for those power valves...Hope this is the one !

Can't remember if anyone mentioned it but check for cracked distributor cap

Not only the cap.  It could be anywhere in the ignition system.  The coil, coil wire, cap, rotor.

Under increased load and rpm it requires greater KV at the plugs.  This stresses the secondary electrical system.  At that point it could be jumping to a ground instead of firing the plugs.  Look for traces of carbon arcing at the coil tower, cap both inside and out side, on the rotor, etc.

Try mixing up some salt water.  Easier if you heat the water to mix the salt.  Put it in a spray bottle, and spray the ignition system and let it soak a bit.  Then fire the car up and check for arcing.  Salt water is more conductive that regular water.