distributor cap differance

[220bhp]

I am about to fit my rebuilt engine, and to be safe I bought a new distributor cap,from GSF.
It came in a box marked intermotor, there is no part no on the cap but the box is marked with to numbers,45910, and 5 012225 125111.
I compaired it with the old one from the blown engine and it is different.Firstly the distance from the base of the cap to where the clips locate is 2 or 3 mm longer on the new cap,secondly the electrodes are arranged differently,on the new cap they come straight out from the base of the cap and have no plastic around them.
On the old cap the brass electrodes are incased in plastic on the back.
Just to make it even more confusing,I have a third cap,which came with the doner engine,and it is a Beru,the number on it is,BERU Germany VK 354 IN.
This is also different,the distance from the base to where the clip locates is even less than the other two by about 2 to 3 mm,conciderably less than the new one.
We all know about the possible spark hope issue, and the use of the narrow tipped rotor,but what about this differance in the dizzy caps, which is the right one to use and what was original.
I have new magnicor leads,and a new dizzy with bronze gear, but which cap do I use

[UrS4boy]

Proper KV, NG, NM, 7A and 3B distributor cap is 034905207B if that helps any.

[220bhp]

Proper KV, NG, NM, 7A and 3B distributor cap is 034905207B if that helps any.

Thanks for that,much appreceated,but the interesting thing is the variation between the caps.
We buy these parts from the suppliers, assuming they are the right parts,but we also read on the forum that the rotor arm part number is wrong,and that we should use the narrow tip.
That leads me to think,what about the dizzy cap.
How many people are running there cars on different distributor caps,and which is the right one,bearing in mind that Audi at the time did not think about more power for the 3b,because it was concentrating it efforts on the aby.

[220bhp]

I put this part number 034905207b, into a search engine,and as urs4 boy has confermed is the correct part no for the 3b,and I agree that is the right part no,however in the search it comes up with various manufacturers mostly in china.
Now the number above appears on the black plastic cover,that fits all of three caps that I have,all of which differ as previously stated.
My main concern is not the internal differance,which I find odd,but with the variation in the distance from the base of the cap and where the clip locates.
These are the measurments
Beru cap 11.7 mm
GSf cap 14,6
cap which was on the car when I bought it 13.6
There is a differance of over 3mm clamping distance,and i found it was always hard to get the second clip to locate,and one would assume that the more pressure the better,as far as hollding the cap is conserned,even takeing in to account there is a locater on the cap.
To add to this on all the used caps I have, there are black shiney marks caused by friction, where the caps are moving around on the dizzy base.
Which means the Beru cap,which appears to be the best quality item is the worst on the clamping issue.
This leads me to think,given that most people agree that the rotor arm is the wrong size,and shouild be the narrow tip,perhaps the newer cap with the stronger clamping force should be used . Think about it Audi never said anything about the wrong part number on the rotor arm
So why would they mention any problem with the cap.easier to just make sure all replacement caps have the higher clamping force.

[s2driveruk]

got any pictures - am about to do some work and I will prob renew the cap too.

[mcandmar]

From memory when i replaced them on my 7A many moons ago they are Bosch parts.

[4WheelDrifter]

You bought a distributor cap from GSF? Shame on you Lou!

[220bhp]