HiIntercoolers are for FI engines (FI = Forced Induction...... supercharger or turbocharger) NOT NA (normally aspirated). Yes, you could add one, but it won't do anything for performance except to lighten your wallet.
When you compress a gas (like air) it heats up. The more you compress it, the more it heats up. Warm/hot air has less oxygen molecules in it, thus you add less fuel and get less power. The hot air can also cause detonation/knock which is bad for your engine. The intercooler drops the temp down of the compressed air making a number of gains.
Sorry have not seen this Message until today. Yes the trouble is solved. What I did was.
The two exhaust cams are different. And as they did not have any mark I had 50% chance to get it right, but I didn`t. I mounted the cam which was ment for the front line to the rear line. Lucky that nothing was damaged. Now the car has a beautiful sound and run With no trouble.
Thank you very much for helping.