I have been given a MVVS 6.5 engine by that has a brown anodized head. The serial number under the motor mount flange reads #1896 on one side and the letter "R" on the other side. It has been completely rebuilt according to the previous owner who had it done in the Chech Republic. It has side exhaust. It also came with a tuned pipe and 2 different headers. Can you tell me what engine this is?