'86 e30 motor swap

[Heavy_Rain 0]

Completely new to bmws but I got a '86 e30 325i that I was told had an m20b20 in it..got another m20b20 motor with the car that I was told was from a 1990..It has the distributor on the front..has 1288322 stamped on the side of the block

the motor i pulled out has 1278849 stamped on the side..can I swap the heads round and make it work?

[E30 325i Rag-Top 2956]

Yes you can in theory. The earlier "L-jet" motor with the dizzy on the side of the block usually comes with higher compression pistons than the later "Motronic" engine (dizzy on the front) but the later engines have better fuel / spark timing. I don't know what you are looking for from your engine swap, but fwiw the highest power from the E30 Race Series engines was made by putting the later head and engine control electrics on top of the earlier L-Jet bottom end.

If you want to just swap the head over then you can keep the exhaust manifolds, inlet manifold, etc. and just block off the dizzy hole at the front with a plate is the easiest option. This save a bit of mucking about with the electrics plugs, etc.

[Mr Vapour 76]

why has your 325 got a b20 in it. Would you not be wanting to put a b25 back in?  

or are you racing in the 2.0l BMW class ??