From the Archives
OK everyone. Here is what I found out by taking detailed looks and some measurements. In regards to the intake and exhaust ports. They are the same size. Same bolt pattern. The only thing I found is on the 2.0L NON-Jet head there is a small hole that connects the exhaust ports together using a common rail in the head. This is for the fresh air injection into the exhaust. You will need to plug them.. As for the intake ports the 2.0 head is missing the cute little grove that connects the jet valves to the intake. The only BIG change is the depth of the combustion chamber and the exhaust valve is dished this gives it just a little more CC. This along with the extra depth of the combustion chamber makes it a 2.6. They might have a different rods but I'm not going into the block. So the answer for the early First Gen is YES get a 2.0L head and stick it on your 2.6L but the fuel pump DOES NOT FIT. You will need a 2.0L fuel pump. The change over happened in 1983. Then there are some major changes. On the intake manifold the 2.6L has a tube for the air jet system. Just take a look and see if the port is blocked by a flat spot on the head and the gasket. Last is the fuel pump hole. It is just slightly different. Studs not bolts. I will update this page as I do the swap. NOTE Make sure you use thicker gaskets. This will keep the compression the same. If necessary use shims. Take your head to a machine shop have them check to see how thick it is. If the head has been surfaced or planed you must a thicker head gasket. If you don't you can have timing chain problems. Then the chain is to long and the cam timing is retarded along with the adjuster out of speck. If the gasket is to thick then the cam timing is advanced, this is better then retarded. If unsure what to do go with advanced. You can correct this with ignition timing...... Use a 0.073 thickness head gasket if you have had any machine work to the head or block or the parts are not standard, so you will need the thicker gaskets.
first gen Head 54.50 CC
2.0L first gen Head 55.90 CC
Measured head thickness. Head gasket surface to valve cover surface.
NEW: 3.543 - 3.548 inch's
Minimum 3.523 inch's. Anything less your head is junk.
NOTE THE AIR INJECTION HOLES. YOU WILL NEED TO PLUG THEM OR YOU WILL HAVE AN EXHAUST LEEK..
VALVES ARE THE SAME
AIR INJECTION PORT.