I own a 1986 626 2.0 8v.
Do any of you know if it's possible to take the dohc
cylinder head of a GT model (late 80's) and install it on my 8v engine?

Is it the same engine block, and are the cyl. head bolts
installed on the same places (same distance between bolts, same ammount of bolts)?

I am only guessing but I am think its a 12 valve not a 16 valve.You have an identical car like mine and I would love if it fits.

not sure where you are located but if you are talking about the 8 valve to the 12 valve i can help. I have a 86 myself and just did a engine swap with a 91 2.2L 12 valve. the block in the 2.0 and the 2.2 is the same but the 2.2 has a bigger bore and little longer stroke. if you are talking about a dohc the block maybe the same but check the pistons to see if they have notches cut in them.

There were many many differnt versions of the F-series motor, all over the world. I'm not gonna get into listing them, but I'll say:

In Europe and Japan there was a version called the FE3, it had the 16v head. That motor is now in the KIA Sportage, if you can believe it, though it is tuned for being in a truck and has less quality (no oil squirters for under the pistons, and the crank isn't forged like in the FE3)

You can use a 99+ sportage head though, to adapt to an F or F2 motor...the oil drainage holes in the 97-98(?) don't line up or something. Of course you'd need new pistons and Im not sure what timing belt you'd use (since the deck height is differenct.) But it's been done before several times.

I've heard one of 3 Toyata Supra timing belts will work with the Kia Sportiage head swap.

You can swap a 12 Valve head on there, the problem is the probe head has the distrubtor at the back, so unless you are going to do some major modifications to your firewall I wouldnt think going that route is any good. Someone said they had done it, I'm curious as to how they did this. My other question is why do you want a 12V head? 16V I can see, and as has been explained the FE3 did have DOHC 16V very hard to find the actual mazda version. The kia version is out there, and if you do that, you need more than a head, you need a head, and intake manifold, all the injectors, the computer, the wiring harness etc. along with the exhaust manifold I think. I would like to see how someone did the 12Valve but personally I did out my 8 Valve and I am really please, I just did a 3 angle valve grind, oversized the valves a little, polished it and such and it flows pretty good. and its very very tough. I've done a lot of stuff so if you have any questions about doing yours up you can email me. I just installed my new header, think I'll go take it for a spin!