Ok, to explain my question, yesterday i bought a USDM 1990 Civic Si Hatchback from a local tuner shop here in town. The guy that owns the place sold it to me as a stock Si model with 186,000 miles on it... however... when i cleaned off the engine plate to see if it still had the D16A6 in it... i read the letters "ZC" on it... so now i found out that my 1990 USDM Civic Si Hatchback has a SOHC ZC engine in it... ok now my question is... Since it is a ZC... is it possible to put the Dual Cam ZC head on the Single Cam ZC engine... i would figure it would be possibel since its a ZC... the block would be the same as the Dual Cam model... i would love to get some Feedback please!!!!!

 

I'm 95 percent sure that the blocks are not the same. You cannot put a dohc head on a sohc block.

 

Alot of people say that... however... i do know that you can put a 4G63 DOHC head on a 4G64 SOHC Mitsubishi block... so i dont see why i couldnt do it with the same model engine in a honda... everyone says you cant put DOHC tops on SOHC bottoms... but i have seen it done on a mitsu... so i am not gonna absolutely base my conclusion and opinion on that statement... cause i know for a fact the DOHC wont fit SOHC block thing is not true. it may be in most cases... but not in all... and i think this may be an acception... some more feedback from other users would be helpful, like i said... i have gotten both yes and no's... i need a solid answer and a reasonable statement on WHY it will not work if you say no... otherwise i will still think that some little chance... it MAY BE possible... not saying it is... but MIGHT be if you cant give me a ligitiment answer why it wont work.

 

I've heard that the bolt spots are in the same place but the holes for the DOHC are bigger than on the SOHC so it won't bolt on.

 

bah... i guess ill just have to go back to the tuner shop tomorrow and talk to the guy i bought the car from about it... i mean... yes thanks for posting you all... that helps out a little bit... but they are not solid enough answers or reasons to say yay or nay... cause there are so many people that "hear" things that arent true... but thanks for the feedback... ill just go check it out at FasTECH tomorrow.

 

yeah good Idea go back to the "tuner" that said he sold you a stock si. Must not be very good if he doesn't know what a sohc zc is. BTW this topic had been covered and it was proven that it can't be done.

 

From what I understand, the DOHC head will not fit on a SOHC block. The SOHC ZC is the Japanese equivalent of the U.S. D16A6. If you want the DOHC ZC, just buy the whole engine, it isn't that expensive for an engine swap and bolts right up to the stock transaxle.

 

No, the oil and water ports are all wrong. From what I know, all the normal d16a6 parts will fit with no modification so technically, it's an equivalent. Also, the sohc ZC is the equivalent to a sohc 120ish hp. So you might have come out on top.