1998 monte LS swap

[whyfor90]

I have a 1998 monte with the 3100 in it. I'm looking at getting a 3.4 DOHC from a 1996 monte carlo that has 88,000 miles on it. What all do I need for it to work. If the stock ecu will work but not as well as the 3.4's that will be fine for me now. I know the tranny is the same but what about wiring harness, fuel lines, vaccum lines ect...

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[whyfor90]

No one knows? Please help. Ive googled the crap out of this and cant find anything straight.

[pocket-rocket]

Well, you did only give people 1 hour on a section of the board that is barely browsed. 2/3 of this site, if not more is devoted to the pushrod engines, it's a lot bigger section of the 60v6 family, and is still in production in much larger numbers than the DOHC was. Us DOHC guys are a dying breed.

There is a member on here named jmgtp that did just the exact opposite of what you want to do (he removed his DOHC and put a 3500 in its place). Here is his build thread:

http://60degreev6.com/forum/showthre...-few-questions

As far as I know, the 3100 harness can be made to be used with the DOHC with some changes. John used his DOHC harness on his 3500. Also, he is running his 3500 (an engine that came in OBD2 cars) on his OBD1 ECM. The vacuum lines are different between engines, but if you get a complete engine with hoses, ect., that should be the least of your concerns. You will also have to have the PCM retuned afterward to get the most out of the new power plant. If I were you, I would go through Johns entire build thread, page by page, and see what he had to do/change over/modify/retrofit to put a 3500 in his car. That should give you an idea on what you need to do, or at least a starting place to get a DOHC in your car. If you ask the pushrod guy, though, they will probably call you crazy since the pushrods actually have an aftermarket, even though it's a small one, it's still larger than the aftermarket for the DOHC.

[whyfor90]

I didn't realize this part was so deserted. I was getting a little impatient due to googling it and scouring forums for days with no info. Thanks a lot for your help though I really appreciate it.

[pocket-rocket]

It's no problem

I understand impatience, I get the same way. It does suck that the DOHC never got to live up to its full potential. There's one guy on here with a turbo DOHC in a really really nicely done Fiero Ferrari replica that layed down some really nice numbers on a basically stock engine. I think it was something like 350-450 hp to the tires, and the car was done beautifully.

BTW, welcome to the site