Went hunting around for a 3.4 and found one from a 93 camaro, 142,000KM on it and is being sold for 350 Dollars. I want to do the swap because the 2.8 in my car at the moment has 297,000KM on it! It was rediculously well taken care of but i would rather just put in a lower KM engine over the winter. Basically when I'm doing this swap, I wanna have the 3.4 have a bit more kick in it then the 2.8 for around the city. Since the Engine would be on a engine stand for a few months ill be able to replace quit a few internal stuff. Now I've been reading around, and the 3.4 Hybrid has intrigued me quite a bit. I'm basically wondering, for the 3.4 Hybrid, would I need the 3.4 wiring harness, and the the heads, pistons, intake manifold and that? Can i buy headers or manifold to fit onto the heads, or do they have to be custom?

Or is it easier for me to just replace most the stuff in the 3.4, add a cam, CAI, headers and full exhaust and be done with it?

I basically want something that will be fast in the city. I rarely do highway driving and i got a T-5 so im not looking for performance on the highway.

 

Since you are getting a 3.4 and are interested in a top end swap you have the igntion problem solved but only if you get the 3.4 harness with it. The 3400 top end flow much better than the iron heads. If you get headers you will have to slot the holes on them to bolt up but otherwise they match up to the ports. You might as well add a cam to it for some more power.

 

The 3400 has D shaped ports, so you will alo need to modify the primaries for that. May be easier to cut off the gen I flanges and weld on gen III flanges.

You don't need the 3.4 or 3400 harness, infact that would complicate things.
Just use the 2.8 harness, with a few modifications. The harness that goes between the CPS (Crank Position Sensor) and the ICM (Ignition Control Module), is seperate from the main harness.
The signals between the ECM and the ICM are esentially the same between the DIS and vehicles (3.8/3800 is an exception). You will just have to change the plugs.
The Fuel injectors change position slightly and also the IAC, TPS use different connectors, but simple cut and splice will take care of these items.

The hybrid uses the RWD front cover for water pump and such and to retain the original belt driven accessories, though the brackets that attach to the ends of the heads will need some modification or fabricated from scratch.

The 3400 intake can be turned around to face the front of the vehicle, so the stock pices can be used here.
You will need 3400 pistons to keep the SCR (Static Compression Ratio) in check. Would be 9.6:1, since you have only one option for the head gasket and that is the 3400 headgaskets, since the 3400 pistons come proud of the block by about .020". The 3400 gasket is .060" compressed thickness yeilding a nice .040" quench hight. Hybrid swap is extra work, yes, but very worth it in the end.

 

so i could drop the 3.4 from a 4th gen in my car and just modify the Harness a bit and it would work or do i need the later SFI ECM? does the ECM use the Crank sensor or does the ICM do that all on its own?

 

If you use the 3.4, in a non-hybrid form, yes you can use your existing harness as is, since you have to swap the intake out to use the dizzy from your current engine. I have seen information on one person modifying the 3.4 intake to clear a dizzy, though I don't feel it would be worth it looking at the 3.4 intake itself, it's not any better than the 2.8/3.1 intake from what I have seen.

To use DIS, you will need to at least modify some of the bin code, to setr the trigger angle to the correct setting.
You should be able to get the 3.4 to work with the DIS in much the same way it would take to make it work with the hybrid, using the existing harness.

The 3.4 SFI PCM requires a few things that become either a nusence, or just plain problematic, like bypassing the VATS system, while not impossible, it does require building a circuit that will provide the PCM with the proper square wave frequency to allow the PCM to fire the injectors.
The 3.4 PCM has also not been hacked, so any additional tuning is not supported at this point in time, and it seems that most people that were working on that have given up and gone other routes, for tuning.

There are however documented hacks for the FWD ECMS that will run the 3.4 or 3.4 hybrid, and have been used very successfully in everything from mild N/A builds to wild turbo builds on engines ranging from 2.8L, to 3.5L that I have seen.

 

Alright so from what i understand:

-I can keep the 2.8L Harness in the car, But i will need to change over some sensors, correct?

-Going to need the make some accesorry brackets for the heads to put on becuase they will be different, correct?

My last question is about headers. What would i do about that?I remember reading in how the pacesetter headers would not bolt up to the heads, so would the exhaust have to be custom made?

and also how much you think this is gonna cost me? I got quite a bit of cash coming in real soon so it's not a huge worry but i would still like to know.

 

If you don't mind 11.16:1SCR (3500 head gaskets), a 3500 top end can be used. With a little modification to the spark plug area, I think 11:1 is very feasable.

F-body headers will work, just need to notch the flange to bolt to the wider holes on the 3x00 heads, but unless you use at least 1 5/8" primaries some of the port might be blocked by the flange.

 

You can use the 2.8 harness if you splice the 3400 connector plugs in, you will need to make a few brackets to mount things up and you can use pacesetter's headers if you cut of the flanges and weld gen 3 flanges in place (and possibly do a little bending to the primaries). No need for a custom exhaust, unless you have the money for it in which case go for it. As far as cost is concerned- any time you start a project add up what you think it will cost then double it. Heh, just kidding but your budget needs to be flexible.