3100-3400 Questions

[natehead]

I have a '98 century with a 3100 and also have a '00 3400 out of a grand am(I think). I am new to the 60 v6's, so I was wondering if anyone has any input on if any combination of parts is better than the other. The 3100 has some noise in the bottom end, and the 3400 needs a head gasket, but the rotating assy. is smooth as butter. I have asked around and heard that the heads of the 3rd gen. 3100 are more efficient than the 3400's, but as to the validity of that..... or if they even interchange. Please fill in some blanks for me.

Also what are my other options(totaly diferent heads, boost?), I would like to stick with the 3400 bottom end, this will be going into my '98 century.

[Rhedalert]

Use everything off the '00 3400. Its manifolds and heads are preferred over the '94-99 variety. You'll only need to deal with two things: You'll need a '00+ EGR (wiring is the same though, lucky for you ) and the coolant outlet pipe that fastens to the lower intake manifold. If your donor motor doesn't have it, you could pick up a new one from the dealer along with the O-ring, it's inexpensive. It will be an easy swap for you.


EDIT: If it is in fact from a Grand AM, you MIGHT have to swap or modify the front timing cover if the Grand Am style mounting boss gets in the way. You'll see the difference when you look at it.

[bszopi]

When discussing the efficiency of the heads, someone probably got confused with the 3.4L iron heads and the 3400 aluminum heads. With the exception of valve sizes, the pre-00 3100 and 3400 heads are exactly the same (3400 having the larger valves).

[natehead]

So you suggest straight-up swapping in the 3400? If so, what is the 3500 hybrid? I have been having trouble navigating the site for some reason. If I'm going to do the whole swap, I might as well do-up the 3400 completely while its out and on a stand, it will be a daily driver and I am open for mild to wild(more towards wild). If anyone has some suggestions and some realistic number gains, please let me know.

Also, depending on what it ends up like, I will have to address the tranny. I don't run the tar out of my cars, but do enjoy some wot driving now and again.

[3100 MPFI]

for the most part, a 3400 is nothing but a 3100 with a larger bore.

There were some changes made, such as the 3400 having a larger intake manifold than the early 3100's.

If you are going to be rebuilding a 3400, then I would swap it in. That little extra displacement will give you a nice boost.

As for the 3500 hybrid, that is using 3500 heads, lower, and upper intake on a 3400. It can't be done on the 3100. The 3100's cylinder bore is too small, and the valves will hit.

The 3500 is an even more updated design, and flows even better than the 3400 stuff. The 3500 upper intake manifold can be modified to be used on a large port 3100 and 3400 lower intake manifold.