Question about the 3500 top end.

[Sidewinder]

I know this has been asked many times before, but I wanted to get a second opinion and some clarification.

I've heard that a 3500 top swap (so the heads as well as the intake manis) will work on a 3100 block, and the reasoning for this was that the distance across the valves on 3500 heads is 3 5/16" and the distance across the valves on 3400 heads is also 3 5/16". 3400 heads work on a 3100, so by this measurement the 3500 heads should work as well.

I have no idea if this is true, so I was hoping to get some clarification.

[95Grand-Am]

The combuston chamber is bigger on the 3500 then the 3100 & 3400. The fire ring on the 3100 headgasket will partially be inside the chamber of the 3500 combution chamber. If you really want to put 3500 heads on a 3100 you might be able to put 3400 head gaskets on it to make it work?

[SappySE107]

Still a bad idea. Maybe if you cut the cylinder at the top but even then, I don't know. Certainly not optimal.

[Sidewinder]

Ok that makes sense, thanks for the information. I just wanted to be sure about that before I ran out getting the parts. I did recall you saying that it wasn't a good idea either, but I just couldn't remember.

What got me confused is that the source of this information never mentioned that there would be any issues and that it would just work.

[ForcedFirebird]

The chamber is over 91mm wide on the 3500 heads...

http://i158.photobucket.com/albums/t...s/100_3027.jpg

[Ortie666]

coulden't you use a 3500 gasket then mabye bevel the edge on the cylender?