I could swear that I saw a thread with pictures of the 3.5L (from the plastic intake era) and 3.7L lower intake manifolds side by side, but my search-fu is failing me. Anyone have pics of the two, or of the VQ35 lower intake top and bottom?

 

I can get you one. The difference is the fuel rail mounting point. Both lower runners will mount to either engine. The HR will accept an HR upper, and the VHR the VHR upper. However if you are looking to put a HR upper and lower on a VHR, you will need the HR fuel rails as well.

Oh, and runner length is the same on the lower runners (between HR and VHR).

 

So IIRC bolt holes 1 and 5 (L to R) on the top side in the photo and again on the bottom side were the mounting points for the fuel injector rails. How substantially different are we talking?

(btw, not my photo, grabbed from internet search - PM me if yours and I will attribute properly)