I know this has been asked before... sort of. As I understand the 6L90E will not fit without modification. My question is, "How much modification are we talking about?"

I can handle a little tunnel lift, and even a little wider. I'm pretty sure I can trim the interior parts to fit an extra inch or two of tunnel.

Just wondering if anyone has an idea about how much I need to cut and move.

Thanks!

 

Have you checked the transmission and drivetrain forum? I haven't looked there personally, but have seen 4L80E swaps discussed (both on that and this forum). The 6L90E should fit as easily with crossmember modifications.

I was considering one for the '57, but will probably stick with the 4L80E since I already have it.

 

last i knew (and i may be wrong on this one), the 6l90e was a larger housing than the 4l80e, so the tunnel would have to be enlarged. also, it requires a gen4 (dbw) harness, since it will not work with a gen3 setup

 

You may be both wrong and right. I searched around for a long time, it appears the 6L90E is not as big around as the 4L80E at the front (behind the bellhousing), but it doesn't taper off as much in the back, requiring tunnel work. I did see on more than one source that it weighs less than the 4L80E.

Speartech apparently put an LS9/6L90E into a '91 Camaro, but I couldn't find anything about the transmission install itself. Before that they had a 4L70E in it, that didn't require tunnel mods.