Hey Everyone,

As I am amassing the plethora of parts for the engine install, I am wondering if I need a crossmember. The one I have from the 350/powerglide looks like the BB 4spd but I am assuming that looks are deceiving. Do I need to order up a new crossmember? I will have a 427 and an M-21.

Thanks!

Bill

You are correct... you need a crossmember specific for big block 4 speed cars. I went through this same thing... I found I had a small block cross member in an original big block 4 speed car (how does that happen?).

The difference is in the mounting hole locations for the trans crossmember... with the big block version having the holes offset towards the passenger side to compensate for the offet motor mounts used on big blocks. The big block version does have a visual difference... the shape of the recessed pocket where the trans holes are is square shaped with a notch out of one corner, while the small block version is an oval shape.

Check out these links...
http://www.camaros.org/trans.shtml#Crossmembers
http://www.camaros.net/forums/showthread.php?t=124206

You technically could use your old crossmember, but I definitely recommend getting the correct one. Using the wrong one could become a source for driveshaft angle problems resulting in excess vibration (which is what was wrong with mine when I bought the car). The correct crossmember is available now in reproduction. I got mine on ebay through Heartbeat City.

~Bob

A picture, and a correction...

I knew I found a picture of one on here somewhere. It was driving me crazy, so I looked until I found it:
http://i45.photobucket.com/albums/f58/markx22/1969%20shifter/crossmember1.jpg

That's a big block crossmember... showing the square-ish (actually, rectangle) pocket with the notched corner where holes are. That's what you need. It's from this thread...
http://www.camaros.net/forums/showthread.php?t=103424

FYI though... I didn't get it from Heartbeat City like I said. I double checked (memory isn't what it used to be)... I got mine from Firewheel Classics. I was going to get it on ebay, but ended up needing to go to Firewheel for something else (they're local to me) so I just got it through them.

~Bob