would like to know if anyone can show me the difference or tell me the difference in small and big block cross members for 67,68,69 camaros.//thanks

Small block crossmembers have a Square cutout in the middle where the 2 trans mount bolts go through. Big Block crossmembers have a irregular shape, not square. I think also Pontiac Firebird crossmembers are the same as Big Block, but i am not positive on this. Check under a few Firebirds and compare. Hope this Helps.

The BB/manual crossmember has the trans mounting holes offset 1" to the right; they may also be slightly farther forward. It is similar in appearance to the sb crossmember.

I have heard that using the later 1-bolt trans mount with a sb crossmember will also work for a bb.

All sb use the same crossmember.

The BB/T400 crossmember is unique to that application. It may still be available from GM.

Do you have any part numbers for that 1-bolt trans mount.

My car is a small block car with a bigblock in it. i am at the moment collecting the parts to get it the right position but still lacks the crossmember, I found what I think is the BB/T400 but it looks to me as if the mounts are in the same position as the SB crossmember.

Jan

Jan, The big block turbo 400 crossmember is quite unique in appearance . It starts out flat at the outsides and then changes to a almost round shape. There is a channel type bracket with 2 slots welded forward in the centre. This crossmember IS still availiable from GM, the part number is #3912573. It fits 67-69 Camaro. Hope this helps.

A BB stick cross member has a rectangular transmission mount hole in it that has the drivers side corner cut at a 45 degree angle. (I.e., drivers seat, drivers rear pass. seat, front pass. seat and rear pass. seat sorta thing)

I saved this from earlier from somewhere!! Thought it might come in handy b/c of my pointy little head's poor short memory!!

pdq67

I have one of each laying in the floor in my shop. The big block cross member has the holes offset 1/2 inch farther to the passenger's side. I can take pictures and send them to you in the next few days if you want them.

Here are the two 4 speed cross members. The small block is on top and the big block is on bottom. http://community.webshots.com/photo/111240158/111243774SQvToN http://community.webshots.com/photo/111240158/111243572mYaqOm

the one bolt mount is the same as for a 200-4r such as out of a mid 80's monte carlo.

i havent tried one, but i have seen them.

all 1stgen firebird v8's were big block cars, but not all of them had the th400. the 400 mount is farther forward than the st300 2 spd mount. i do not know what the BB crossmember for the 2spd looks like, but it should still be offset to the right on a BB.
the sb camaro crossmember is the same as the 6cyl firebird because there was no offset. the auto/6cy birds came with the st300 2spd.

i also think the 2spd crossmembers are the same as the standard transmission crossmembers, but i could be wrong.

you can order a repro th400/BB crossmember for about $65.