Question about BB 4speed crossmember
 

I have a 68 Camaro that I put a BB 427 in last year.The car was a roller but the previous owner had a BB 454 in it. My question is I was told that the crossmember under the transmission is a small block one because of the oval opening instead of the well known square type. The holes are offset to the passenger side in the oval opening instead of being centered in the opening. I just talked to a restoration parts person who said that he has seen GM numbered crossmembers with the oval opening. Has anyone else seen this? I used the BB motor mounts and didn't have much trouble bolting up. Is it possible to even bolt up correctly if I'm using the wrong crossmember?

Re: Question about BB 4speed crossmember
 

Good question. I've seen plenty of fake BB 69 Camaros with
the oval hole X-member. However, every real BB 4-speed I
have ever seen has the squared-off hole.

I actually never did get a real good answer as to why the
BB 4-speed X-member exists anyway. Aside from the hole
difference, and the large dimple on the upper passenger
side, they appear to be the same. What is the actual
positional difference of the transmission in conjunction
with each of these X-members? Surely someone here used a
SB X-member on a Camaro once.

Steve

Re: Question about BB 4speed crossmember
 

If you use small black frame and motor mounts. The small block cross member works fine. If you swith to big block fram mounts. The motor moves up and over to pass side. Then you will need a big block cross member to line up trans mount. I found out the hard way. Earl

Re: Question about BB 4speed crossmember
 

Steve, I'm not really concerned if the crossmember is original GM although the guy I talked to said that he has seen them with GM numbers on them as much as I just want to make sure that it is a BB Xmember. Were the oval hole ones that you have seen aftermarket ones? This one has the original holes (slots) in it with no other holes so it isn't modified. Does anyone know if the holes in a SB Xmember centered in the oval opening? These holes in mine are about 1/2"-3/4" offset to the right like a BB should be. This crossmember has been in the car at least 17 years or more so I can't picture anyone having an aftermarket one out then since most of this aftermarket Phenomenon as being more current. In fact, I don't even recall anyone manufacturing a BB 4 speed Xmember at the present. I may be wrong.

Re: Question about BB 4speed crossmember
 

The only BB 4-speed X-members I've seen have the square hole/diagonal cut and the offset trans mount holes. Earl explained the reason for the offset on the mount holes. Attached is a topside pic of a Camaro BB unit. I believe Heart Beat City reproduces these.

Can you post pics of the top & bottom side of the one you have?

https://www.yenko.net/ubbthreads/imag...mlins/flag.gif

Re: Question about BB 4speed crossmember
 

The exhaust is also laid in at an angle in the BB.Where it is straight on a SB.Jeff

Re: Question about BB 4speed crossmember
 

Yes,

HeartBeatCity does sell a reproduction. I looks quite
nice too. They are on eBay constantly as repro's &
originals. Just be careful that you don't get a Firebird
X-member by mistake. They have the mount holes in a
different location. I found that out the hard way....

Steve

Re: Question about BB 4speed crossmember
 

[ QUOTE ]
Steve, I'm not really concerned if the crossmember is original GM although the guy I talked to said that he has seen them with GM numbers on them as much as I just want to make sure that it is a BB Xmember. Were the oval hole ones that you have seen aftermarket ones? This one has the original holes (slots) in it with no other holes so it isn't modified. Does anyone know if the holes in a SB Xmember centered in the oval opening? These holes in mine are about 1/2"-3/4" offset to the right like a BB should be. This crossmember has been in the car at least 17 years or more so I can't picture anyone having an aftermarket one out then since most of this aftermarket Phenomenon as being more current. In fact, I don't even recall anyone manufacturing a BB 4 speed Xmember at the present. I may be wrong.

[/ QUOTE ]

Darrell,

To help, see if you can get the engine frame mount part
numbers. These are stamped on the flange surface between
the upper two bolt holes. If big block mounts, then you
need the BB X-member. Again, repro's are on eBay.

Steve

Re: Question about BB 4speed crossmember
 

[ QUOTE ]
The exhaust is also laid in at an angle in the BB.Where it is straight on a SB.Jeff

[/ QUOTE ]

Jeff,

On the X-member, what about the exhaust issue are you referring to?

Steve

Re: Question about BB 4speed crossmember
 

Ed & Steve, The only picture that I have is one taken from under the car showing only the oval opening and the two transmission bolts offset to the passenger side of the opening. I tried to accessing my web picture hosting site but keep getting an error message. Either they are down or kaput. Steve, If the part numbers on on the top of the flange, I don't believe that I'll have access to see them with everything being in the car. I know for sure that the engine is on BB engine mounts and is offset by about an 1" to the passenger side of the engine compartment. I just can't see the engine lining up to a SB Xmember with the engine in that position. I'm still waiting for someone to tell me if the two holes in a small block Xmember is centered in the oval opening or offset towards the passenger side like mine. If you think that the picture that I have of the oval opening would help, I can email you the picture. By the way thanks for your help. much appreciated.
Darrell

Re: Question about BB 4speed crossmember
 

I forgot to ask. Does the same BB 4 speed crossmember fit all three years 1967-1969?

Re: Question about BB 4speed crossmember
 

The two humps also start out wider and end up narrower.The bb exhaust is wider than the small block at the front.Hard to explain but side by side is obvious.Jeff https://www.yenko.net/ubbthreads/imag...ns/burnout.gif

Re: Question about BB 4speed crossmember
 

Ohio427;

I have sb and bb crossmember pictures on my site on a transmission crossmember identification page. The focus is the Nova, but they used the same sub frame. It does not go into differences (if any) by year, but provides a way to see the crossmembers side by side.

The pictures are right under the transmission code table on this page: Nova Crossmember Identification

Greg R.

Re: Question about BB 4speed crossmember
 

Greg,

That's top-notch documentation you have on that site.

As the saying goes, a picture is worth a thousand words.

Steve

Re: Question about BB 4speed crossmember
 

There is a 1/2" offset towards the passenger's side on the BB Xmember. You can use SB engine mounts with a BB Xmember, you just have to muscle the tail of the trans over to get the bolts to line up. Every 4speed Yenko Deuce was built this way!

Re: Question about BB 4speed crossmember
 

[ QUOTE ]
I forgot to ask. Does the same BB 4 speed crossmember fit all three years 1967-1969?

[/ QUOTE ]

To the best of my knowledge, yes.

Ed https://www.yenko.net/ubbthreads/imag...mlins/flag.gif

Re: Question about BB 4speed crossmember
 

Greg, great site you have there. The pictures tell me what I wanted to know. The picture of the SB crossmember is exactly like mine. It shows the bolt holes to the right of the opening. I just don't understand how mine bolted up with BB engine mounts and SB Xmember. Do you guys think that I should replace the SB with a BB xmember. I worry now that with this combination that I am putting undue stress on some part of the drivetrain whether it be the rear end, transmision or engine itself. It just seems like something has to be taking the force of the 1/2". I have put over 500 miles on this setup and haven't noticed anything unusual like an engine or drivetrain noise or vibration.

Re: Question about BB 4speed crossmember
 

Your setup is fine, there are deuces with 100k+ miles on them with the mis-matched components - without problems! The universal joints make up for any alignment issues. I'm not sure I'd be throwing a set of slicks & caltracs on there, but for 'normal' usage it will be ok.

Re: Question about BB 4speed crossmember
 

Marlin, Thank you. That's what I have been wanting to hear. I'd hate to go through changing anything when everything runs well as is. With my luck, the new & right crossmember would probably not line up while I had no problems with the wrong Xmember. I was just afraid of something developing in the future because of this. This site is truely a treasure of knowledge. Thanks to all.

Re: Question about BB 4speed crossmember
 

Good info here Gents on a much over-looked topic. Allow me to add a little more:

The OEM shifter mounting holes are different relative to the tranny mounting holes on big block xmembers. They are offset to the left about 1/4" compared to SB. This allows the BB shifter linkage to align correctly. Yes, a mismatch will work, but thats not the way they were from the factory.

This applys only to 67-8 Camaros.

Re: Question about BB 4speed crossmember
 

Hmmmm... I thought the shifter rods made up that difference, but not completely sure https://www.yenko.net/ubbthreads/imag...lins/dunno.gif

Re: Question about BB 4speed crossmember
 

[ QUOTE ]
Your setup is fine, there are deuces with 100k+ miles on them with the mis-matched components - without problems! The universal joints make up for any alignment issues. I'm not sure I'd be throwing a set of slicks & caltracs on there, but for 'normal' usage it will be ok.

[/ QUOTE ]

Marlin,

I'm a little confused here. The Deuces are LT-1 drive
trains and as such would use a SB X-member - right?

Also, if the SB works, why did GM use the special BB
4-speed X-member we are discussing here? As I mentioned
earlier, every BB 4-speed Camaro I ever saw ( correct )
used this special X-member. You're obviously knowledgeable
about this stuff and I hate to disagree with you, but I
just don't see the SB X-member being correct. I'd welcome
your comments otherwise. Always good to learn from others.

Steve

Re: Question about BB 4speed crossmember
 

[ QUOTE ]
Good info here Gents on a much over-looked topic. Allow me to add a little more:

The OEM shifter mounting holes are different relative to the tranny mounting holes on big block xmembers. They are offset to the left about 1/4" compared to SB. This allows the BB shifter linkage to align correctly. Yes, a mismatch will work, but thats not the way they were from the factory.

This applys only to 67-8 Camaros.

[/ QUOTE ]

69 only has a similar issue. The shifter rods are about
1/3" longer to accomodate the mounting of the shifter with
that special ( again, BB only ) horseshoe mounting plate.

69 BB's have lots of these accociated issues. The lower
reverse lockout rod is also different for BB 4-speeds.
The flat nut for the Hurst shifter adjustment is a racetrack
shape vs. the rectangular shape of the SB's. Once you start
you just can't stop. https://www.yenko.net/ubbthreads/imag...s/rolleyes.gif https://www.yenko.net/ubbthreads/images/graemlins/no.gif

Steve

Re: Question about BB 4speed crossmember
 

I hear ya! We actually don't know why GM installed the BB transmission crossmember with the LT1 application. We have confirmed that the engine mounts are indeed the SB version, and the crossmember is not the Pontiac version. I wish I could tell you why, but.... that's GM https://www.yenko.net/ubbthreads/imag...lins/dunno.gif

We have speculated that the BB Xmember was retained under the COPO 9737 package because that package had been applicable to only BB cars for the prior two years, but we agree that it's a stretch and pure speculation.

The deuces actually have the BB shifter rods, but the SB shifter attaching bracket (no 1/2" offset), along with the '69 Camaro Z28 shifter mechanism with a Pontiac GTO bench seat arm. Confused yet? https://www.yenko.net/ubbthreads/imag...mlins/grin.gif

Re: Question about BB 4speed crossmember
 

No,

But you pretty much ruined my day https://www.yenko.net/ubbthreads/imag...ins/tongue.gif https://www.yenko.net/ubbthreads/imag...mlins/grin.gif

Re: Question about BB 4speed crossmember
 

[ QUOTE ]
Hmmmm... I thought the shifter rods made up that difference, but not completely sure https://www.yenko.net/ubbthreads/imag...lins/dunno.gif

[/ QUOTE ]

Many people think there is no differance. The BB linkage and the stablizer shaft are offset to align with the BB xmember. The assembly manuals show this and I've noted it on a number of unmolested BB cars thru the years.

Re: Question about BB 4speed crossmember
 

[ QUOTE ]
[ QUOTE ]
Hmmmm... I thought the shifter rods made up that difference, but not completely sure https://www.yenko.net/ubbthreads/imag...lins/dunno.gif

[/ QUOTE ]

Many people think there is no differance. The BB linkage and the stablizer shaft are offset to align with the BB xmember. The assembly manuals show this and I've noted it on a number of unmolested BB cars thru the years.

[/ QUOTE ]

Craig,

What's a stablizer shaft? https://www.yenko.net/ubbthreads/imag...lins/dunno.gif

Steve

Re: Question about BB 4speed crossmember
 

Steve,

The stabilizer shaft attaches to the shifter body, extends foreward, and attaches to the tranny via a bracket. The 69 factory Hurst didn't have one.

Re: Question about BB 4speed crossmember
 

Oh, I got you, the Muncie shifter thing.

Steve

Re: Question about BB 4speed crossmember
 

[ QUOTE ]
Oh, I got you, the Muncie shifter thing.

Steve

[/ QUOTE ]

Yep. Most, if not all the "Bolt to the x member shifters" got one. Ditto for Chevelle and Nova although they are different from Camaro.

The repops on the market are generic and may or may not fit a particular application.