1969 Z28 Cross Ram Help???

[Als 70 L78 Nova]

I picked up around 70 intakes and 50 carbs today and one was a cross ram I thought. The casting numbers are right and they look to be original. Here is the problem. The top does not match up to the bottom. The top is a 3941130 with a casting date of 8-20-69 and 3/8" holes. The bottom is 3941126 with a casting date of 11-25-68 and 1/4" holes. What gives? Any help would be appreciated.
Al in Maine
http://img.photobucket.com/albums/v295/dillon14/xram/DSCN1798_zpsdc68ab38.jpg (http://smg.photobucket.com/user/dillon14/media/xram/DSCN1798_zpsdc68ab38.jpg.html)
http://img.photobucket.com/albums/v295/dillon14/xram/DSCN1797_zps189ba13f.jpg (http://smg.photobucket.com/user/dillon14/media/xram/DSCN1797_zps189ba13f.jpg.html)
http://img.photobucket.com/albums/v295/dillon14/xram/DSCN1796_zps5493b43f.jpg (http://smg.photobucket.com/user/dillon14/media/xram/DSCN1796_zps5493b43f.jpg.html)
http://img.photobucket.com/albums/v295/dillon14/xram/DSCN1795_zps0170e8b5.jpg (http://smg.photobucket.com/user/dillon14/media/xram/DSCN1795_zps0170e8b5.jpg.html)
http://img.photobucket.com/albums/v295/dillon14/xram/DSCN1794_zps28a47d87.jpg (http://smg.photobucket.com/user/dillon14/media/xram/DSCN1794_zps28a47d87.jpg.html)
http://img.photobucket.com/albums/v295/dillon14/xram/DSCN1793_zps2bfcabeb.jpg (http://smg.photobucket.com/user/dillon14/media/xram/DSCN1793_zps2bfcabeb.jpg.html)
http://img.photobucket.com/albums/v295/dillon14/xram/DSCN1791_zps67c8c94c.jpg (http://smg.photobucket.com/user/dillon14/media/xram/DSCN1791_zps67c8c94c.jpg.html)
http://img.photobucket.com/albums/v295/dillon14/xram/DSCN1789_zps690f381f.jpg (http://smg.photobucket.com/user/dillon14/media/xram/DSCN1789_zps690f381f.jpg.html)
http://img.photobucket.com/albums/v295/dillon14/xram/DSCN1788_zpscdd7892c.jpg (http://smg.photobucket.com/user/dillon14/media/xram/DSCN1788_zpscdd7892c.jpg.html)

[DW31S]

Is it the way you have the top positioned, or does it NOT match the bottom? I'm wondering if the earlier of the two is/was cast during the developmental stages of production. Try Jerry MacNeish, or one of his books. I know John Hooper's books covered crossrams, but I do not have any contact info. for him. Last I heard he was in DE and had a new ZL1 stolen from a new car dealership.

[Als 70 L78 Nova]

The holes do not line up regardless of how it is turned and the hole sizes are different.

[Kurt S]

http://www.camaros.net/forums/showthread.php?t=273337

Why not wait to see the answers from one forum first?

[Als 70 L78 Nova]

I am a little surprised that posting a question on two forums would bother you. Just saying.

[67 Nova Boy]

They might be the reproductions maybe? I have seen the tops on eBay that the

seller says they won't fit their bottoms and seem to be GM or repo's. The top

may fit the bottom of an Offenhauser.

Dave
67 Nova Boy

[Kurt S]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Als 70 L78 Nova</div><div class="ubbcode-body">I am a little surprised that posting a question on two forums would bother you. Just saying. </div></div>
I often have to dig out research info and type up a reply.
I get frustrated when I find out there's already an answer posted in another forum. It's a waste of my time.

[Als 70 L78 Nova]

My apologies to you.

[Lynn]

I had a GM cross ram top years ago, and can say with certainty that it did not fit the Offy or the Edelbrock bottom.

So.... are you saying the reproduction cross ram isn't the same bolt pattern as the GM? That would seem a major goof.

Also, don't the repros all have the same casting date? Anyone know that date?

[iluv69s]

First of all, the repo tops fit the GM bottoms. Second, the early prototype intakes all bolt up with the later tops and bottoms. The changes were minor once they started the 'production' intakes.

The bottom does not look GM to me off the top of my head. I see no bosses for the oil sheild mounting points that the early units had. These bosses were on all the intakes even though they cancelled the oil sheild. The top looks like a repo also. It is difficult from pics because the repos are pretty good. If you can post some closeups of the edges of the intake top and also the mating surface where the top mates to the bottom, I can tell you definitively. The machining marks are a giveaway between the new repros and the originals.
I can pull out one of my original intakes to compare. I also have an offy intake that ill look at to compare. I would bet that you have an Offy base..and a repo top.

[camaromb]

Repro crossram, missing lots of the details that original ones have.

[Tracker1]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: iluv69s</div><div class="ubbcode-body">First of all, the repo tops fit the GM bottoms. Second, the early prototype intakes all bolt up with the later tops and bottoms. The changes were minor once they started the 'production' intakes.

I would bet that you have an Offy base..and a repo top.

</div></div>

I'll take your money <<GRAEMLIN_URL>>/smile.gif - an Offy base with a winters foundry marking and a GM casting #? Nope.

[Stefano]

I believe the Offenhouser has one less bolt securing the top to the base while the Edelbrock is a match to the GM X-Ram.

[iluv69s]

With all due respect, welders can do amazing things nowadays. Check Jerry M's sight
and you will see pics of the original block from my Zl-1 that had the snowflake ground off and 'put back on' by melting a piston and making a plug w the snowflake using another original block to make a mold. Than a hole was made using a holesaw and the plug welded back in... After a reskinning of the whole block the repair is unoticable.

I did pull out an original xram and a new offy unit that i had for years and took a look. I am 99.99% sure this base in question is not a GM base..nor a repro.. ( I also have a repo unit I bought a while back) ..

I am 99.5% sure it is an Offy base .. When compared w the pics of the base in question, the similarities are obvious compared to a GM unit.. Im traveling to brazil tomorrow, but i'll try to post a few pics...

Also the repo units are actually very detailed and excellent copies that are almost undistinguishable to an original..

Still wanna bet?? Just kidding !!

Max

[iluv69s]

..

[iluv69s]

Forgot... The top plate..without better pics or seeing in person , Id say 90% repo to 10% GM based on what I can see from these pics.

Just my opinions...

[iluv69s]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Stefano</div><div class="ubbcode-body">I believe the Offenhouser has one less bolt securing the top to the base while the Edelbrock is a match to the GM X-Ram. </div></div>

Actually 2 less bolts

[Tracker1]

Ok I will send you a dozen Canadian beer in the mail <<GRAEMLIN_URL>>/beers.gif

they will be real - not re-pops like this cross-ram <<GRAEMLIN_URL>>/smile.gif

[Als 70 L78 Nova]

OK, I found out that the top and bottom are both re-pops. Bitten again.
Thanks for all of the comments.
Al in Maine