I broke my original 67 exhaust manifold and could not find a 67 to replace it with so I purchased a 71 manifold and I'm not sure if it will fit. After wrestling with it for 45 minutes I got it kind of in place going in from below but there is some kind of mount on the back of the block that seems to interfere with the #7 runner, it seems to keep if from going back far enough. I thought all the Big Block Buick's were petty much the same on the outside. I'm not sure because darkness put a end to my endeavor so I really haven't got a good look at the obstruction. While I sit all night stewing on this problem I was hoping some one might be able to shed some light on my predicament. Has any one tried to put a late model exhaust manifold on a 67 GS400 and what was the outcome? Thanks
Ya sorry about that I was trying to change the font and wound out only posting the title, looked kind of lame I know. I was hoping I could finish the post before any one noticed.
We did this 20+ years ago to my '67 when the original '67 manifold on the drivers side cracked. We raplaced it with a later version and if my memory serves me correctly, we had the same issue and had to trim one of the "ears" from the block. More specifically it was the ear on the drivers side near te #7 cylinder as you described. That original engine is now out of the car and stored on a stand so I'll try to look tomorrow and see if that ear has indeed been removed, that will verify what I remember (it was a long time ago).
I did? That question was about the heat shield and the efficiency of the 67 manifolds and if you read on I mentioned that I haven't event tried to see if the manifold fit yet. Well I now am at the point of checking for correct fit and am having difficulties so I asked the question here. I'm not trying to flood the board with duplicate questions just asking questions as the come up.
Whoa, LOL. I didn't accuse you of anything. The heat shield is for the pre heat hose that goes from the exhaust manifold stove up to the air cleaner. Pre heats the air so the carburetor can run on leaner mixtures in cold weather. You don't have to use it. The 400-430-455 are basically the same engine with different bore sizes. All the exhaust manifolds should interchange from any of those engines. Some early engines used a heat riser valve. The threads are similar enough that I thought you were asking the same thing.
Thanks Gary I kind of figured you would have ran into this problem some where along the line. It does look like that ear needs to go or I have to look for the right year manifold, yet another fun thing about having a rare car 1 year only exhaust manifold I'm sure there all over the place.:laugh: Like I said I ran out of day light so I haven't a clue what that ear is for but it too must be a 67 only thing. I appreciate the help. Thanks ---------- Post added at 09:31 PM ---------- Previous post was at 09:27 PM ---------- No problem I didn't mean to come across harsh or anything, sorry if I did. Thanks for the information I could not for the life of me see what that shield was protecting on that side of the block. Good to know. Thanks
Here is a photo of the original engine to my '67. Notice the two areas that are circled in yellow. The rear had an ear like the front, but it had to be removed in order to get the later model manifold to fit.
I just happen to have a 455 block on my engine stand with a set of 67 heads and 67 exhaust manifolds bolted up to it. there is no interference between the manifolds and the lugs on the block although it is close on the front lug.
If you compare your photo to mine it's easy to see that the rear ear or lug is much farther forward on the '67 block than it is on the 455 block. Look at it's location in relation the the #7 exhaust port, it's in front of #7 on the '67 and behind the exhaust port on the 455. So that explains why a '67 manifold will work on a later block with no interference, but a later exhaust manifold will not work on the early block unless the ear is removed. Another oddball thing about these darn '67s.
Thanks for responses guy's, it's hard to figure out why they would move that ear after 67 I guess thats the joy of having a firs year motor. It looks like you ground the tab off with no problems Gary but I don't know if I can pull that off with the motor still in the car. I may have to hope I can braze my old one or some one has one that they don't need. I always wondered why the 67's manifold's are different I guess now I know, next time I think I'll be more careful but thats not really my style.
