Having a header interference issues and hope someone has theirs apart enough to check this.

Car is '68 Cutlass w/orig 350.

I'm looking for the location of the block relative to the front cross member's back side.

Here's a pic of mine...

clicky for big...

The pink line is what I'm referring to. On mine it looks like the back surface of the x-member on the left side lines up about 1/3 of the way thru the #5 plug. The pink line is plumbed from the plug to where it just touches the x-member (the x-member face is not straight/vertical/flat - close, but not exact).

My header collector is hitting the back side of the x-member. Others have said with these headers there should be ~ 1/2" clearance.

I've moved the engine back as far as I can (loosened all block, frame & trans mounts), but can only eek out maybe 1/32" collector clearance. Everything else like clutch linkage,etc.. lines up perfectly. Right side header has 1+" clearance.

Any ideas, pics, measurements, or comments are appreciated!

 

are the motor mounts new ?

 

Yes. Anchor 2261

I compared them to each other prior install and there were almost exactly the same, so I don't think swapping them will make any difference. And, the trans mount is ~1/8" from being all the way back, so even if I can shove the engine back more, I run out room on the trans mount.

I've talked to the header mfgr. Their position is that the x-member is too far back and/or the engine is too far forward.

So, I was hoping for other's cars for comparison....

 

Are both headers straight at the collectors? I know with some of the header manufacturers people were getting issues such as yours. What brand are you using? Can it be dimpled, which is a common practice for header installs? can you put a spacer between the motor mount and the block? Perhaps call the vendor and see what they say.

 

Yep.




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I'm not sure how putting spacers 'tween the block & mount would change things. Seems like that would just lift the motor a bit.

I'm not sure about dimpling as you would have to 'crush' part of the collector right at the weld. The collector is the only thing hitting. The collector flange has ~ 1/8+" clearance and is free to move.

Mfgr has the header now (it had other issues besides clearance) and was supposed to 'jig' it to check, but no feedback yet. I'm trying to figure out if my car is weirdly built or is the same as others in preparation for their response.

I'm puzzled as to why the right side has more than 1" clearance to x-member, but left is too tight. I understand the head offset, but I'd think they'd make the headers accordingly. There's plenty of room to move the left side collector back...at least an inch.

 

I’ve had this same issue several times on 68-72 A bodies with the shorty’s and large diameter primaries. The car looks to be apart? If so here’s how I fixed it. I’ve notched the cross member in that area in several cars. I carefully measure, cut then weld in a sliced section of steel pipe. Size depends on the header. Once finish ground & painted it looks good. If done right it won’t affect structural integrity of the frame. You don’t need but about a 1/4 of a pipe, I think the last one I did on a shorty was 2” or 2.5" pipe. I started with slicing it in half then shaved it down from there so it’s a very unobtrusive concave spot in the frame. Only a well trained eye will catch it. Others have simply cut and laid back that area then welded in angled pieces of flat stock. That works too I just think the pipe looks cleaner.
I’ve seen others simply heat & beat that area on both sides but I like to do it right.

 

What make are those headers? They look odd to me, like G body shorties or something.
I would modify the crossmember. I don't think your car is crooked, the shorties are just a goofy setup.

 

I was going to keep the mfgr out of this for now, but WTH...

Sanderson O351's

Modding the x-member is very problematic for me. I don't have the skills or tools to do it, don't really want to alter the frame, and the chassis is kinda immovable at this time. For what I'd spend to get it done, I probably could have got those beautiful ARH long tubes.

That's why I was trying to figure out if the header itself was off (which seems likely to me because the right side has so much clearance & there were some other issues with this one) or if my car was off.

 

OK..for the Friday crew...!

Does anyone have theirs apart enough to check the block to x-member position like in the first post?

Still trying to figure out what the variance in these cars is...

TIA!

 

I don't know if this will help you, but atleast I tried.

I cannot see my driver's side due to the plug wires, steering shaft and etc in the way. These are pictures from my passenger's side or even number bank. I know heads are not in the same postion left to right but you could compare the passenger's sides. Your engine should be parallel in the frame so left side positioning should be same as right, just you reference of the sparkplug well will be different. You will need to compare your right to my right.

I have a 1968 Cutlass S holiday coupe.

originally.... 350cid, 2 speed auto, single exhaust.
now a '76 350 cid (it's a 395558 2), 350th, true dual with long tube headers.

I have new ~2 years, 2261 Anchor engine mounts. I don't know about the tranny mount or rear cross member, they are as they were when I bought the car in 1998. Anyhow....

Here is my passenger side cross member/engine position.





I hope this gives some help. Let me know if a different angle will be any better.

Adam

 

Adam, Thanks for taking the time to get & post those pics!

Here's the pass. side on mine....


clicky for big...

The pic makes it look like my plumb line is curved, but its straight vertically (thin piece 'o duct tape with a bolt at the end).

My engine location looks pretty close to yours, although mine may be a bit further back....but then again, I loosened everything and shoved it back as far as I could.

Oh, and "2861 Anchor engine mounts" ?? Is that a typo ? Those check out to Ford Croen Vic mts...and the 2261s are the only (68-72 A body) SBOs I know of...

 

I don't mind helping if I can. I have gotten lots of good info from here. Yes the 2861 was a typo - I changed it in the original post to not confuse anyone.

Adam

 

Hmm, my Sanderson's fit fine on my G body with the 78 403 B body mounts. I got 3 good sets, another member got three bad sets. A grinder on the cross member will fix that minor touching.

 

Thought I'd update this since I got the headers back from Sanderson and they're now installed...

After..


I'm not sure how they did it, but there's now a good 1/4+" of clearance. I do see some very, very minor deformation of the two front tubes, but not enough (IMO) to account for all of the change.

Overall, everything appears to have been fixed/recoated as needed and they fit and look good now....

 

Motor mount frame pads in the wrong set of holes???

 

There's only one set of holes to use....and everything except the headers (Z-bar, trans mount, etc..) lines up perfectly....