Gentlemen,

Car: 69 SS396 convertible
Issue: Stock exhaust manifold clearance at the steering gear.

Question: How much clearance should there be? I had to take off the top plate of the gear box to install the stock manifold. This is a total restoration and I had removed the steering gear box earlier and did not install it prior to putting the engine in. I removed the exhaust manifold to install the gear box, then had to remove the gear box cover to install the manifold. Now I cannot get the cover back on. Is this normal? I believe the engine mounts and frame mounts are correct for the Big Block (it is a true BB, SS car) and I am doing everything I can to keep it as close to original as possible.


Thanks in advance.

Doug

Doug

I'm not sure you should have removed the top plate for the steering box unless you know what you are doing. Check into it, but a steering box malfunction can be disasterous to a restoration, not to mention someones life. There should be 1/2" or so clearance between the manifold and gear box once installed. Next time, pull the long motor mount bolt out of the mount, jack the motor up on the drivers side, and hold the manifold in place while someone CAREFULLY lowers the engine back onto the mount. Just make sure to ask someone knowledgable about steering boxes before you proceed.

Can you see that the engine is offset ? Take a tape measure and measure from the air cleaner stud to the side of car (or frame). I'm betting you do not have big block frame stands.

Thanks for the replies!

I don't like the idea of having the wrong mounts. However, this seems too close to fit. What are the measurements of the mounts or the offset so that I can check these? What would be the best location on the engine/trans to jack up the engine to either, replace the mounts or fit in the steering gear? I think I will remove the gear and have it rebuilt now that I have probably screwed it up. Sorry for the dumb questions but I have spent several years getting to this point and I don't want to have to remove parts and I certainly want to do it right. I used a chain pull to put the engine in. Now everthing is painted and aligned so I prefer to not remove the hood.

Thanks again in advance.,

Doug

The offset is approximately 1". This can usually be visually seen. You can also look at the harmonic balancer to see if it is offset from the center of the crossmember.

Thanks, I will check this tonight.

I checked the offset and it measures at about 1". I took several measurements and it seemed consistant. I could actually see that the engine sits to the P-side slightly judging by the center brace on the subframe vs. the harmonic balancer bolt. Therefore, I am suspicious of the steering gear. The numbers on the gear box are 7806688 front cover (small #'s) and 5691676 on the box with a small 243 under it. Could this be the problem and this gear box is slightly wider/taller???? I want to make sure that I eliminate all the possibilities before starting to change or replace things.

Thanks very much for any help.

Doug

Wow, And I thought you would find the wrong mounts. It sounds like you do have the correct mounts ! You do not have new heads, with the raised exhaust ports do you ?
Those numbers on the box are just for that part of the box. Not the complete assembly. I have heard that all 800 series boxes are the same size.

Tj, what do I do now??? The heads are stock heads. I did not change or modify anything. I have been trying to get this thing as close to original as possible. This has rapidly turned into a "I'm stumped". I don't think the steering gear was on the car when I purchased it years ago. Please let me know if there is anything here that I am overlooking.

Thanks again,

Doug

20 years ago i did a top in a chrysler.because line was frozen to it. when i put it back on. instantly it turned to left. my arm was threw the steering wheel almost took it off.i dont know about gm i never took another 1 off. may want to ask a gearbox rebuilder on gm. dont put arm in steering wheel to start it.

I'm not sure, what you should do. I would probably raise the engine as much as you can, without taking it all apart. (unbolt the engine mounts etc.) Install steering gear box, install exhaust manifold, and lower engine ? I'm stumped also, as to the cure.

I assume you have a power steering gearbox (they're longer than a manual box). I also assume the car is on jack stands at all 4 points. The left (driver) side exhaust manifold can be installed from the bottom with the engine raised about 2" or so off of the mount. You also need to disconnect the exhaust pipes on both sides and loosen up the attachment points at the muffler to allow the exhaust system to lower slightly so as to gain enough room to do this (this presumes an H or X pipe connection). IIRC you may have to disconnect the E-brake cable also. I've done this many times and it seemed like it would never fit but it always did. With everything installed there is about 1/4" - 1/2" (more?) of clearance between the manifold and the steering box. I now have headers on the car so it's been awhile but I did have exhaust manifolds on for years. Hope this helps.

Do you have the right engine mounts? Sounds like your frame mounts are correct. Maybe the actual engine mounts are wrong?

Thank Jim and Brian,

I took another look at it this weekend and there appears to be about 1/4" to 3/8" of clearance. I just thought that was too close. If that is ok, then I plan to remove the box and have it rebuilt (since someone said that I should not have removed the cover), and then reinstall by jacking the engine up, etc. as you recommended.

Thanks very much for all the help.

Doug

I ran a BB in my 69 for years with the small block frame mounts and exhaust manifolds. When I pulled the motor the last time, I could see where the manifold ever so slightly was rubbing the steering box. With the BB mounts sitting the motor 3/4"-1" to the passenger side, I'd think you should have that much clearance. Good luck!!

I haven't read this all through but would like to comment that our old car's BB drivers side exhaust manifold has a dent in it to clear the box.

You might have one's off another car that doesn't need/have the dent??

Possibly a later 454 P/U?? I'd have to look at the one's I took off my '75 454 P/U engine to tell??

Just throwing this out and right about the BB frame, BB cross member and the BB rubber mounts.. (BB's are offset to the pass. side by about an inch!)..

I did use my SB cross member by kicking the tranny tail over the needed inch and then using a 3-hole poly tranny mount by installing one bolt through the pass. side C/M hole and into the center poly bolt hole. Works fine!! BUT not stock..

And fwiw, years ago, I installed a hopped up 409 "W" engine in my car right on ALL of my 350 stuff, M-20 stick car!

Sucker looked like it came frome the factory! 2.5" dia., cast-iron exhaust manifolds.

pdq67