Cylinder 6 exhaust manifold bolt clearance issue

[CV355]

The lower exhaust manifold bolt on cylinder 6 will not clear the shock tower enough to be installed.  Short of raising the engine or drilling out an access hole in the shock tower, does anyone have any quick fixes for this that I may not have considered?  The bolt is about 1/4" too long, and I'm afraid cutting it to fit will not give enough thread engagement in the head.  The head of the bolt strikes the relieved area of the shock tower reinforcement plate.  It was a tight fit before with the CJ heads, but the Trick Flow heads and TMC motor mounts seemed to have repositioned the engine just enough to make this a problem.  Really wishing I had know this could be an issue beforehand and I would have popped the bolt in before the engine was installed (primary is slotted for this one bolt)

Any ideas?  This looks like the last hurdle for now.  This is on a '69 Mach 1 428 car.

[cjshaker]

Raise the engine on that side. All you have to do is remove the main bolt holding the upper and lower together, then jack the engine up a bit on that side.

After it's installed, you might find that the bolt still contacts the brace. I had that issue with Medium Riser heads in my R code. I beat the brace back (using heat) when I had the car on a rotisserie, but it still contacted the brace when the engine was installed. The "pecking" against the brace at idle drove me nuts, so I made a tie bar that goes from the head to the sway bar mount, to stop the vibration that caused the pecking. It worked.

[CV355]

Raise the engine on that side. All you have to do is remove the main bolt holding the upper and lower together, then jack the engine up a bit on that side.

After it's installed, you might find that the bolt still contacts the brace. I had that issue with Medium Riser heads in my R code. I beat the brace back (using heat) when I had the car on a rotisserie, but it still contacted the brace when the engine was installed. The "pecking" against the brace at idle drove me nuts, so I made a tie bar that goes from the head to the sway bar mount, to stop the vibration that caused the pecking. It worked.

I was afraid it would come to that, but it is the most logical way to approach it.  Where would the safest spot be to raise the engine?  Rear trans mount boss?

I think I'll be ok without the bolt head pecking though it is very close.  The TMC mounts are as close to solids as you can get without being truly "solid."  Plus I have 1/16" clearance between the valve cover and the master cylinder reservoir.  That's a big engine... 

[cjshaker]

The rear trans mount boss would work, although I'd think the headers may get in the way of doing it that way. I usually just use the hoist, but I've used a jack and 2x4 under the pan also, just being careful not to push the pan sump up.

[cammerfe]

Put a piece of 2X4 endwise against the front lip of the pan and use a hydraulic jack to raise it. Then there's no chance of smashing in the pan sump.

KS

[427mach1]

Doug, I've always heard it's a bad idea to mix solid motor mounts with rubber (non-solid) motor mounts.  Putting a solid tie bar is essentially adding a solid motor mount.  Have you experienced any problems, such as cracked bellhousings or...?   

From Summit Racing:

Pritts says Summit Racing does not recommend mixing and matching motor mounts either.

“If solid mounts will be used, they should be used in all locations,” he said. “If one mount is flexible and the others are not, this flex point may cause broken parts such as a bellhousing. Again, we recommend solid mounts for race apps only!”

[GerryP]

Doug, I've always heard it's a bad idea to mix solid motor mounts with rubber (non-solid) motor mounts.  Putting a solid tie bar is essentially adding a solid motor mount.  Have you experienced any problems, such as cracked bellhousings or...?   

I agree.  I use a chain or cable just as a failsafe should the mount break.  Nothing fancy.

[cjshaker]

Doug, I've always heard it's a bad idea to mix solid motor mounts with rubber (non-solid) motor mounts.  Putting a solid tie bar is essentially adding a solid motor mount.  Have you experienced any problems, such as cracked bellhousings or...?   

From Summit Racing:

Pritts says Summit Racing does not recommend mixing and matching motor mounts either.

“If solid mounts will be used, they should be used in all locations,” he said. “If one mount is flexible and the others are not, this flex point may cause broken parts such as a bellhousing. Again, we recommend solid mounts for race apps only!”

I haven't had any issues, but then it's only been raced a couple of years this way. I have a Lakewood bell, so not sure how easily a crack would form there (I've never seen a steel bell crack unless it was something drastic). I do have a set of poly mounts to use on the engine and trans when the new engine goes in.

[Heo]

A setup that will crack a bell is with solid motor mounts/front motor plate
and solid transmount. Need to have rubber transmount to compensate for
chassi flex.
Like Doug have it i dont se any problems