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Discussion Starter #1
Getting ready to pull the 400 out of my '67 LeMans. It's equipped with long-tube headers and all looks awfully tight in there. There's no way the engine is coming out with the headers in place, but they don't look like they can drop out from underneath, either.

It would appear the headers will need to be unbolted, then left in place, while the motor is lifted away from them. And in return, reinstallation will be the reverse, with the headers already sitting in place inside the engine bay, and the motor lowered down on top of them.

Can anyone confirm this as the correct (only?) procedure?
 

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You got it (they can be done with motor in but since your taking it out anyways, thats the easiest way)....spray those bolts down with break free real good and let it set before trying to loosen them. You may even want to lift the motor as much as you can to get more working room to remove the bolts. Headers are the most frustrating part on Pontiac motors as the bolts go in upwards at an angle with little to no clearance on the back middle bolts. You may need to take a long open end and heat and bend the shaft to get the angle right just to get 1/8 th turn at a time on a few of them with the motor in the mounts. The best manifolds are the Ram Air reproductions as the have more clearance than headers and are nearly as efficient. Also drain the trans and unbolt it and cross member from below makes life a lot easier especially if you don't have a few helpers, throw everything you have learned about small block chevy's out the window...you own a Pontiac now....:D
 

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:agree When I installed the headers on my 69 they came with specific instructions. Good thing too, because without them I would have never gotten them installed. It involved removing one motor mount bolt, lifting that side of the engine with a jack to create clearance, then dropping that header in from the top. Passenger side first as I recall, then reinstalling that bolt and repeating the process on the other side.

When the time finally comes for me to service the lower control arm bushings on the passenger side, that header is going to have to come out first. Otherwise it will be impossible to remove the rear-most lower control arm bolt.

The "next time" I have to loosen them for any reason, I'm going to be "smart" and replace at least the end bolts with studs. Trying to get those header bolts started, especially the rear ones, while diving head first into the engine compartment and trying to line up the header with the bolt hole AND the header gasket while "blind" caused me to greatly expand my vocabulary. :D

Bear
 

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Discussion Starter #4
Very helpful and much-appreciated information, guys. Even performing header installation on the little 289 in my husband's Mustang was a challenge. I guess we will just give the Pontiac's setup our best shot. Will keep you all posted.
 

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You know you can buy ram air exhaust manifolds that fit much better, and flow damn near as good. Good option unless you are trying to squeeze out ever last 1/100th of a second.
 

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X2 on the HO or ram air manifolds. They don't ever leak, either. That said, what the other guys said. One thing that always helped me install headers with the engine in the car was to jack the front end of the car waaaay up so that you can tilt the header and feed it in without the flange hitting the ground as you're doing so. With the engine going back in, you may want to start all of the header bolts before you lower the engine home into the mounts. Use a block of wood between the engine and cross member as a safety stop, and watch your hands. Good luck.
 

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Reb, you will find that even though it's a LeMans most parts you will be buying are GTO parts and with that three letter moniker attached they will be priced at a premium over the more abundant and popular ford and chevy parts. The RA manifolds will set you back around 400.00 dollars.
 
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