I have a 69 Cutlass with a 455 and AC. I have removed the exhaust manifolds as well as the oil filter and housing. i have not attempted to install the headers yet but figured I would ask if it is best to do from below or above as well as if there is anything else I should remove to make access easier. I'm thinking from below due to the AC compressor being in the way, but that could be removed as there is no freon in the system at the moment. The wheels are off and Its up on jack stands. Any other tricks?

thanks,
Steve

 

From below is really your only choice. Get car as high as you can in the front.

Be prepared to remove the long engine mount bolt on the side where you’re working and loosen the other side. On the installation side you may very well need to jack the engine up to make room for the header to get into the gap. I prefer to jack the oil pan rail using a length of 2x4 as opposed to the bottom of pan. engine will swivel off the remaining mount bolt. You can remove both sides & jack the whole engine as well. When jacking, keep tabs on bell housing to tunnel, distributor, opposite side valve cover, fan/shroud, etc so you don’t have any unintended adjacent damage.
If the engine is too high to catch a bolt or two on the flange, lower it a little, very carefully, so you don’t damage a tube if it’s against a control arm edge or stud. If encountering potential interference, don’t smack any tubes until the engine is back on the mount, header against flange and interference confirmed. (been there & done that)

Take your time and keep checking things as you go along. You will 98% have to drop/remove starter on the left, clutch/trans linkage and brake distribution block TBD.

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thanks, that's a good start for me to have a better idea what I'm in for. I was planning on changing the motor mounts anyway so now is a good time.
Steve

 

If you need/plan to replace the mounts, this is a good time. I have a '68 4-4-2 in which I added Hooker 3902 headers. These headers' end bolt mounting points are slots, rather than holes. My understanding is that the 400 block is the same as the 455 block in this dimension. I had to drop the starter, but the oil filter adapter did not need to come off, just the filter, and that was just for wiggle room - it would fit and go into position with the filter in place, but the extra room makes it easier to finagle into position. After deinstall of the exhaust manifolds, replace the rear bolt into the head but don't tighten it down. This way, upon installing the header from below, you can slide the header's bolt "slot" onto the bolt, thus temporarily hanging the header in place until you get back above and install the other four bolts (each side).

The hardest part is tightening the rear bolt on the AC side. Doable, but a PITA, resulting in bloody knuckles.

 

If you remove the starter and oil filter housing, the headers will go in with the engine on the frame mounts. You need to get the front end of the car pretty high. I have had solid mounts on my car for probably 20 years, rubber mounts might change things.

You really need to relocate the brake distribution block. The header will cook the valve and fluid. Some people just remove it and install a later model design up by the master cylinder. I repositioned mine on top of the frame, using one of the threaded holes for the clutch pivot, and drilling/tapping the other hole.

 

Thanks Guys, your experience has been great help. I got the PS header in and will move on the the DS. I was struggling to get it in, thinking "no way this will fit" when it occurred to me to jack the front up higher and, what a relief, it fit easily.

Steve

 

There is one bolt that I don't believe can possibly be installed. Will that be an issue or am I missing something. The tube is just in the way. It is the same for both sides.
thanks

 

If a bolt will not go through the hole with the header on the bench, you need to install a stud in the head that will allow a nut to be used instead.

 

OH Boy, I hadn't noticed the problem until I had one on. Well I guess it will be coming back off. That certainly sounds like the right solution. At least there is only one on!!
thanks

 

What headers did you get? I would be interested to hear how they fit when you are done.

 

I will post the results when I'm done as well as what ones I purchased.

Steve

 

Are they the beat chinesium?
I’m not mocking…they look nice. And if using a stud on one hole is the only concern that’s great.
You can also cut the bolt a bit if that helps.
-Peter

 

That situation is common on Olds headers, as stated above, use a stud, find (and/or adjust) a length that won’t gouge the tube when things are tightened. Start bolts in the front and back holes to support the weight of the header. You then have to sort of “hover” the header off the head so there’s juuussst enough room get the nut (that your already holding against the flange) started on the one or two threads you expose. Once you go through the digital gymnastics of starting the threads, the nut can be spun on, a thread or two at a time, with fingers, a pocket screwdriver or an open end wrench. A small magnetic pickup tool can also be a boon when starting the nut or positioned as a “catcher” if the nut tries to escape.

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You can put a bolt in that spot, if you know the trick.

Install the 2 end bolts loosely, so the headers isn’t right up against the block. Slip the bolt into position, it will thread in.

It helps to have a few cheap wrenches to can bend and modify for these projects. Good luck.

 

^^^^ This! ^^^^^ Though I did not have to bend any wrenches with my Hooker 3902's.

 

Well I checked and the flange is 3/8" thick and with a little grinding so I could angle the bolt in the longest I could possibly get in is 3/4" that would give me 3/8" of thread into the head. Seems like not much but any thoughts as to if that is adequate? Or I'll pick up some studs and pull the header. It's always easier the 2nd time doing something.

Steve

 

3/8" into the head doesn't sound like enough, especially when to take your gasket thickness off of that. You need to remove the header and get it out of your way.

I would find a stainless bolt with at least 2 inches of thread and install it into the hole using red locktite. Using a bolt allows you to torque it tight. Then cut the bolt off with a cutoff wheel leaving about an inch of threads sticking out of the head.

Now you have an installed "stud" that is the correct length and will not back out on you later.

tc

 

An inch of threads sticking out will be too long. It will bump against the inside of that tube and prevent the flange from mating with the head. It is tight quarters in that nook/cranny!

 

What I do, is I oblong that hole, then put the header on, and start that bolt first, then make it tight enought, to where you can still slide it back. Ones the bolts all the way in you can put the rest of the bolts in, and the you should be able to put a wrench on it to tighten. I also slot the gaskets, so when the bolts are on, you can slip them on place . makes it easier than trying to put bolt, headers, and gaskets on at the same time.

 

What I do, is I oblong that hole, then put the header on, and start that bolt first, then make it tight enought, to where you can still slide it back. Ones the bolts all the way in you can put the rest of the bolts in, and the you should be able to put a wrench on it to tighten. I also slot the gaskets, so when the bolts are on, you can slip them on place . makes it easier than trying to put bolt, headers, and gaskets on at the same time.

 

Exactly. I heated up and bent wrenches as needed.

 

By all means cut it off where you need too. With a 3/8 flange plus a gasket, you would have about 9/16" of the stud poking through the header flange. If a 3/4" bolt will go in the hole as is, I was making a SWAG on the stud length that would work.

 

Header bolts are 3/8 diameter. I believed the rule of thumb is you need at least the same thread engagement as thread diameter. Think about the thickness of a 3/8 nut, as long as you have similar thread engagement in the head I would think your good. Besides, these are headers. If you crank the bolts tight enough to pull the threads from the head, you will have already distorted the header long before. Headers aren’t structural, as long as they are tight enough not to leak, and tight enough not to come loose your good

 

Interesting whats comes out of picking the brains of a group, A lot of good ideas. There should be a place for "Things to know before you install your Headers" on the forum.
thanks to all, I'll be back at it later today or tomorrow.

Steve

 

There are hundreds of threads that you can read if you do a simple search about headers.

 

I did search on this site but didn't see anything addressing installation. I'm sure if I sifted through all the related threads something would have come up. So ath this point I will remove the PS header and start over with it. I did use a 3/8" drill and elongate the hole on the DS and a good size bolt fits through. I will have to screw it in holding the header out. But fiest i wanted to change the motor mount. Easy enough right, wrong. Someone had overtightened in and bent the ears in so it wouldn't slide out. About 2 hours later and 100 trips over and under it was out. The mount was shot. A prior mechanic had told me they were fine. I guess he didn't see the back side. I proceeded to wiggle the header in from below and hook it on the rear bolt. After struggling a bit I went to look from the top and the obvious problem was the oil dipstick tube. I have done enough damage while trying to fix things that I figured I would ask how to get it out. I assume it is just pushed in and turning it and pulling will eventually get it out. After that I will see if it clears the shift linkage. Someone did mention removing it. I have a column gear selector. again, thanks to all of you for your help. having done exhaust manifolds before I figured I was capable but there was more to it in this case.