Exhaust Manifold Help

[Ricko1966]

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[75gmck25]

Several of the Vintage Air brackets appear to be the same design as various Alan Grove brackets.

I used Alan Grove brackets with my stock iron manifolds when I mounted a Sanden compressor, and then later switched to a different Alan Grove bracket (which had spacers to allow for the difference in manifold vs header flange) when I installed headers.

IIRC, I took the piece for the PS bracket and cut off some extra material, and reused it with the new Alan Grove brackets. My truck is currently sitting in a snow bank, but I may be able to get a picture of the brackets in the next day or two. My original PS brackets are not the same as yours, maybe because I also had the big A6 compressor on that side.

 

[Old Guy Bill]

Awesome. Thanks for that info. Any chance you could snap a pic of that Vintage Air bracket? I’m not sure how close it is to the OEM bracket. This is the OEM bracket:

The factory AC brackets were long gone from my truck, I was replacing it with VA anyway.
You will probably have to add washers or grind/fab a spacer... but that's a requirement with vehicles this old.

 

[Sad Sack]

I've had good luck on headers using FelPro 9275 B gaskets with blue Loctite on bolts or header bolt lock washers.

 

[fast 99]

spreader

if the manifolds are excessively warped manifold holes could be out of alignment. May need to enlarge the outer holes. Cast is tricky to drill, I have a reamer for this application. Also helps if they are heated a little. Off-shore replacement manifolds are junk, stay away.

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[DoubleDingo]

They typically pull together, rather than spread apart. You can buy a specific spreader tool to use while installing, to get the bolt holes lined up.

At any rate, it's likely not the issue in this case, since the manifolds have already been removed and installed a couple times.

I install the spreaders before unbolting, that way the holes don't change position from the manifold pulling them together. Makes it easier than installing the spreader after the fact, then finding the right spot for 4 bolts to get started and then spread the other side to install the other two bolts.

 

[PEARTHBOUND]

HI,CHECK YOUR EXHAUST PIPES FOR LOOSENESS,YOU KNOW HOW A TEETER/TOTTER WORKS SAME PRINCIPLE INVOLVED

 

[idahovette]

^^^^^^^DON'T YELL WE CAN HEAR^^^^^^^^^^^^^

 

[Bextreme04]

^^^^^^^DON'T YELL WE CAN HEAR^^^^^^^^^^^^^

WHAT!?!?!?!

 

[Ricko1966]

I install the spreaders before unbolting, that way the holes don't change position from the manifold pulling them together. Makes it easier than installing the spreader after the fact, then finding the right spot for 4 bolts to get started and then spread the other side to install the other two bolts.

I've had friends that just cut and ground pieces of round stock to fit tight,then pried them out after install. Had a pair of customers that were best buddies that made a tool for spreading them,they'd spread them on a bench cause you couldn't use thier contraption on the car,then wedge in their long dowels they made. I only found out later after we all became friends. Because they borrowed my tool then told me how they used to do it with out the tool.

 

[tj43]

Okay, here is the direction I am leaning:

1) Buy a set of Hooker SBC manifolds (raw finish),
2) send the Hooker manifolds to Jet-Hot for a proper ceramic coating,
3) have my exhaust shop install them and fab a new Y pipe since the hooker manifolds use a two-bolt flange.

Part of me likes keeping the truck original. But, I already have a Dorman manifold on the passenger side, and my original manifold on the driver's side is nearly 40 years old and has an ugly plug on it where I deleted the AIR system. Plus, despite refinishing the manifolds during the engine swap, they are already starting to develop the "manifold crust." Additionally, the Y pipe is the weak link in my current exhaust setup.

Thoughts?

 

[DoubleDingo]

I've had friends that just cut and ground pieces of round stock to fit tight,then pried them out after install. Had a pair of customers that were best buddies that made a tool for spreading them,they'd spread them on a bench cause you couldn't use thier contraption on the car,then wedge in their long dowels they made. I only found out later after we all became friends. Because they borrowed my tool then told me how they used to do it with out the tool.

First time I was doing this type of work was when Pop was still wrenching and I was at the shop working on my deceased dad's 79 GMC. Up to that point I had only dealt with ramhorns and those are way easier. I was fighting getting the bolts started. Pop, in his nonchalant way walked up and saw that I was struggling, went over to his toolbox without saying anything, brought over this contraption, handed it to me and told to spread it apart in between the manifold bolt holes, but be careful not to overdo it or the manifold could and/or would crack because it's cast iron and cold. Once I got the 81 that was one of the first tools I bought because I hate fighting vehicles when wrenching.

 

[DoubleDingo]

Okay, here is the direction I am leaning:

1) Buy a set of Hooker SBC manifolds (raw finish),
2) send the Hooker manifolds to Jet-Hot for a proper ceramic coating,
3) have my exhaust shop install them and fab a new Y pipe since the hooker manifolds use a two-bolt flange.

Part of me likes keeping the truck original. But, I already have a Dorman manifold on the passenger side, and my original manifold on the driver's side is nearly 40 years old and has an ugly plug on it where I deleted the AIR system. Plus, despite refinishing the manifolds during the engine swap, they are already starting to develop the "manifold crust." Additionally, the Y pipe is the weak link in my current exhaust setup.

Thoughts?

If it's the subruban in your avatar "stock" has long left the train station, get new and be done with it.

 

[tj43]

If it's the subruban in your avatar "stock" has long left the train station, get new and be done with it.

It has a small lift, but is otherwise a very original truck. Build thread is here:

88 Suburban Build Thread

 

[DoubleDingo]

It has a small lift, but is otherwise a very original truck. Build thread is here:

88 Suburban Build Thread

Still not completely stock, that's all I was meaning. Good looking rig though. If you've removed emissions components, go with the new manifolds and exhaust and run with it.