TBI Headers?

[custodian]

I'm just about ready to drop the new 350 into my 85 C10. The 350 is a 75 model and the heads are the 87 up TBI 193 heads with the 1.94/1.50, 63.5cc heads.

I had an early set of stock cast iron manifolds, without the AIR holes, I intended to use. Went to bolt them up (mock up to make sure of fit) and found that the bolt holes don't line up.

I measured the bolt holes on the heads and the bolt holes on the manifolds and there was about an 1/8" difference. The manifolds were shorter.

Center to center on the mounting holes on the heads are 17 3/8". Center to center on the manifolds are 17 3/16".

UPDATE: The casting numbers on the exhaust manifolds are 30292 and 30092. They are GM. I don't think they are for the SBC.

UPDATE: I bolted up a set of Ram Horns to the heads.

I know the TBI heads have the extra hole, but did not bother with them.

Now my question: What headers will work on the TBI heads? Short heads that would bolt up to the exhaust pipes would be okay. I haven't searched anything yet.

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[bucket]

They are the same bolt pattern. The manifolds you have are problematic in that they heat warp badly. They actually sell "manifold spreader" tools so you can remove the manifolds without screwing up the threaded bolt holes and also so you can reinstall old used warped manifolds.

 

[bucket]

If you were to bake the manifolds in the oven, you would probably find that the bolt holes line up.

 

[Catbox]

I found these Pacesetter headers in the junkyard.
New they are $219 and I got them for $80 as they are specific to my 1995 Suburban.

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But, if you want inexpensive decently made headers.
The stainless steel headers from Ebay seem to work pretty well.
@Maxwellvis has a friend that has a set on his truck and they have nice thick flanges and decent enough welds on them.

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[custodian]

This is where I stand. If I put the bolts in at the back, the front two bolts will not line up. If I put them on the front, the back two bolts will not line up.

I'm thinking, either using bolts with no shoulders, studs, drilling all the holes out on the manifolds a bit bigger or do both.

I might even just buy the manifold spreaders, only about $12.

Like I said before, it's only about a 1/16" to 1/8" off.

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[skysurfer]

Your engine is just refusing to cooperate until you get rid of the crappy Fram oil filter.

 

[bucket]

This is where I stand. If I put the bolts in at the back, the front two bolts will not line up. If I put them on the front, the back two bolts will not line up.

I'm thinking, either using bolts with no shoulders, studs, drilling all the holes out on the manifolds a bit bigger or do both.

I might even just buy the manifold spreaders, only about $12.

Like I said before, it's only about a 1/16" to 1/8" off.

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Drilling out the holes may not be a bad idea if you are dead set on those manifolds. It will give a little more room for expansion and contraction and they may not be as likely to crack from the constant stress.

 

[custodian]

Drilling out the holes may not be a bad idea if you are dead set on those manifolds. It will give a little more room for expansion and contraction and they may not be as likely to crack from the constant stress.

I'd like to keep these manifolds, when I got them I bought the entire dual exhaust system. I just ordered the exhaust spreaders (2 of them). Still might drill the holes out.

 

[custodian]

UPDATE: I drilled the two center bolt holes the same size as the ends on the drivers side, the ends were 1/2" holes. Almost, but still not enough. I received my spreaders today, and in they go. I didn't drill the bolt holes out on the passenger side, just used the spreader.

I haven't put the gaskets on yet, just test fitting stuff before I install the motor.

Now, should I use a higher grade bolt?

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[MikeB]

Your engine is just refusing to cooperate until you get rid of the crappy Fram oil filter.

Yes, one of the worst you can buy. No comparison to Wix or Mobil 1.

 

[MikeB]

Now, should I use a higher grade bolt?

Not sure what the factory would have used. If what you have in the pictures are Grade 5, that's probably fine.

On another note, you may want to open up the exhaust outlets as much as you can. As I recall they are necked down to around 1-7/8" if that much. But externally, yours are nice -- no tapped EGR and AIR holes!

 

[custodian]

Not sure what the factory would have used. If what you have in the pictures are Grade 5, that's probably fine.

On another note, you may want to open up the exhaust outlets as much as you can. As I recall they are necked down to around 1-7/8" if that much. But externally, yours are nice -- no tapped EGR and AIR holes!

Those are standard 3/8" bolts. Might go to grade 5.

 

[bucket]

Iirc, factory bolts are grade 5. I'd use that or grade 8.

 

[rt66paul]

Use grade 8 or get a set from gm, grade 5 are too soft and the heat will almost weld them in. I would also use some kind og graphite grease coating, steam fitter's "Never Seize" or something similar. You can also put some on the gasket so it won't bake on. #0 years as a pipefitter/boilermaker taught me this.