Exhaust Manifold Interchange Question

FC Zach

Active member
I purchased an OEM 7 hole flange manifold from a member to eventually use on my engine since I prefer it over my tubular manifold but the other day I noticed a difference between the two and counted the exhaust manifold studs on my head. I counted 9 studs. . All 7 holes on the OEM manifold seem to align up with 7 of the 9 holes on the tubular manifold, will it fit or is spacing between studs completely different?

What exactly do I have (what did I buy), is it a gen1 3S-GTE?
 

quieter

Member
its going to fit but you might need to cut a bit the hole for the stud halfway in the top right when looking at the engine because it might not clear. otherwise, its bolt on
 

mx6er2587

New member
My head is set up for a 9 hole. I currently run a 7 hole and have even had 1st gen (st165) manifolds bolted up to it. You should be fine.
 
I think the JDM heads have 9 studs and USDM ones have 7 and both came with 7 hole manifolds. I put a 9 bolt manifold on like yours I just had to cut/grind some of the alternator bracket. Also one of the studs must be shortened on the top, and you will need to cut off one of the little protrusions on the front of the head from my experience.
 

mx6er2587

New member
it should be a year difference not a usdm/jdm difference. 90-91 are 7 stud and 92-93 are 9 stud.

You should not have to do any modifications to bolt a 7 stud manifold to a 9 stud head.

You may have to do some modification to bolt a 9 stud manifold to a 7 stud head. (besides the obvious of only using 7 studs)
 

yyonline

Member
If it helps any, the previous owner of my car converted from a 7-stud to 9-stud manifold.

According to him, the early 92 block was tapped for 9 studs, but only had 7 studs installed, and two empty holes. So he bought studs to put in the 2 empty holes and the 9 stud manifold bolted right up.

I assume you can do the reverse of what he did - remove 2 studs from the head and bolt the 7 stud manifold to the head. That will leave 2 empty holes in the block, but my understanding is that's how my car came from the factory.
 

alltracman78

Active member
You mean the head? The manifold doesn't bolt to the block. :)

90-91 are all 7 bolt.
Most 92 [all?] are 7 bolt [later ones might be 9 bolt; I've never seen a 92 with a 9 bolt manifold (I've owned 2, had 3 RC engines and seen several other 92s) but that doesn't mean none of them have it].
93s I would assume are all 9 bolt [I've had 2].

Keep in mind the alternator bracket is matched to the manifold.
A bracket for a 7 bolt manifold won't work with a 9 bolt manifold. But you can use a 7 bolt manifold with a bracket for a 9 bolt. I hope that makes sense. :)
 

FC Zach

Active member
My '92 is special, it has a 9 bolt manifold :) but really not sure what it was originally (previous owner swapped engine).

Thanks for all the info guys, I guess I'll be keeping my manifold now for future use.
 

yyonline

Member
alltracman78":20ymee1a said:
You mean the head? The manifold doesn't bolt to the block. :)

This is why I shouldn't post at 4am. :roll: I did say head elsewhere in the post though.

FC Zach":20ymee1a said:
My '92 is special, it has a 9 bolt manifold :) but really not sure what it was originally (previous owner swapped engine).

Toyota switched to the 9-boly head in August 1991 and the 9-bolt manifold in October of 1991. So depending on when your 92 was produced, it may have had the 9-bolt manifold from the factory.

alltracman78":20ymee1a said:
Keep in mind the alternator bracket is matched to the manifold.
A bracket for a 7 bolt manifold won't work with a 9 bolt manifold. But you can use a 7 bolt manifold with a bracket for a 9 bolt. I hope that makes sense. :)

I'm not aware of having to make any modifications to the bracket on my car. I'll have to check this out more closely once it stops snowing. Heck, I'm not sure I'll be able to see it anyway with everything Toyota crammed under the hood.
 
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