# Exhaust Dilema



## zzomby (Aug 23, 2009)

Hey guy's, thanks for the advice on my oiling problem. I have another puzzle to sort out. My car is a 65 GTO. The engine is a 65 389 Tri-Power with 7H1 heads, which I believe to be 73' 350. They have 4 bolt holes on each side for the exhaust manifolds to bolt to. I was going with the ram air 3 manifolds but they wont work according to Year One Catalog due to interference issues with the frame. Also the right side manifold has 5 bolt holes. Long story short> Does anyone know which manifolds I should run with? Or better yet will any headers bolt up and still fit my car? Thanks. :willy:


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## even steven (Feb 27, 2009)

ames performance sells doug headers for 64-67 gto's for 479.00 a pair


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## VettenGoat (Jun 19, 2007)

Odd that you have post 1967 heads on a 65 motor since the valve angle was different. Do you have pistons from a 400 in the 389? On the exhaust manifolds, you can run Ram Air manifolds, but you need to get the version that was offered in 1967. I was fortunate enough to find a pair of original 67 RA exhaust manifolds (part #9777646 drivers side). They fit a 65 fine and sound/perform every bit as good at the headers.

If you want a cheaper alternative while you look (or save up) for a set of 67 RA manifolds, I still have the headers I took off my 65 sitting out in the garage. If you're interested , send me a PM at [email protected]. They won't win a beauty contest, but they are solid and for a 65, and in my way.

Mike


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## geeteeohguy (Feb 2, 2008)

VettenGoat makes a good point with the pistons: 389 pistons have valve reliefs in a different location than 400 pistons. Common to see std. bore 400 pistons in a .060 overbored 389, though, and less expensive. On the manifolds: the repro high performance HO manifolds bolt right on to a '65 with no mods at all. BTDT.


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## zzomby (Aug 23, 2009)

Now you guys got me wondering what I have inside my motor. 7H1 heads 72' 350, behind the distributor 9778789, L44 date code.The block has 2 freeze plugs per side, characteristic with the pre 67' I believe. The thing throwing me off is the YG code on the front of the block. Can't find it. Thanks for the advice on the exhaust. The way I see it I can use 67' Ram Air manifolds and they wont interfere with my frame or anything. Only having 4 bolt holes makes it hard to bolt up headers.


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## zzomby (Aug 23, 2009)

Also it appears that I will have to drill another hole in the left hand side. driver side. right?


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## 68greengoat (Sep 15, 2005)

zzomby said:


> Now you guys got me wondering what I have inside my motor. 7H1 heads 72' 350, behind the distributor 9778789, L44 date code.The block has 2 freeze plugs per side, characteristic with the pre 67' I believe. The thing throwing me off is the YG code on the front of the block. Can't find it. Thanks for the advice on the exhaust. The way I see it I can use 67' Ram Air manifolds and they wont interfere with my frame or anything. Only having 4 bolt holes makes it hard to bolt up headers.


This YG code matches the 9778789.......

YG B-body 65 389 338 4-speed 3x2 9778789 4

Or do you mean, you can't find YG stamped on the block?


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## zzomby (Aug 23, 2009)

Thanks for all your comments. I am now headed the right direction until the next obstacle


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## zzomby (Aug 23, 2009)

I bought the Ram Air manifolds, but the problem is I can't bolt them up solid. As you can see from the pictures that I hope load up fine. These 73' heads have no bolt holes at the ends. All I can think of is getting rid of these heads.? They are sexy looking manifolds though. Can't throw them out.


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## zzomby (Aug 23, 2009)

*Pics*

Man sorry never tried this before.


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## Too Many Projects (Nov 15, 2008)

Is there enough material in the heads to drill and tap them for the bolts. Looks like it's all freshened. That would suck to have to tear it all apart and change heads.


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## zzomby (Aug 23, 2009)

No they were cast without bosses for the end bolts so there is nothing to drill. Which leads me to ask,(Due to my inexperience with heads ) I don't know what configuration to go with. Maybe some 65-67' heads? I don't know what other parts of the engine is effected by changing heads.


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## zzomby (Aug 23, 2009)

:confused

Maybe a spacer or adapter of some sort would work. If I change heads these are definitly for sale.


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## Rukee (Feb 8, 2007)

How about a set of headers for the `73 heads??


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## geeteeohguy (Feb 2, 2008)

Headers wont work with only one bolt on each outer port....they'll leak and warp. Those non-drilled heads can usually be drilled and used. It's weird that yours don't have any material to drill through. All the non-drilled ones I've seen looked just like the drilled ones, but were missing the hole.


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## zzomby (Aug 23, 2009)

Rukee said:


> How about a set of headers for the `73 heads??


Will they fit my 65' frame Ok?


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## geeteeohguy (Feb 2, 2008)

I looked at the photo again.......those manifolds can be used as is. The original manifolds bolted up exactly the same way, they just didn't flow as well. Shouldn't be a problem to just bolt them up and run them as planned. Also, you will need to change the routing of your positive batt cable to the starter. Refer to the 1967 GTO HO references out there....the cable runs from the front of the engine, thru a different guide tube, not thru the rear of the exhaust and tube, like a stock set-up would. The cast iron manifolds you now have should be rigid enough to seal with no end bolts and the stock steel gaskets.


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## zzomby (Aug 23, 2009)

geeteeohguy said:


> I looked at the photo again.......those manifolds can be used as is. The original manifolds bolted up exactly the same way, they just didn't flow as well. Shouldn't be a problem to just bolt them up and run them as planned. Also, you will need to change the routing of your positive batt cable to the starter. Refer to the 1967 GTO HO references out there....the cable runs from the front of the engine, thru a different guide tube, not thru the rear of the exhaust and tube, like a stock set-up would. The cast iron manifolds you now have should be rigid enough to seal with no end bolts and the stock steel gaskets.


My only concern is the passenger side with 2 bolts in it. It just looks like it will leak.


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## zzomby (Aug 23, 2009)

I read in the Ames Performance catalog the info about the 73' heads having no end bolt holes, also no bosses were cast to allow you to drill anything. Who thought of that one? 72' heads not 73'


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## geeteeohguy (Feb 2, 2008)

Yeah, you need at least 4 bolts. Two won't cut it. You need at least one on each end flange.


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## geeteeohguy (Feb 2, 2008)

You have two options: put the '65 exhaust manifolds back on, using 4 bolts, or to change out the heads. Sorry for the bad news. You MAY be able to put a stud in the front bolt hole of the rear port, and work a nut onto it....maybe.


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## Bobbyg (Jul 22, 2009)

Nothing to be sorry for. Those are good pics.

I understand that problem now.

Learn something new every day.


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## zzomby (Aug 23, 2009)

geeteeohguy said:


> You have two options: put the '65 exhaust manifolds back on, using 4 bolts, or to change out the heads. Sorry for the bad news. You MAY be able to put a stud in the front bolt hole of the rear port, and work a nut onto it....maybe.


Anyone have some stock manifolds they don't need? I have a sexy set of 67' Ram Airs to sell it looks like. I don't want the heads on there. Originally the guy I bought the motor from was putting it in a 68' Gto so that explains the 73' heads I guess. Will stock 65-67 heads work still with the 400 pistons that you guys think I have. Thanks geeteeohguy.:cheers


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## Too Many Projects (Nov 15, 2008)

If you're thinking of changing the heads, hang onto those RA manifolds. Most period correct heads will accept them. Hard to say what is in there for pistons till you get the heads off. If you stay with a similar size chamber (cc's) then you might not have to change the pistons too. This could turn into quite the snow ball..... I guess pulling the heads to see what you need is the first step. You could always put them back on if it gets to be too much hassle and go with stock manifolds.


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## Too Many Projects (Nov 15, 2008)

Here's a pic of a 6X head. Take the RA manifold off and look where the lower front and rear bolt holes are in the pic on your head. It seems strange that it wouldn't have material there to drill and tap in to. Also, the info I found on a 7H1 is a 72 350 with 1.96 intake and 1.66 exhaust with 80cc chamber. THAT is why he has those heads. That is a small chamber for a smog era head and the valve may be small enough to not interfere with the piston or cylinder wall. You could find several other heads in that size with more bolt holes that should be compatible with whatever pistons you now have. 
Post a pic of your head without the manifold....:willy:


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## geeteeohguy (Feb 2, 2008)

Okay, Zzombie.....it's time to step back for a minute and look at the whole picture. I think you're ok. You've got late heads on that engine, so any head from '67 up will work with your pistons. The 80cc heads now on it are ideal for about a 9.5 compression ratio. But, it'll be tough to hook up decent exhaust. As I said before, you MAY be able to but a stud in the pack bolt hole and use a nut. 3 fasteners per side will work: the manifolds are thick and solid and will seal. You have the engine out. Much easier to change heads or experiment with manifolds now, than later. If I were in your shoes, I'd try the stud and nut idea. It that didn't work, I'd hunt for some '70 455 heads (87cc chamber..hard to find) or some 90cc heads from a '72--'74. You'll need to go on the Wallace Racing website or others to find casting numbers. If you're rich, you could spring for some aluminum Edelbrocks and be done with it. You could also run stock, non-ho '65 up cast manifolds (they're out there) and be done with it. They're not THAT bad. (I'm running them on my '67). As Mitch said, hold onto the HO manifolds you have. You may need them later, they won't go bad, and they won't get any cheaper. Keep us posted. You'll get it figured out.


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## zzomby (Aug 23, 2009)

Here they are Mitch


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## Too Many Projects (Nov 15, 2008)

Wow, that is just bizarre that they would leave out that material. Looks like geeteeohguy is right. Change the danged heads or go with stock manifolds.
Here's a link to the site I imported the pic from. He has a good chart to compare heads.
Pontiac Cyl Head ID Information


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## zzomby (Aug 23, 2009)

Thanks to everyone who helped me on this subject, and help in advance to future subjects. I'm going to fire it up after work Monday. Too bad we all don't live in the same neighborhood. Lots of noise. My Pypes exhaust just came to my front door step. And my rusty old 65' headers bolted up to my motor so all is well, thanks again.


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## zzomby (Aug 23, 2009)

geeteeohguy said:


> Okay, Zzombie.....it's time to step back for a minute and look at the whole picture. I think you're ok. You've got late heads on that engine, so any head from '67 up will work with your pistons. The 80cc heads now on it are ideal for about a 9.5 compression ratio. But, it'll be tough to hook up decent exhaust. As I said before, you MAY be able to but a stud in the pack bolt hole and use a nut. 3 fasteners per side will work: the manifolds are thick and solid and will seal. You have the engine out. Much easier to change heads or experiment with manifolds now, than later. If I were in your shoes, I'd try the stud and nut idea. It that didn't work, I'd hunt for some '70 455 heads (87cc chamber..hard to find) or some 90cc heads from a '72--'74. You'll need to go on the Wallace Racing website or others to find casting numbers. If you're rich, you could spring for some aluminum Edelbrocks and be done with it. You could also run stock, non-ho '65 up cast manifolds (they're out there) and be done with it. They're not THAT bad. (I'm running them on my '67). As Mitch said, hold onto the HO manifolds you have. You may need them later, they won't go bad, and they won't get any cheaper. Keep us posted. You'll get it figured out.


Well, I connected the headers and dropped the motor in. I think I can use those headers for break-in just fine. So if I tap a hole in the Ram Air manifolds would it lessen the value for resale of the manifolds? Also how corny would it look with the nut showing? That is if I understand you right about the stud idea. The passenger side second hole from the rear is what I think you are talking about.


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## geeteeohguy (Feb 2, 2008)

Yeah, it would lessen the value. It just needs to be drilled, not tapped. The HEAD is tapped. But, looking at it, and looking at a friend's '67 yesterday with the same manifolds you have, I don't think there's enough room even for a thin nut to fit. It looks like the manifold is just too beefy. You may be able to modify the passenger side manifold just enough to clear a nut, though. BTW, my friend's '67 uses 3 bolts on the pass side and 4 on the drivers side. That's how they were designed, and they seal up just fine!


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## zzomby (Aug 23, 2009)

oh, I am thinking opposite of what you were trying to explain to me. I was going to drill the head and tap the exhaust manifold put a stud in the exhaust manifold and put a nut above the port in the head. After I run the engine and break it in I planned to install the ram air manifolds just for experimental reasons. And I am sure everyone who has read this post cant wait to find out the outcome. Me especially.


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## geeteeohguy (Feb 2, 2008)

No, you're turned around. The bolt hole you need to use is already there in the head. You just can't get a bolt into it due to the manifold shape. If you screw a stud into the head, you may be able to slip the manifold into place and put a nut on it. Then it will work. 3 fasteners on the pass side is stock, and ok!


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## zzomby (Aug 23, 2009)

You were right. They bolted up and they don't leak. yea haw. Thanks


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