Author Topic: Exhaust Advice Needed  (Read 15936 times)

BULLITT65

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Re: Exhaust Advice Needed
« Reply #15 on: March 20, 2018, 03:33:27 PM »
Well the original air cleaner isn't super expensive. He could purchase one for shows and then swap then in out as he pleases.

If it were me, I would swap the valve covers, and locate the coil over to the drivers side of the intake, and then just keep my eye out for an air cleaner.  :)
1969 garnet red Z/28 46k mile unrestored X77
-Looking for 3192477 (front) spiral shocks 3192851 (rear)
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bcmiller

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Re: Exhaust Advice Needed
« Reply #16 on: March 20, 2018, 03:47:16 PM »
Valve covers need to be swapped. No argument there. 

Bryon / 1968 Camaro SS 396 coupe - now old school 468 big block
1967 Camaro RS/SS 396 coupe L35/M40 - 4 generation family project
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X33RS

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Re: Exhaust Advice Needed
« Reply #17 on: March 20, 2018, 03:59:30 PM »
I used to see owners swap valve covers all the time on power brake cars back in the day.  Makes it much easier to get oil in the engine.  Some people still have that thought process it seems.


If that chamber exhaust isn't aggressive sounding, I'd guess the engine has no compression and/or camshaft in it.   Typically a small block with some compression and camshaft will make that exhaust system pop and cackle pretty good to the point of obnoxious.    Which is why many were recalled and eventually removed from the option sheet all together.

Our Z was built after chamber became non-standard, so it is equipped with the deep tone muffler setup.  Up until last year it still actually had it's born with exhaust system still intact on the car (now pulled and stashed away)

Here's a sound clip with it's 49 year old exhaust system.  Even this system is a little loud a cackly.  11:1 compression 302.

https://youtu.be/SDMeBoQpf58

Here is the Pypes transverse 2 1/2" system with "X" and tailpipes turned down behind the quarters 67-68 style.  Deeper tone, not cackly anymore, but was a bit too loud for my wife.

https://youtu.be/5dTNw93VPEQ

So I adapted factory reproduction 69 2" tail pipes to the system to help tone it down a bit.  It's now very quiet inside the car and comfortable to carry on a conversation.

https://youtu.be/IZ0HlEY7b74     

Here's a ride along inside the car.  Just the first minute and a half is all that's needed to get an idea of the noise level inside.

https://youtu.be/5vX6hVQ_cKw   


70z28lt1

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Re: Exhaust Advice Needed
« Reply #18 on: March 20, 2018, 05:14:28 PM »
"Coffin" or "clamshell" or "flanged" whatever you want to call it power steering pump.  Those weren't on cars until 71.

z28z11

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Re: Exhaust Advice Needed
« Reply #19 on: March 21, 2018, 01:59:17 AM »
Change the ground cable to black.

Exhaust manifolds are wrong - those manifolds are for an automatic with Therm AC heat stove. You'll need to add a smog system to be totally correct.

Add spark plug shields -

Still, a good looking engine bay and car. I like it -

Regards,
Steve
1968 Z28 M21/U17 BRG/W 1967 Chevy ll Nova SS 
1969 Z28 X77/M20/VE3 LeMans/W
1969 L78 X66/N66 Cortez/BVT
1969 Z11 L48/M35/C60/C06  1949 3100 5wd 235/6

HawkX66

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Re: Exhaust Advice Needed
« Reply #20 on: March 21, 2018, 12:20:27 PM »
Here's a video of my 69 with an extremely mild 408ci. 402ci bored .030" over. It has 2" Doug's Headers (which were a little too big for that motor) and the Flowmaster American Thunder system on it. I've always been real happy with the sound. It's a nice happy medium.




The sound quality on this one isn't quite as good.




And last, but not least.



Dave
69 SS396 X66 L34 M21 BS
Z23 711 U17 Hugger Orange
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X33RS

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Re: Exhaust Advice Needed
« Reply #21 on: March 21, 2018, 03:27:45 PM »
Video clips aren't working for me for some reason.

I ran both the American Thunder and the Force II FLowmaster transverse systems.   The American Thunder was hella loud with a ton of interior drone, after 6 months of daily driving I removed it. Switched to the Force II.   The Force II was more mellow, but oddly enough Flowmaster discontinued that system a few years back.

I ran both on my Formula, still have the systems stashed away.  I eventually switched my Formula to the same system I have on the Z I posted above.  I wanted the "X" cross over instead of the "H" was one reason for the change, and I wanted a stainless system was the other reason.  Plus the Pypes transverse muffler is touted as a straight through design and worth a little HP over the baffle/deflector style.  I was looking for a little edge in the Pure Stock racing category.

  Here is my Formula, setup to run Pure Stock with it's original 400 RAIII, running stock RA manifolds and the same Pypes 2 1/2" system.

https://youtu.be/er1z7PpqsnY     

Not only did the car pick up about 2 tenths with this system over the others, but it's also a very mellow sound, no drone in the car, very quiet to cruise down the road in.

Here's a ride along to get an idea how quiet it is inside the car.  Matter of fact, it's so quiet inside, I could hardly hear my car at all with the "open header" car next to me.  So much so that I quit looking at the tach for a few seconds and didn't even realize I had run 2nd gear out to 5700....Oooops.  It runs best shifting around 5200.

https://youtu.be/bpFwscg7uoY   

bheston

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Re: Exhaust Advice Needed
« Reply #22 on: March 21, 2018, 10:07:06 PM »
Change the ground cable to black.

Exhaust manifolds are wrong - those manifolds are for an automatic with Therm AC heat stove. You'll need to add a smog system to be totally correct.

Add spark plug shields -

Still, a good looking engine bay and car. I like it -

Regards,
Steve

Rookie question: What are the differences between automatic exhaust manifolds and manual exhaust manifolds?

69Z28-RS

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Re: Exhaust Advice Needed
« Reply #23 on: March 21, 2018, 10:09:30 PM »
Manual transmission cars included the A.I.R. system... so the manifolds are drilled for the AIR tube connections.   For automatic transmission cars, the air cleaner is different..   and I've got to go (wife is calling me) so someone else can fill in the rest.. :)
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bheston

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Re: Exhaust Advice Needed
« Reply #24 on: March 21, 2018, 10:59:12 PM »
Ah, thanks. I found some pics on-line. So ALL 1969 V8 manual shift had the AIR system from the factory?

z28z11

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Re: Exhaust Advice Needed
« Reply #25 on: March 22, 2018, 03:20:45 AM »
Yep. My L48 Pace Car is an auto, no A.I.R. All three of my manuals (68 Z, 69 X77, 69 L78) have them. Also, one of the first parts to be taken off the car when new, for a lot of owners.

You can buy reproductions, they're fairly close, OE's will cost you some bucks. Here again, depends on what you want to do to the car - restore, or mild modify. Headers will wake up the performance of the small block, and your neighbors will love the improvement to your exhaust note.

Regards,
Steve
1968 Z28 M21/U17 BRG/W 1967 Chevy ll Nova SS 
1969 Z28 X77/M20/VE3 LeMans/W
1969 L78 X66/N66 Cortez/BVT
1969 Z11 L48/M35/C60/C06  1949 3100 5wd 235/6

KurtS

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Re: Exhaust Advice Needed
« Reply #26 on: March 22, 2018, 05:10:20 AM »
Kurt S
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bheston

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Re: Exhaust Advice Needed
« Reply #27 on: March 22, 2018, 09:58:14 AM »
Thanks for the info! I bought a set of correct cast number manual manifolds and feel compelled to pull and replace the auto manifolds this spring.  My plan would be to plug the AIR ports and not attempt to restore the emissions.  Iím not trying to make this 100% original, but I appreciate and prefer the look of how The General intended.  There will always be a few things that I canít change or prefer not to change. Itís unclear to me if the true subject matter experts will see this as wearing a non-earned war metal or if folks appreciate the intent.  I suppose there will always be both opinions.

z28z11

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Re: Exhaust Advice Needed
« Reply #28 on: March 22, 2018, 02:01:18 PM »
Not a bad idea. A lot of people that re-install the smog systems will make them non-operational by plugging the manifold tubes, and gutting the pump (removing the vanes). Creepy things caused problems for a lot of owners (and restorers); hurt performance, but the visual requirement for correctness is there when doing a detailed restoration. Dated parts with part numbers, too, for all of us number fanatics.

Regards,
Steve
1968 Z28 M21/U17 BRG/W 1967 Chevy ll Nova SS 
1969 Z28 X77/M20/VE3 LeMans/W
1969 L78 X66/N66 Cortez/BVT
1969 Z11 L48/M35/C60/C06  1949 3100 5wd 235/6

BULLITT65

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Re: Exhaust Advice Needed
« Reply #29 on: March 22, 2018, 02:05:23 PM »
The things we are pointing out, most observers at a car show will not notice. Most will appreciate that it looks stock.

Likely only a CRG guy would be able to point out, what is incorrect. In the end you are the only one that has to be happy with the end product. :)
1969 garnet red Z/28 46k mile unrestored X77
-Looking for 3192477 (front) spiral shocks 3192851 (rear)
-Looking for an original LOF soft ray windshield
-Looking for original Delco side post negative battery cable part # 6297651AV