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ZZ4 and Rams horns?

itsa64

Member
Joined
Apr 22, 2005
Messages
13
Location
Boston, MA
Corvette
1964 Riverside Red
I am in the planning stages for swapping in a zz4. Can I use my existing rams horn exhaust manifolds to my sidepipes? I may lose some HP correct?

Thanks
itsa64
 

Muttley

Active member
Joined
Mar 5, 2003
Messages
41
Location
St. Petersburg, FL
Corvette
1962 Silver/Red NOM 350
I considered a ZZ4 for a while, and asked around about this issue. The rams horn manifolds should bolt up just fine to the ZZ4 heads, but there are two issues to bear in mind:

One, I believe that the exhaust ports are slightly elevated on the ZZ4 heads (as compared to stock iron heads), but the difference is small and there is generally enough flexiblilty and "give" in the exhaust system that this isn't a problem. I have heard of interference between the manifold and the centerbolt-style valve cover, but that may be cured by one (or some combination) of: thicker gasket, different valve cover, or some external grinding on the manifold.

The other issue is that the ZZ4 heads have a slightly larger, D-shaped port opening, and that will create a mismatch with the stock iron manifolds. I have heard (again, second hand info), that there is enough "meat" on the manifolds that they can be opened up and matched to the port openings using a die grinder. (Note, this is apparently not true if using "fast burn" heads, which have even a larger port opening than the ZZ4 heads do--so bear that in mind if you consider upgrading to fast burns).

Perhaps someone who has done this swap can chime in and confirm, but this seems to be the "scoop".

On the HP issue--I'm reluctant to even touch that one. My own opinion is that a set of port matched rams horns ought to do about as well as a set of shorty headers. I have no data to back that up, though. Beyond that, you're into the standard header vs. manifold debate.
 

vettefinderjim

Well-known member
Joined
Apr 12, 2001
Messages
317
Location
Bandera, Texas
Corvette
orginal owner 77
ZZ4 was designed to be used in place of........

I know of at least five solid axel Corvettes and three mid year 63-67 cars that have bolted in this engine using all original exhaust with no problems. The ZZ3 heads were cast iron, so things matched up better, but the ZZ4 motor was designed to use in place of the old 283, 327, or 350 it may be replacing.

Just remember the flywheel is internal balance, and therefore the 'OLD ORIGINAL' flywheel must be the newer style for this new engine. Your Chevy parts guy can help.
 

Bwmurph

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Joined
Dec 24, 2003
Messages
388
Location
Conway, SC
Corvette
'59 Blk/Red, '12 Crystal Red GS
I've got an earlier crate motor in my '59 and I did have to do some grinding on the rams horns in the area where they come in contact with teh center bolt valve covers.

Other than that they're fine, but, again, it's an earlier carte motor, not a ZZ4

Bernie O.
 

Bill75

Well-known member
Joined
Jan 1, 2004
Messages
698
Location
Somers CT
Corvette
75 Coupe ZZ4, Brodix IK-180's, Headers,TK0-500
When I put my ZZ4 in last year I used the rams horns and std exhaust. Everything bolts up just fine and no leaks. I did not however look at the installation for performance issues so I didn't care about any slight mismatches that would cause restricted exhaust flow so I can't offer you any insight there. I installed them for the first startup of the motor and for the break in period because I didn't want to overheat my new headers reving the engine for 20 minutes breaking in the cam. Afterwards I found out I wasted my time and energy, the ZZ4 motor does not require the high rpm break in period.
 

itsa64

Member
Joined
Apr 22, 2005
Messages
13
Location
Boston, MA
Corvette
1964 Riverside Red
When I put my ZZ4 in last year I used the rams horns and std exhaust. Everything bolts up just fine and no leaks. I did not however look at the installation for performance issues so I didn't care about any slight mismatches that would cause restricted exhaust flow so I can't offer you any insight there. I installed them for the first startup of the motor and for the break in period because I didn't want to overheat my new headers reving the engine for 20 minutes breaking in the cam. Afterwards I found out I wasted my time and energy, the ZZ4 motor does not require the high rpm break in period.

Question 3: The ZZ4 has serpentine belt system, so if I do a swap do I need a whole new setup for my power steering pump?
 

KANE

Moderator
Joined
Mar 2, 2002
Messages
3,244
Location
KY
Corvette
Dark Blue 1982 Trans Am(s): Polo Green 1995 MN6
Question 3: The ZZ4 has serpentine belt system, so if I do a swap do I need a whole new setup for my power steering pump?

No- V belts are just fine. Just use the original running gear from your Vette. It should all bolt up without any issues.

If there problems with the accessories, evolution80 has a ZZ4 n his '80. He'd be able to tell you what he did to overcome them.
 

71zman

New member
Joined
Jun 12, 2005
Messages
2
Location
Palos Verdes, CA
Corvette
1960 Corvette White w/ red upholstery
I swapped the ZZ4 in my C1 and used Rams Horn Manifolds. The folks I bought the ZZ4 from gave me some interesting dyno information for exhaust manifolds. The bottom line is that you lose about 30 hp with the un-ported Rams Heads over a conventional 1 5/8" header set-up - all due to flow issues.

I wanted the Rams Horn manifolds to keep the origianl look so I made a pattern of the new ZZ4 D-port , transferred it to the manifold and opened the ports so they matched with my grinder. It was pretty painless to do and there was enough material on the manifolds so they fit the new heads.

Another method, although more expensive, is to buy the ported manifold form Brezezinski Racing http://www.castheads.com/ look under vette products.

Or, just use the heads as is and live with the power loss. There is no damage to the engine - in fact the GM manual that comes with the ZZ4 engine recommends the 2.5" Rams Horn manifolds if you do not have headers

Good Luck:beer
 

Evolution1980

Well-known member
Administrator
Joined
Feb 25, 2002
Messages
4,302
Location
Cleveland, Ohio
Corvette
ZZ4, 700R4, Steeroids rack & pinion, VB&P Brakes
Question 3: The ZZ4 has serpentine belt system, so if I do a swap do I need a whole new setup for my power steering pump?
The ZZ4 doesn't have any belt system in it's stock delivery from GM Performance. You can put a serpentine setup on it just as you could any engine that you wished to convert. But it ships from GM with no pulleys of any type. (For what it's worth, I'm running March Underdrive Pulleys on my car with no problems.)

You should have no problems using your existing pulley setup. The only thing you'll likely need to change is the water pump. When I bought my ZZ4 (5 years ago?) it shipped with a long neck pump. You need the short neck to keep the fan out of the radiator. So you can either reuse your existing water pump or go out an buy a new one. Most people I would think go out and buy a new hi-performance pump. Unless you just recently put a new one on your existing engine, for what a new one costs, it's a cheap piece of insurance to put a new one on the new engine.

I was also thinking about your exhaust question. I know that when I removed my Hooker Competition headers this past year, I noticed on the gaskets that I obviously was not mated up 100%. It seemed the ports on the heads were bigger than the primary tubes. I went to the Hooker Super Competition headers and they seemed to mate up better due to larger primary tubes....if I'm remembering this all correctly.
Now here is where I'm really going to go out on a limb. There's the slightest potential that because the ram horns won't give you full, unimpeded flow from the heads (going by what others' have said above), you could be potentially increasing your low end torque due to increased back pressure, but at the expense of upper RPM horsepower. Maybe???:confused ;shrug
 

itsa64

Member
Joined
Apr 22, 2005
Messages
13
Location
Boston, MA
Corvette
1964 Riverside Red
You guys are awesome! Thanks for the tips...

One more ???. Can I keep the original 4 speed manual for now or should I be lookin' at the new 5/6 speed tremec's???

I am on a budget..................... :confused
 

Evolution1980

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Administrator
Joined
Feb 25, 2002
Messages
4,302
Location
Cleveland, Ohio
Corvette
ZZ4, 700R4, Steeroids rack & pinion, VB&P Brakes
You guys are awesome! Thanks for the tips...

One more ???. Can I keep the original 4 speed manual for now or should I be lookin' at the new 5/6 speed tremec's???

I am on a budget..................... :confused
One thing at a time. Doing a trans-swap is not cheap from what I can recall. It's not a plug-n-play swap. Take you time and enjoy your car as you slowly build it up. I would say that most of our cars are an evolution (intentional reference) that takes place over time. With the engine out, it would be a fine time to replace the clutch pack, but other than that, I'd definitely hold off on a trans swap if you're trying to adhere to a budget.
And there's my 2¢ added to your budget. :D
 
Joined
Jan 1, 2002
Messages
7,246
Location
Washington, Michigan
Corvette
'67 Marina Blue Convertible
You guys are awesome! Thanks for the tips...

One more ???. Can I keep the original 4 speed manual for now or should I be lookin' at the new 5/6 speed tremec's???

I am on a budget..................... :confused

The Tremec 5-speeds (Keisler, etc.) are a great solution to the compromise between street performance and highway fuel economy, but will leave about a $3K hole in your budget. I wrote a step-by-step photo-illustrated article on a Keisler 5-speed install in a '65 in the April '07 issue of "Corvette Enthusiast" magazine. :)
 

itsa64

Member
Joined
Apr 22, 2005
Messages
13
Location
Boston, MA
Corvette
1964 Riverside Red
The Tremec 5-speeds (Keisler, etc.) are a great solution to the compromise between street performance and highway fuel economy, but will leave about a $3K hole in your budget. I wrote a step-by-step photo-illustrated article on a Keisler 5-speed install in a '65 in the April '07 issue of "Corvette Enthusiast" magazine. :)


:_rock Thanks John...I'll take a look!
 

BLACK MOON

Well-known member
Joined
Oct 21, 2003
Messages
654
Location
KNOXVILLE, TN
Corvette
15 Shark Grey 3LZ Z06
The Tremec 5-speeds (Keisler, etc.) are a great solution to the compromise between street performance and highway fuel economy, but will leave about a $3K hole in your budget. I wrote a step-by-step photo-illustrated article on a Keisler 5-speed install in a '65 in the April '07 issue of "Corvette Enthusiast" magazine. :)


I wish I had as much confidence in the Keisler set up as you John. My install was a problem and will be for anyone installing in a 63 without body cushions. The tunnel hit badly so I had to raise the body as well as cut out some places on my tunnel and re-glass. Then the driveshaft they sent was short so they had to make me a new one. This was all done while putting the body back on my frame. Well adding the cushions threw off all mydoor gaps (previously shimmed) so shimming wasn't enough and I had to cut and repaint my doors and jambs ( slight mis-match on the re-paint). Finally it all gets put together last summer and the transmission shifts like a 40's lumber truck. It's very, very, very tight. It also wants to jump out of gear and is almost impossible to downshift some days. Yes I did align the bellhousing. To top all of that off I had bought a Centerforce clutch setup ($375 +/-) right before I took the car apart (2003). Well a different spline disk is required and Centerforce wouldn't sell me one even though my PP and TO bearing only had 200 miles on it. Well I went with a Ram clutch package for $170. Well guess what the new throwout bearing squeals like crazy. So now the car is all shimmed and back together and I have a tight shifting transmission, a SQUEALING throw out bearing and door edges/ jambs that I can see a difference. Summary: Brand new! $3,000 trans. and $170 clutch, hundres of hours of work and several hundred in paint and none of it is the way it should be. Now it all has to come out because that transmission will not come out the bottom without cutting the transmission crossmember. The transmission has to be 'gone through', a new throw out bearing installed and the car repainted. Anyone want to buy a 63 that I have sweated over for 3 years? Sorry guys had to whine a little.
 

Evolution1980

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Administrator
Joined
Feb 25, 2002
Messages
4,302
Location
Cleveland, Ohio
Corvette
ZZ4, 700R4, Steeroids rack & pinion, VB&P Brakes
Aww, BLACK MOON, I hate to hear those kind of stories. I can somewhat feel your pain with the various issues I've had with my car over the years. Nothing as drastic as yours, but still enough to cause me a slight wince!
Ah well, we all keep moving along nonetheless! :beer
 

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