GM H-Body V8 Exhaust FAQ
(frequently asked questions)
By Bob Gumm
(Please be patient, this page has lots of information!)

* Some pages require Microsoft Word and Excel v7 for Windows95 .

Exhaust System

   Factory Manifolds
75 Monza/Nova Exhaust Manifolds
	RH part no.: 354432 (Log Type Design / Passenger's side)
	LH part no.: 354433 (Ram's Horn Type Design / Driver's side)

   I have used two different makes of headers and the factory manifolds.   The factory manifolds don't make as much power, but they are very reliable and trouble free.   The pictures show what the right (passenger's side) manifold (GM part no.: 354432) looks like, it fits A, B, and X bodies as well.   It is recessed slightly between the #6 and #8 exhaust ports to clear the upper control-arm tower in the engine compartment.   This recess is slightly noticeable in the lower right photo, just to the left of the "Factory RH Ehaust Manifold" label and is where the part number is found.   The left (driver's side) manifold (GM part no.: 354433) (next picture) is routed above the exhaust outlets (similar to some F-bodys and Monte Carlos) then drops down to the collector between the #5&7 outlets.   Contrary to popular belief, these manifolds are not limited to the V8 Monza only, they can also be found on 262 c.i. equipped '75 Novas as well. Don't get ripped off buying manifolds made for another vehicle because chances are they won't work.   I still have mine in case I get tired of the headers.

Factory V8 Monza RH & LH Exhaust Manifolds
Factory V8 Monza Oilpan and RH Exhaust Manifold
Factory V8 Monza LH Exhaust Manifold, factory V8 oil pan in background.


  
Aftermarket Exhaust Systems and Headers (
e-mail me if you use these kits)
   Most V8 H-body headers you will find are advertised to fit the Vega or Monza, but they will fit all H-bodies.   However, some headers "REQUIRE" a V8 mount kit because the header tubes run in the areas where the Monza factory V8 mounts are located.   This does not mean that you can't use Monza motor mounts, It just means that you may have difficulty using them and should use their kit.   Of course headers are like all other aftermarket equipment, they usually have to be dented here or there to fit just right.   The headers do make a lot more power, but they can rub the steering column and other things and may leak so badly that they burn plug wires, gaskets, etc..   Most of my header problems stem from the fact that I have oversized exhaust ports and I'm too miserly to pop for the $799 racing headers and instead use the street versions.


Don Hardy V8 Vega Headers
We now offer the Don Hardy V8 Vega headers, V8 installation kits, and other performance products.   See our catalog for more information.
V8MONZA.COM Catalog Page 1

   I used these once before with the factory V8 mounts, so I know they'll fit with factory mounts.   They actually cleared the factory V8 mounts and steering column better than the Hedman P/N 68340 or Hooker P/N 2129 do (neither are designed for factory mounts).   However, to be fair Hooker P/N 2135 headers are designed for and clear the factory V8 mounts very well (see Hooker Headers below).   I only got rid of the Don Hardy headers because I ported the exhaust ports on my heads so big that they leaked past the sealing bead on the headers.   Note that the collectors are aimed outward on both sides so that the exhaust tubes that connect to the collector flanges have to be bent in a slight S-shape to neatly tuck the exhaust under the car.   They're great for racing, don't require cutting holes in the inner fender wells as no tubes pass through the fenders, and they're easier on the wallet than any other full length header. The Don Hardy headers have 1-5/8" primaries.

Don Hardy V8 Vega Headers
Don Hardy V8 Vega Headers from below (photo by 75Monzta)


       Hooker Headers V8 Vega Kit.
Small-Block Chevy (262 - 400)

   The Hooker Chevy small-block headers were available as P/N (part number) 2129 and P/N 2135 (for use with factory motor mounts) for small-block Chevy engines.   Hooker's small-block V8 Vega headers are very similar to the Hedman Vega headers and as such probably won't work with A/C or power steering and won't fit factory installed V8 cars.   That is, the factory V8 engine mounts will interfer with the headers fit.   One tube on each side requires a hole cut into the fenderwell just above the brake-line so the tube can exit the engine compartment, turn down following the back of the fenderwell, turn back under and join the rest of the tubes at the collectors under the car.
   Hooker has two different small-block header kits, one fits the factory V8 Monza and clears the engine mounts.   The other set (V8 Vega) doesn't work with the factory engine mounts and should only be used with the Hooker small-block engine mount kit P/N 12601 ('71-'74 cars) or P/N 12608 ('75-'80 cars).   By the way, the Hooker mount kit looks exactly like the Hedman, Motion Performance and Trans-Dapt kits.   So if you can't find the kit through one try the others.

P/N 2129 - NOTES:

  1. 1-3/4" tubes, 31" long.
  2. One tube each side over frame.
  3. This header cannot be installed by using the stock location side motor mounts. This header requires:
    • 1971-74 installation kit #12601 which consists of front and rear motor mounts.
    • 1975-80 front motor mounts #12608.
    • 1975 rear mount #12632 for Turbo 400 installation.
    • 1975 rear mount #12633 for Turbo 350, 4-speed or aluminum powerglide installation.
    • 1976-80 rear mount #12635 for Turbo 350, 4-speed or aluminum powerglide installation.
    • All require any 1967-77 Camaro rubber transmission mount which fits your particular transmission.
  4. Installation with manual transmission requires the fabrication of a clutch cable bracket.
  5. Will fit with angle plug heads.
  6. Will not fit cast iron powerglide.

P/N 2135 - NOTES:
  1. 1-1/2" tubes, 31" long.
  2. Available with fittings to accommodate air injection manifold. Add a 0 in front of the part number when ordering.
  3. Will fit with angle plug heads.

Hooker V8 Vega Conversion Kit

Big-Block Chevy (396 - 454)
V8 Vega Kit by Hooker.

Hooker V8 Vega Big-Block Chevy headers    The Hooker Chevy big-block headers were available as P/N 2240.   Hooker's big-block V8 Vega headers are very hard to find today.   They won't work with A/C, power brakes, or power steering and require a remote oil filter conversion.   You will also have to modify the steering column by cutting it in a couple places and installing unversal joints (swivel links) so that the steering column may be rerouted around the left header. For those who don't like the idea of cutting their steering column, you may opt to install a Mustang II type rack-and-pinion steering gear box.

I have a set of these and a Motion installation kit, but have not installed them yet. A big-Block installation is not for someone who wants a drop in and go installation. This kit will require some skills and patience. Once installed there is no denying the shear power to weight ratio and the instant 10 second times that you should be capable of at the track. However, a Big-Block in a daily driver will quickly cause the car's front suspension to sag beyond adjustment. If you really must install a Big-Block in an H-Body, go the extra mile and install a complete frame and rollcage too.

   Hooker also has a big-block installation kit P/N 12603.  

P/N 2240 - NOTES:

  1. 2-1/8" tubes, 33" long.
  2. Two tubes over frame right side.
  3. This header cannot be installed by using the stock location side motor mounts. This header requires:
    • 1971-78 front mount #12603.
    • 1975 rear mount #12632 for Turbo 400 installation.
    • 1975 rear mount #12633 for Turbo 350, 4-speed or aluminum powerglide installation.
    • 1976-80 rear mount #12635 for turbo 350, 4-speed or aluminum powerglide installation.
  4. All require any 1967-77 Camaro rubber transmission mount which fits your particular transmission.


       Hedman Hedders (that's how they spell it)
   The Hedmans were available in two part numbers, 68330 and 68340.   I don't have any information about P/N 68330 at this time.   However, according to Hedman, P/N 68340 won't work with A/C or power steering and won't fit factory V8 cars.   Hedman says you need swap kit #20140.   One tube on each side requires a hole cut into the fenderwell just above the brake-line so the tube can exit the engine compartment, turn down following the back of the fenderwell, turn back under and join the rest of the tubes at the collectors under the car.

   I've used P/N 68340 with the Monza factory engine mounts and believe me, the headers really have to be bent a lot to clear the RH motor mount.   If you plan on using a mechanical fuel pump the headers will require even more denting as they become sandwiched between the RH motor mount and the fuel pump.   This really chokes the flow of the #2 tube.   These headers are so much like the Hooker V8 Vega headers that they are really hard to tell apart.

Hedman's Small Block V8 Vega Headers


       Stahl Headers
   As you can see by the photos, these headers are going to be difficult to install.   Also, it looks to me as though sparkplug changes on specific cylinders would be very difficult.   I've heard they are still available but it takes several weeks to get them as they are made only when they're ordered and are VERY expensive.
(Send me your pictures and comments on these headers.)

Stahl's #123 Small Block V8 Vega Racing Headers
Stahl's #123 Small Block V8 Vega Racing Headers
Stahl's #124 Small Block V8 Vega Street Headers
Stahl's #124 Small Block V8 Vega Street Headers

       Sanderson Shorty Headers ( 5 Stars)
   To the right is a picture of the "REAL" Sanderson V8 H-Body shorty headers, part number CC13.   They have 1 1/2" tubes and 2 1/2" collectors.

   To the lower-right is a picture from an ad Sanderson placed in the June 1999 issue of SUPER CHEVY magazine. As I stated from the start, I didn't see how the headers in the ad could ever fit V8 H-Bodies. The headers in the ad were incorrectly described as being for a V8 Vega or Monza and even a Nova. As it turns out, they only fit the Nova.   Below, Jeff and Aaron describe the correct Sanderson header that I believe may be just what many people want in a shorty header.   So, Sanderson makes an excellent shorty header for the V8 H-Body, they just don't have a good advertising department.   Read on for the whole story.

Jeff & Aaron sent me this e-mail:
   Sanderson headers are a shorty type header with 1.5" tubes, these are not equal length but they do fit into the engine compartment rather well.   I only had to ding one tube for spark plug clearance (the third back from the front on the drivers side) but if you are using angle plug heads even this is not necessary.   The steering column has to be removed to install the driver side header but the engine can be bolted in.   They are a barely proposition to get in on the drivers side but once in everything lines up it all fits with clearance (better than any header V/8 or otherwise that I have ever installed) to spare around the column.   The passenger side header almost drops right into place and fits without rubbing or interfering with anything.   On the steering column, if your car has power steering and /or a tilt column the shaft is a two piece affair that can be removed and reassembled rather easily but if you have a non power non tilt column it is a one piece arrangement that requires the complete removal of the column.   Getting the one piece column back in requires disassembling the joint at the end to allow it to pass through the header.   An easier solution is to procure a two piece column or use this as a good excuse to install a tilt column (we did).   Also remember when you take a steering column lower joint apart to mark what way it was assembled or you will have your steering wheel 1/2 turn out of whack and your turn signals won't cancel properly (voice of experience talking there).   We have installed three sets of these headers.   One set in a car where the engine was already a running unit with the aforementioned one piece column and the job was completed in a friend's driveway in one evening without any specialized tools.   Exhaust was done at a local exhaust shop for about $130 but we had bought the mufflers elsewhere as the shop did not carry the ones that we wanted.

   These headers dump in approximately the same places as stock monza V/8 manifolds but I doubt they would mate up to the factory Y pipe without considerable modification.   These headers are not for the really serious racer but are ideal for the fast street driver who does not want to drag off the bottom side of his expensive exhaust system.   Those Hooker headers that go under the car require lots of extra ground clearance and in Colorado you have to have 4" ground clearance to be legal.   On a Vega or Monza this requires jacking the suspension nearly to the top.   With our interest in road racing this is not feasible but we are not legal anyway as we have been running closer to 3".   Thankfully the CHP does not seem to care as long as it is within reason.

   Hopefully this has enlightened everyone and not confused anyone.
The phone number at Sanderson is 1-800-669-2430

We now offer the Sanderson CC13 headers.
See our catalog for more information.
V8MONZA.COM Catalog Page 1

Sanderson's Small Block V8 Vega Shorty Headers - P/N CC13
   These shorty headers, P/N (part number) CC13, are for V8 H-Bodies (Monza, Vega, and Clones) and they fit straight or angle plug heads.   Based on this photo and compared to my own factory manifolds and the space available in the engine compartment, they are sure to be easier than any other header to install as they look bolt-in.   However, as Jeff and Aaron state they require removal of the steering column and may need the #3 tube slightly dented to clear the #3 sparkplug, but they are as close to bolt-in as you can get.   Also, they will not bolt up to the factory cross-over pipe.
CAUTION: Steering shaft runs between the header and engine block. If motor mount(s) break or engine position shifts, the steering could lock up. Sanderson strongly recommends using rigid engine plates instead of conventional motor mounts.

Sanderson's Small Block V8 Nova Shorty Headers - as advertised in SUPER CHEVY magazine (June 1999)    These headers were incorrectly advertised to fit the small-block Chevy V8 equipped H-Body.   These headers do not fit the H-Body, they are for the Chevy Nova.   Sanderson's ad in Super Chevy magazine (June 1999), stated that P/N (part number) CC14, are for V8 Monzas and Vegas and they fit straight or angle plug heads.   Based on the photo Sanderson has supplied and compared to my own factory manifolds and the space available in the engine compartment, they are sure to be a disappointment as they look anything but bolt-in.   See Sanderson headers P/N CC13 (shown above this picture) for the correct headers.

   Below are some pictures of the Sanderson headers (P/N CC13) installed.   According to Jeff and Aaron, these headers dump in exactly the same location as the factory V8 manifolds.   Anyone that uses these, please give me the scoop on sparkplug changes, it looks like it would be a real pain.   More information is available at http://www.centuryperformance.com/sanderson20.htm#CC13, look for P/N CC13.
(Photos by SSEAN72)
Sanderson's SBC V8 Vega Headers (Driver's Side)    In this picture, you can clearly see that the steering column goes through the headers. This is why the column must be removed first before the driver's side header can be installed. Also notice that they don't leave much room to maneuver around during sparkplug changes.
Sanderson's SBC V8 Vega Headers (Passenger's Side)    Here you can see that the passenger's side header drops right in with little problem.   Why the owner of the vehicle dented the #6 tube is a mystery to me, maybe he will write and tell us.
Passenger's Side Header Collector    Here you can plainly see the passenger's side header collector in the factory location.   I think these headers look like they would make the average street enthusiast very happy with their ease of installation and obvious ground clearance advantage over other headers.

Back to Building the V8 H-Body
http://www.v8monza.com