MELVIN

Cost, $400, the coated version. Comes with all bolts, gaskets, reducer, flange, nuts/bolts
The set I ordered, as stated in the catalog, states " BB vettes. 396-502", w/4 speed. Keep in mind I have a 502, and ran into some probs, but the exterior dimensions of a 502 are the same for 396, 427, 454. I dont have AC, PB, or PS

Removing old:
1. They new ones look great. Very light compared to my stock 68 exh manifolds
2. Disconnect battery at both positive and negative sides, remove altenator. Remove all exh manifold bolts, all the old AIR stuff, all spark plugs.
3. Raise front of car at least 32-36" off the ground (if you use typical jackstand, that would be using the first hole).
4. Remove engine mount bolts, exh flange bolts. Remove first portion of exh pipe(from the engine side). If you have a one peice welded exh system, remove all clamps/hangers, and remove, or just slide back the exh system about 2 feet. Remove clutch pivot arm. Remove oil filter
5. Raise motor as far as you can with a hyd jack. I used one, with a pieice of wood under the oil pan. Raise it slowly until you start to feel resistance. The passenger side exg manifold will come out from the top or bottom easily, the drivers side needs to come out from above

Installation:
1. Install both from the bottom. Use light gloves, to keep grease, etc, off the headers. Use care, as you will scrape the headers against stuff as it goes up and in, especially the drivers side
2. Put in first and last header bolts in just a tad. Install gaskets, install rest of bolts, snug down, but dont tourque down yet. HERE IS WHERE MY 502 SPECIFIC probs came in: The lower head bolts on the 502 aluminum heads have a very tall head on them, enough that it would not allow the headers to fit down low enough on the exh ports to fit. The bolt heads would touch the bottom of the headers flat flange. I removed one of these bolts, and compared it to a 396 to 454 lower head bolt, and sho/ 'nuff, the 502 bolt heads were taller. So I replaced those on mine, with the 396-454 type.
The headers fit fine then.
3. Tighten down all header bolts. Install spark plugs, NOTE: The stock style plugs would not fit. You can install them by hand, but NO WAY are you going to tighten down #3/5. I got a set of autolites, with 5/8 head, and shorter ceramic towers. They fit, but number 3 is very tight. I had to take a spark plug socket, grind it down, so it would fit. Im sure Accel might make a shorty header plug, but couldnt find one in thier catalog with the long shank, as my 502 requires. The spark plug issue may be 502 head specific
4. Now you have to attach your exh to the new manifolds. So how do you get it to a muffler shop? I got 2, $6 a piece, ready bend, 18" long pipes at autozone. They fit perfect, and I clamped them down in place. I got lucky, as my first 18" inches of exh pipe had a clamp where it connected to the rest of the exh system (chambered exh)
5. Install spark plug wires. All fit fine, but #2, and #3 are close. #3 is the biggest prob. It touches, no doubt. I placed a layer of starter insulation around the plug wire boot until I get a thermal insulation boot
6. Replace all the acces's./install oil filter
7. Before Cranking: Remove all grease off the headers. I used simple green. Dont use anything caustic. I then used windex. Reconnect battery
ENSURE ALL WIRES(BATTERY WIRES, ETC) ARE OFF THE HEADERS.
Headers will smoke a little, as per instructions, for a little while after first start up. Check for exh leaks. Go for a drive. Retighten header bolts, reinspect spark plug wires, and any wires that come close to the headers.

Sounds great. As a matter of fact, the sound thru my chambered is more mellow in tone, and the really annoying resonanace I got with my stock exh manifolds on has really been reduced. I hadnt expected that. I thought it would be worse. .

The coating is supposed to reduce under hood temps, that Im not sure

Oh yeah: there is more umph noticable when hitting the gas.

An H Pipe comes next

norvalwilhelm

I have problems with number 1 and 3 plugs. In the other cylinders I use Accel # 276 but in these cylinders I use #276S "S" is for short. They are about 3/8ths shorter ceramic then normal plugs but the same heat range. I also use Jacob ceramic plug wires and boots on these cylinders. The ceramic spark plug boot will not burn or short.

73-454

I do not like headers, A few suggestions, make sure you protect any wiring and hoses with-in 5 inches of the new headers. Better get the starter insulated, If you have A/C make sure you wrap the headers close to your heater/ cooling box or it will melt the fiberglass. I think the way to go is stick with stock headers I do not believe there is any advantage to the after market crap in the performance of your engine

MELVIN

Everyone is entitled to thier own opinion, so Ill share mine back: The key to performance is more air in, and more out= more efficiency which equals more performance". Sorry, but I have run my BB exh manifolds a long time, and I can assure you, there is a performance gain by replacing the stock BB exh manifolds.

Also, take a look at how close your stock manifolds are to your starter right now. The headers I have now are definitley farther away from the starter now.

At lunch, I got out of the car, and checked the oil. As far as the coated headers go, there is definitley less radiated heat under the hood. Cast iron is like charcoal. It will hold and continue to radiate heat for a long time, and dissapates heat very poorly

Ill say though, the spark plug issue is a pain. Shorty plugs are the key, and will allow easy access. Spark plugs wire are then no longer an issue.

I cant see how the original placement of hoses, wires, are a problem with headers. Again, mine are coated, which has already shown a decrease in under hood temps from radiated heat, which may be the exception. Regardless, you do have to watch wire and hose placement. But 5"? maybe so....

Flareside

Sounds great Melvin. How is the quality of the Hedman coating?

Sorry, but I had to sell the tripower to someone else while you were away. Did you ever find one?

-Joe

ZORA_RULES

Sounds cool to me :cool:. I like my cerma coated hedmans too, over the crap ram horns...only I have a SB :(.

Sweet........love those 502s.