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Pros Cons of Headers

I'm going back to a factory exhaust manifold when my current headers go bad...of course I am restoring to stock as best I can, but to tell you the truth it's a lot louder than I like with the headers.
 
So can I get something that bolts to my stock manifolds that gets larger to 3 inch to start a 3 inch pipe there?
 
Stepping it up to 3" will not do much if anything unless you do headers first. Dual 2 1/2" will be plenty for a mild big block. A single 3" will outflow dual 2 1/2's too. If you go with headers get a good set of wire looms and take your time running the wires. In 25 years and a bunch of vehicles with headers I have only burned 1 plug wire and it was my fault. I never wrapped the headers or used covers on the wires either.

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For your plug wire melting/burning probs use a set of moroso plug wire covers, speedway motors sells all types and all brands of covers at real good prices. I used em and will always, its nice to not to worry about a good set of 100.00 wires.

I have headman non coated headers here in the rust belt....lol and there 3 years old and in good shape, they just look crappy but its not a show truck for no means. The ball and socket for the collectors is nice but buy a set of steel lock nuts if you do. The nuts they come with you always have to tighten if you offroad, the double nut idea doesnt work. A good set of locking headerbolts is a good idea too as mentioned.

As said 3 inch is prob too much for a stock motor, 2.5 would be good. I have a set of headmans as said that have 1 5/8 flow tubes with 3 inch collectors and 3inch pipe connected to flowmaster super 44s. Its loud and has a different sound to it but my 350 is pretty done up. i should of went to a nice set of magnaflow mufflers.
 
Adventurous 4x4 said:
Stepping it up to 3" will not do much if anything unless you do headers first. Dual 2 1/2" will be plenty for a mild big block. A single 3" will outflow dual 2 1/2's too. If you go with headers get a good set of wire looms and take your time running the wires. In 25 years and a bunch of vehicles with headers I have only burned 1 plug wire and it was my fault. I never wrapped the headers or used covers on the wires either.
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Alright, I agree with everything there, except the bolded part. The area of the sectional ID of a 2.5" OD (16 ga) pipe is 4.4 sq in, so twice that would be 8.8 sq in. A area of the ID of a 3" OD (16 ga) pipe is 6.5 sq in. So dual 2.5" is still better than a single 3" by 35%. However, a 3" pipe alone is 47% better than a single 2.5" pipe. So a 3" is a big step up, 20% larger pipe gives you 47% better flow area. But dual 2 1/4" is still slightly better than a single 3". There is more frictional surface area of the two smaller pipes vs the one larger one however.

As for headers, I have always liked Hooker headers. They are the best quality bang for the buck most of the time. I had them with my small block, and I bought the same thing (Hooker comps) for my big block in my truck. I also still have a pair running in my car that are 14 years old. I would put them on again no doubt about it. They sound better too with a good quality muffler. Manifolds sound too choked, headers sound free, even through a nice muffled exhaust.
 
I have an old set of Doug Thorley Tri-Y headers on my 85 K30 Dually with a 454. The typical problems I have had are

1. excessive under hood heat because they are not wrapped

2. Starter motor heat absorption (cured by installing a starter motor heat shield)

3. The collectors hitting against the rearward front spring shackles when hitting large bumps.

The spark plug wires I am using are a set of Summit 8mm wires that have boots, which can be bent to any degree angle needed from straight to 90 degree. I was thinking of one day getting rid of these headers, and getting a set of mid-length headers, which are wrapped. This could solve some of the problems I have encountered.
 
Hey Wayne, thats a good looking engine compartment you have there. bet it took a while to get it nice and clean like that.
 
folkenheath said:
Alright, I agree with everything there, except the bolded part. The area of the sectional ID of a 2.5" OD (16 ga) pipe is 4.4 sq in, so twice that would be 8.8 sq in. A area of the ID of a 3" OD (16 ga) pipe is 6.5 sq in. So dual 2.5" is still better than a single 3" by 35%. However, a 3" pipe alone is 47% better than a single 2.5" pipe. So a 3" is a big step up, 20% larger pipe gives you 47% better flow area. But dual 2 1/4" is still slightly better than a single 3". There is more frictional surface area of the two smaller pipes vs the one larger one however.

As for headers, I have always liked Hooker headers. They are the best quality bang for the buck most of the time. I had them with my small block, and I bought the same thing (Hooker comps) for my big block in my truck. I also still have a pair running in my car that are 14 years old. I would put them on again no doubt about it. They sound better too with a good quality muffler. Manifolds sound too choked, headers sound free, even through a nice muffled exhaust.
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I didn't believe it either because of the numbers. I don't remember what company did the testing because it was way back in the 80's or early 90's. All I remember is on a mild street engine the single 3" flowed better. I don't even remember all the details but there were some varibles.
 
So you are saying on a previous test with a mild small block they got more power from a single 3"?...that may be possible.

Your engine does look clean by the way, he's right, nice job.

FYI, I'll probably be calling you guys again later this winter for more coilovers.
 
folkenheath said:
So you are saying on a previous test with a mild small block they got more power from a single 3"?...that may be possible.

Your engine does look clean by the way, he's right, nice job.

FYI, I'll probably be calling you guys again later this winter for more coilovers.
Click to expand...

I honestly don't remember the power numbers. It was flow numbers. IIRC they came off of stock manifolds not headers. It was a long time ago and I don't remember all the details.

Thanks again.

Give us a call. I will be getting coilovers or air shocks for the back of mine too.
 
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