Hi guys looking at getting new headers as I hit a rock and tore a hole in 1 tube 4-6" a buddy says he can fix them but not happy with the Headman fit as the #3 and 5 plugs are super tight against tubes and burning the wires even with Accel shorty's ! What is the correct size to chose;stepped 1-3/4 to 1-7/8 or ?
383 header size ?
madcarson
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I am having the same trouble with burned wires on a 383. I purchased it and do not know the brand of headers but with the shorty Accel plugs #3 is right up aginst the header. I just replaced and rerouted the plug wires, gained tremendious power, don't know for how long.
gene68ss
gene68ss
I cut and paste the below from a previous post I made. It seems relevant.
"For anyone interested, I previously said I'd post results when I changed out headers. Okay, I know it's not a scientific comparison but I think it's pretty conclusive.
Last time out ran 11.65-67's in 2600-2800 DA. Before that ran some 11.60-11.64's in 2000-2300 DA.
Swapped out summit brand 1 5/8 inch headers for new Dynatech 1 3/4 stepped to 1 7/8. No other changes.
Ran 11.55-59 in 3100-3300 DA. Worst air of the year, new best time.
Previous best of 11.57 was run in about 1500-1800 DA.
I was a little worried they might be too big and hurt my et but wanted to give them a try. I think I can safely say they were worth at least a tenth and given the higher DA maybe .15
I'm very happy with the results, the Dynatechs fit and look awesome. Good ground clearance also. Your results may vary!
My previous best was 11.57 @ 115. I ran an 11.55 and 11.57 both at 115 with the new headers but in much worse air. Actually every pass was 115 mph. I'd been runnng 113-114 in the 11.60-67 range, depending on air.
60 ft's were right on par with a best of 1.60, same as before. I guess now I'll have to wait till the fall for some nice cool air and see what it'll do."
I hope this is real world enough for everyone. I was surprised actually, I don't have a high revving engine. I shift between 6000 and 6500.
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"For anyone interested, I previously said I'd post results when I changed out headers. Okay, I know it's not a scientific comparison but I think it's pretty conclusive.
Last time out ran 11.65-67's in 2600-2800 DA. Before that ran some 11.60-11.64's in 2000-2300 DA.
Swapped out summit brand 1 5/8 inch headers for new Dynatech 1 3/4 stepped to 1 7/8. No other changes.
Ran 11.55-59 in 3100-3300 DA. Worst air of the year, new best time.
Previous best of 11.57 was run in about 1500-1800 DA.
I was a little worried they might be too big and hurt my et but wanted to give them a try. I think I can safely say they were worth at least a tenth and given the higher DA maybe .15
I'm very happy with the results, the Dynatechs fit and look awesome. Good ground clearance also. Your results may vary!
My previous best was 11.57 @ 115. I ran an 11.55 and 11.57 both at 115 with the new headers but in much worse air. Actually every pass was 115 mph. I'd been runnng 113-114 in the 11.60-67 range, depending on air.
60 ft's were right on par with a best of 1.60, same as before. I guess now I'll have to wait till the fall for some nice cool air and see what it'll do."
I hope this is real world enough for everyone. I was surprised actually, I don't have a high revving engine. I shift between 6000 and 6500.
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How do these headers compare?
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hi ,guess you are getting lots of response from your post and may not need my $.25 but ill toss it in anyway!
i have 67 4spd with a 383 10.2:1,edelbrock perf rpm heads,intake,comp cams 276HR,pro mag rockers,750 demon. strong little street engine with nice manners.had full length 1 5/8 x3" hedmans they were ok. swapped on 1 3/4 x 3" hooker super comps and i could feel more power in mid range and higher rpm.......it still has more power than the tires can use if i mash it off idle.
also,as an aside.....if smaller tubes are better,why was my car faster with 3"x18" collector extentions and no mufflers compared to my full length 2 1/2 " magnaflow system? kinda wish i opted for the 3" kit but tech said i would lose power...... i think listen to everyone then do what YOU think is best...your car/cash
i have 67 4spd with a 383 10.2:1,edelbrock perf rpm heads,intake,comp cams 276HR,pro mag rockers,750 demon. strong little street engine with nice manners.had full length 1 5/8 x3" hedmans they were ok. swapped on 1 3/4 x 3" hooker super comps and i could feel more power in mid range and higher rpm.......it still has more power than the tires can use if i mash it off idle.
also,as an aside.....if smaller tubes are better,why was my car faster with 3"x18" collector extentions and no mufflers compared to my full length 2 1/2 " magnaflow system? kinda wish i opted for the 3" kit but tech said i would lose power...... i think listen to everyone then do what YOU think is best...your car/cash
hello Camaro world. I have a question about header size. ive built a 383 sbc , im using a dual plane intake, I have a quick fuel 750 cfm carb, 190cc 64cc aluminum heads, with stainless steel full rollers, cam is .488/.507 valve lift and DOD 289/297. I have 6.0 rods with probe pistons with negative 8.5 dish pistons. need help knowing what size headers to buy for this beast. please help. this is only the second engine ive built. newbe
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i have the dynotech 1 3/4 to 1 7/8 step headers on my nova. the fit is the best i have ever saw unless custom built for the car! it uses a stock sized starter with all kinds of room. they are nice and close to the floor as well. the ball and socket collectors are really nice too! the coated ones use Nitroplate coatings. very easy to keep looking nice.
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No offense Ono, but that article was written 11 years ago, and the NHRA class this guy is talking about is H/SA. Our stroker street motors today, with their much improved heads, are certainly much powerful than what was allowed in SE class racing.
1.5" tubes? No thanks.
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6,242 Posts
You realize that this thread is 4 years old and the article was only 7 years old at the time.
We're not talking about the heads - we're talking about the headers. Can you point to any significant improvement in Hooker headers since the 1970's? When were the 'improved' heads designed? H/SA cars in that time were 350" Camaros running 11.30's.
in an ideal world (and engine design) headers would be on the conservative side. but sometimes the car will be faster with the bigger header, weather its because its light or have a bunch of stall or its just a bandaid fix for another issue.
Ford Cleveland engines usually like large headers... why?
maybe because the intake side and valve size work very well, but the exhaust port isn't so good, and the larger header is a bandaid fix for it.
peak HP should also be a consideration when choosing headers,
a 450hp SB isn't going to be using the same header as a 600hp SB.
my 420sb picked up over 1mph going from 1 3/4" to 1 7/8" headers
but the opposite would be true if I did that to my 383.
Ford Cleveland engines usually like large headers... why?
maybe because the intake side and valve size work very well, but the exhaust port isn't so good, and the larger header is a bandaid fix for it.
peak HP should also be a consideration when choosing headers,
a 450hp SB isn't going to be using the same header as a 600hp SB.
my 420sb picked up over 1mph going from 1 3/4" to 1 7/8" headers
but the opposite would be true if I did that to my 383.
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In the last 10 years or so, heads have improved dramatically. It used to be, 186 GM castings (or other double-humps) were the ticket and hard to find at a reasonable price. Now you can find them for a song.
Why? Because aftermarket offerings from AFR, Dart, Brodix, etc, will out-flow the best GM castings by 15 to 30% or more. It makes sense that the exhaust requirements will change dramatically with improved flow and improved exhaust ports.
The OP doesn't have a 350. He has a 383. Nobody would recommend 1-1/2" tubes on even a mildly built 383.
From here (some guy named Lingenfelter):
http://books.google.com/books?id=GU...QCQ&ved=0CDMQ6AEwBg#v=onepage&q=header diameter small block chevy chart&f=false
...is a chart that shows his recommendation for a 383 at modest 400 HP. He says 1-3/4" tubes are best.
FWIW
at only 400hp, you could run 1 5/8", even on a 383 thats got a bit more piston speed. I bet on a low rpm / low hp deal like that the diff between 1 5/8" and 1 3/4" would be a wash.
the other thing is... what are you lookin for.
if its a car that you want to 60fts hard, the smaller header may help at the expense of mph.
and the larger header should mph better but may not 60ft as well.
and you aint gonna 60ft nothin on the street, so I'll take the bigger header and the mph in a streetcar anyday.
the other thing is... what are you lookin for.
if its a car that you want to 60fts hard, the smaller header may help at the expense of mph.
and the larger header should mph better but may not 60ft as well.
and you aint gonna 60ft nothin on the street, so I'll take the bigger header and the mph in a streetcar anyday.
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