headers or manifolds ?
#1
headers or manifolds ?
so I finally got my 355 dropped into my 86 irocz and am now finidng out what a bitch the exhaust is going to be, I purchased some full length hedman hedders that said they were for 3rd gens but they don't fit and I can't return them because I used them on the test stand to fire my motor, I've tried the center dump corvette ram horn manifolds and shorty center dump headers that hug the block and neither of them fit, so where I'm at now is: I can get a hold of some z28 manifolds for free or I can put down another $150 for some shorty headers, which would be the better thing to do ?
it's a pretty hot little 355, 510/510 lift 244/244 at 050 cam, 10.5-1 pistons, bowl blended vortec heads, rpm air gap intake manifold and a 750 double pumper, probably around the 400-420hp range, I would love headers but will the shortys for the 3rd gen fit for sure, and will they be leaps and bounds better than the z28 manifolds ?
it's a pretty hot little 355, 510/510 lift 244/244 at 050 cam, 10.5-1 pistons, bowl blended vortec heads, rpm air gap intake manifold and a 750 double pumper, probably around the 400-420hp range, I would love headers but will the shortys for the 3rd gen fit for sure, and will they be leaps and bounds better than the z28 manifolds ?
#2
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Car: 86 TA, 91 B4C
Engine: 5.3, 4.8
Transmission: 4L80 4000, T56
Axle/Gears: 4.30 M12, 23.42 10 bolt
Re: headers or manifolds ?
If they were made for your application then you mean they wont drop in? My headmans went in from the bottom.
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Car: 86 TA, 91 B4C
Engine: 5.3, 4.8
Transmission: 4L80 4000, T56
Axle/Gears: 4.30 M12, 23.42 10 bolt
Re: headers or manifolds ?
Yea, i had that problem, i just "adjusted" where necessary with a hemmer. They work fine now.
#5
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Car: 1984 T/A
Engine: Chevrolet 355
Transmission: Borg Warner
Re: headers or manifolds ?
Don't use the manifolds, they will restrict the flow and power (especially considering you are over 400hp). Try the hammer first, if that does not work move on to another set of headers.
#6
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Car: 88 IROC, 76 Malibu Classic
Engine: 350 TPI, 350
Transmission: 700R4, 4-speed
Axle/Gears: 10 bolt ????
Re: headers or manifolds ?
400-420 on 750 double pumpers? thats being pretty modest. i'd say near 475 is more realistic.
#7
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Car: 88 Camaro
Engine: 355
Transmission: TH-350
Re: headers or manifolds ?
When I had heddman's I had to do some clearancing myself even though I bought brand new motor mounts....So, like already stated use a BMFH!!
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#8
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Car: 1987 Firebird
Engine: 355
Transmission: T56
Re: headers or manifolds ?
Go with the headers. Use the hammer, get er in there. Its a BIG difference.
You can always recover your cost by selling those huggers you bought, everyone is always looking for headers.
You can always recover your cost by selling those huggers you bought, everyone is always looking for headers.
#9
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Car: 92 Convertible 25th Anniversary z28
Engine: Tune Port Injected 305
Transmission: 700R4 with 2200 stall
Axle/Gears: 3:42 with new posi unit
Re: headers or manifolds ?
I have a 1992 z28 and I have hooker super competition headers on it. They are shaped really funny but they fit. And mine went in from the bottom too. The only problem I was having with mine was it kept burning up plug wires which small block chevy's with headers are notorious for doing. I went to a speed shop here in town and ordered some header plugs which are just a really short spark plug and it pulls the boots back from the headers. They were about $30 for 8 but that fixed the problem.
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Car: 88 Camaro
Engine: 355
Transmission: TH-350
Re: headers or manifolds ?
I have a 1992 z28 and I have hooker super competition headers on it. They are shaped really funny but they fit. And mine went in from the bottom too. The only problem I was having with mine was it kept burning up plug wires which small block chevy's with headers are notorious for doing. I went to a speed shop here in town and ordered some header plugs which are just a really short spark plug and it pulls the boots back from the headers. They were about $30 for 8 but that fixed the problem.
What plugs were you running? I run super comps and I run standard length plugs with out issue? Just curious...
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Car: 92 Convertible 25th Anniversary z28
Engine: Tune Port Injected 305
Transmission: 700R4 with 2200 stall
Axle/Gears: 3:42 with new posi unit
Re: headers or manifolds ?
you know i dont really remember that was so long ago. but i dont know what the deal was but my headers loved to eat the wires on plugs 4 and 6 constantly. it might also had to do with me running cheaper wires or something I have no idea. Im running taylor wires now and the header plugs so I should be good.
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