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Old Oct 18, 2003 | 08:41 AM
  #1  
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Default Mac midlengths

Hey guys I wanted some info on mac midlengths, what kind of power gains are yall seein, do they fit good etx. Thanks for the info.

WeS
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Old Oct 18, 2003 | 09:14 AM
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Default Re: Mac midlengths

Read the Nov. Car Craft issue on header's,very interesting.Shortie's and midlength's gained over 20hp over LT's with a slightly higher torque peak.
I'm thinking about them for the fact they may be perfect for a street tire car because they may kill the TQ down low to help not to blow the tire's off and pull harder on top.I have seen almost all good review's on them but their still seen as header's bastard son.
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Old Oct 18, 2003 | 09:25 AM
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Default Re: Mac midlengths

Why would they kill low end torque? I would of thought they would make more low ene than LTs.
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Old Oct 18, 2003 | 10:18 AM
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Default Re: Mac midlengths

thats what i would think too. Maybe i'm way off but i always figured shorties and midlenghts for the low end torque, and a few hp, and LT's for the big hp gains??? anyone got any input on this?? thanks
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Old Oct 18, 2003 | 12:25 PM
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Default Re: Mac midlengths

The longer the tube, the more low end torque (to a point). Also smaller dia (1 5/8) tubes will add some lowend grunt, but sacrifice the top end.

The Macs are short 1 3/4" headers. I would think that they would make good top end, but lack on the bottom end.

Also I understand that the header flanges need to be opened up to flow good, and the ball end (reduces down to 2.5) needs to be replaced with a straight 3" collector to eliminate flow restrictions.

Hey I happen to have a set of 98-99 macs I would like to sell. They are brand new. PM if intrested.
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Old Oct 18, 2003 | 12:34 PM
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Default Re: Mac midlengths

I have mac midlenghts and they work perfectly for me. Check sig. Also, my friend has gone 10.50's on 150 shot with H/C with those same headers and same YPipe, a cutout and a bullet muffler.

So they are the best bang for the buck IMO.

FWIW: When I was running 13.70's I added 373 Gears and those headers and ran 13.0's all night long.
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Old Oct 18, 2003 | 05:41 PM
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Default Re: Mac midlengths

ok, i have a question then. I know everyone says how much shorties suck, but, what about the new BBK's? they are 1-3/4 like the LT's, every other shorty header is a 1-5/8. Would this make a difference? I talked to the tech at TBYRNE and they told me that shorties are worthless on a '01-'02, but the BBK's would show a hp increase especially since i would be pairing it up with a Random Tech Y-pipe with hi-flow cats and LM cat back. just trying to get some more feedback, thanks guys
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Old Oct 18, 2003 | 06:18 PM
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Default Re: Mac midlengths

macs may claim 1 3/4 primaries but they are only 1.45"

http://www.ls1howto.com/infopics/macs_and_flps.jpg

my macs killed my cam...i got pacesetter LT on the way
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Old Oct 19, 2003 | 12:46 AM
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Default Re: Mac midlengths

In the CC article TQ was down slightly with mid's but the peak was higher then LT's.I think the mid's made like 23hp over the LT's at the top. I remember a header test a few yr's back and the guy's who ran it were dumbfounded that the shortie's beat out LT's in peak HP.
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Old Oct 19, 2003 | 01:17 AM
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Default Re: Mac midlengths

I'd just follow all the big boys on this site and get long tubes..but not SLP ..the #s are shitty with those ..save and get some KOOKS, QTP, FLP (although fitment seems to be a problem for some), JETHOT, or a very popular mid priced long tube is HOOKER headers.
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Old Oct 19, 2003 | 01:25 AM
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Default Re: Mac midlengths

In the CC article TQ was down slightly with mid's but the peak was higher then LT's.I think the mid's made like 23hp over the LT's at the top. I remember a header test a few yr's back and the guy's who ran it were dumbfounded that the shortie's beat out LT's in peak HP.
id be very interested to see this...as far as i know theres only one member who LOST hp by going from macs to LT..

and ANOTHER member got like 18whp with LT over macs..
i can tell you i have macs now and they are KILLING my MTI X1.. cant wait to swap em out...but very good headers for a non internal car
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Old Oct 19, 2003 | 08:19 AM
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Default Re: Mac midlengths

I bought Macs because I am on a budget. I think the price of some LT are obsene.

Anyway, I think my Macs are great, BUT I would buy hooker LTs since they are now available if I had to do it all over. (They didn't exist when I installed my headers)

Tommy
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Old Oct 19, 2003 | 02:01 PM
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Default Re: Mac midlengths

I just installed my mac's like 2 weeks ago I like them they can get poppy when u decelerate. But I was able to install both headers from the top.
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Old Oct 19, 2003 | 03:22 PM
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Default Re: Mac midlengths

I just installed my mac's like 2 weeks ago I like them they can get poppy when u decelerate. But I was able to install both headers from the top.
I bought my Macs ceramic coated to save over flp's inflated price's. Hookers were just coming out when I put the engine in but did not have a y-pipe yet and I did not want a butcherd pipe from a local shop. I am curious to see what gains could be had with long tubes but I have ran some vey impressive times for a full weight fully loaded trans am. I can make up for low end tq when I put 4.30 gears in soon.
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Old Oct 19, 2003 | 04:19 PM
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Default Re: Mac midlengths

Before my H/C swap, I was running shorties WO/cats + Y + Hooker CB. I had decent # 343rhp. Let us not forget that shorties are designed to run on SI. I would think that Mid Length would be good with up to 220/224 cams, but higher duration would require LTs.
I now run Paces and the gain over the shorties are way noticeable especialy on top.
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Old Oct 21, 2003 | 04:48 PM
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Default Re: Mac midlengths

I think I will purchase MACS, b/c from what ive heard they are good with the stock motor.
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Old Oct 22, 2003 | 08:20 AM
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Default Re: Mac midlengths

I made 30rwhp with MACs (through factory cats) and the LS6 intake on a stock engine. Figure at least 18+rwhp of that was the headers. Great SOTP feel and an easy install with no clearance problems. As been mentioned, the collector could use some work and some of the welds needed grinding, but both headers dropped in from the top no problem. I've upgraded to LTs now that I have heads and a big cam, but reccommend MACs 100% for a bolt-on car. They are really cheap used...hell, I have a set in my garage for cheap.
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