MAC headers and Y-Pipe?
Thread Starter
Teching In
Joined: Nov 2008
Posts: 25
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MAC headers and Y-Pipe? what are your thoughts on this set up? are they any good? Ive been told that my car is too low to have other longtubes and that these will be perfect and will not hit the ground.are they any good?
Adding a Flowmaster collector to the Y goes a long way in eliminating the rasp you refer to. I did it when I had the MAC's and it sounded good. The MAC's tuck pretty good under the floorpan for lowered cars.
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I had them on our show car for a long time and liked them a lot. They tuck up really nice and made very good power.
Mac only makes the off-road version so what we did was weld in a set of Random tech high flow cats which worked really well.
If you need a set, we can set you up with a great price!
Mac only makes the off-road version so what we did was weld in a set of Random tech high flow cats which worked really well.
If you need a set, we can set you up with a great price!
I run Mac mids but they have been modified at the collector with the three bolt setup instead of the ball style connector, suppose to flow better. The ORY has a Flowmaster merge going to a 3" 1 chamber Flowmaster in the stock location with a dump. Sounds real good and doesnt scrape anything. 
People will bash them because they will make maybe 5-10hp less than a long tube. 
People will bash them because they will make maybe 5-10hp less than a long tube. I run Mac mids but they have been modified at the collector with the three bolt setup instead of the ball style connector, suppose to flow better. The ORY has a Flowmaster merge going to a 3" 1 chamber Flowmaster in the stock location with a dump. Sounds real good and doesnt scrape anything. People will bash them because they will make maybe 5-10hp less than a long tube.
People will bash them because they will make maybe 5-10hp less than a long tube. The Macs are a good header. Long tubes are still better but if you want something that tucks up really nice, installs easy and doesn't hit the floor, they are tough to beat.
I've been selling LS1 parts for 10 years now. I remember when the die hard racers switched from Macs to Long Tubes and only dynoed 5-7 HP extra and how pissed they were.
The Macs are a good header. Long tubes are still better but if you want something that tucks up really nice, installs easy and doesn't hit the floor, they are tough to beat.
The Macs are a good header. Long tubes are still better but if you want something that tucks up really nice, installs easy and doesn't hit the floor, they are tough to beat.
Bout time there are more people posting FOR mac headers than bashing them!
My car in sig made 399RWHP through mac mids and ORY, there's a build thread and dyno sheet around here somewhere.
You can also port the lip out of the primaries where they meet the motor. Opens up the header a good bit. Another little trick we used to do back in the day when longtubes weren't around yet.
Teching In
Joined: Apr 2008
Posts: 4
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From: Grayslake, IL
I installed a set up Mac's with the catted y-pipe this summer. I have a FM muffler and I think it sounds great, however there is a lot of interior drone, especially with the windows up. For that reason I will probably be changing the muffler out. My install was a PITA but it sounds like everyone's experience is different. I also have a the dreaded y-pipe rattle since it is bumping up to the driver side floor board. I'll need to get that bent this spring.
I installed a set up Mac's with the catted y-pipe this summer. I have a FM muffler and I think it sounds great, however there is a lot of interior drone, especially with the windows up. For that reason I will probably be changing the muffler out. My install was a PITA but it sounds like everyone's experience is different. I also have a the dreaded y-pipe rattle since it is bumping up to the driver side floor board. I'll need to get that bent this spring.
def the flowmasters. i already had an slp magnamouth catback and just installed the macs with catted y and the car is no louder than before. sounds slightly better than before but not any louder. might be slightly quieter at idle and slightly louder at WOT but almost no difference.