so i've been mulling headers for a few years now and i'm close to getting MAC's. i'm still nervous about doing this mod as so many have told of horror stories with header install. i did roller rockers/new valve springs last year and i have some basic tools.

so should i do this thing or not? i will be getting them ceramic coated and i i'll be using a cat.

some additional questions:

1) will new ac/delco plugs wires work in stock locations with MAC? this will be the first time doing plugs so i'll need instructions on how to gap etc.
2) what tools other than a basic ratchet set do i need?
3) will i be able to use my stock cat? if not, can a new cat be bolted on or must it be welded to y-pipe?
4) will i need to jack up the motor (have no idea how to do this)
5) do i need any heat shields, and heat-sleeves for protecting wires. if so where do i get these?
6) what head bolts and gaskets to use?
7) how much hp/tq will this add to my car? how much total hp (see existing mods) will adding MAC's bring me to?

if i forgot anything please let me know....thanks guys.

 

The Macs have great spark plug clearance! I like the Accel 9000 wires; they stand up great to heat and might be cheaper than a set on new Delco wires. No heat shields or heat sleaves required. I don't think you'll need to jack up the engine to install. You will need to retorque the header bolts after a few thermal cycles to make sure the bolts don't come loose.

 

thanks for the info. i already have a new spare set of ac delco wires i plan on using. good to know i won't need heat sheilds/sleeves, or jack up the engine.

 

Your cat is welded to the stock Y-pipe. If it's the stock cat, it's probably due to be changed anyway. The challenge is that you'll need to tow or drive your car to an exhaust shop to get the cat welded to your new Y-pipe.

Probably a good idea to install new O2 sensors too.

 

yes, i did forget about o2 sensors. so is there no cat that can be bolted to the mac y-pipe?

 

You can have a muffler shop weld a flange onto both your Y-pipe and cat; usually you want this done on the car to maks sure everything lines up properly to give you max ground clearance.

 

i had to drive to the muffler shop about 15 min away with just the headers bolted up to get my ypipe/offroad piped welded up.. .sounded MEAN!! hehehe

to the original poster, you will also need a short wrench to put the header bolts on.. i wasnt able to use a ratchet. i used 1" black oxide arp bolts and oem multi-layer steel gasket and havent had any issues with bolts backing out or leaks.

 

i see what you mean...i would really prefer to do this on my own if i can. maybe i can line everything up and mark the areas that s/b in line with one another and take the pipe and cat off and have them weld it. all along i was thinking that the new cat w/b able to be bolted up. what about a u-clamp or something to attach the y to the cat?? would that work?

 

The y-pipe that comes with the MAC mids will bolt directly to a stock cat. If your going to replace the cat with an aftermarket one, you will need to have flanges weld on to bolt up to y-pipe.

 

that's what i really wanted to hear. my car only has 69k unabused miles so i'm pretty sure my cat is fine. i will keep the stock cat and saw it off with some extension so the mac y-pipe fits over it.

do you guys have any feedback on the other questions:

1) will new ac/delco plugs wires work in stock locations with MAC? this will be the first time doing plugs so i'll need instructions on how to gap etc.
2) what tools other than a basic ratchet set do i need?
6) what head bolts and gaskets to use?
7) how much hp/tq will this add to my car? how much total hp (see existing mods) will adding MAC's bring me to?

 

Where can you find the MAC mids coated? Im also interested in buying a set. They seem to be the best emissions legal header out there from all the searches I have done. Foxbat, upon searching it seemed most people were getting like ~20 rwhp.

 

I am about to do some pacesetter long tubes comming up shortly. But you should look at it this way. It is all just a bunch of nuts and bolts. All you have to do is find creative ways to get them on and off.

 

I dont know if this would apply to you since your car only has 69k unabused miles. But when I did my Macs I had to replace my motor mounts because the headers would not fit. So I had to wait an extra week to finish the install. The Macs are very nice headers and as previously stated have excellent plug clearance.

The install itself is a royal PITA, but very well worth it. I am not completely sure on the hp/torque numbers, but after the headers and catback it felt like a totally different car.

Stock wires will work, but OVC wires are really nice. I went with Felpro gaskets and Breslin bolts and they worked great, I have had no problems.

 

I had a shop install my Mac's. I have ZERO tools (except Duct Tape & Vise-Grips!) and ZERO skills to do any work myself. The plug clearance is MUCH better. As far as the HP/TQ gains.....i had mine dyno's after the install....if I remember correctly (it was like 3-4 years ago) I picked up 21 PEAK HP (13 avg) and 31 PEAK TQ (17 avg). Mine was a VERY expensive mod for me since I didn't do it myself. With the headers, ceramic chrome coating & install was like $1000+/-. The sound was nice and it DEFINATELY had a nice SOTP improvement! I also picked up about .2 in the 1/4 mile. Hope that helps.
Mike

 

The MAC Y-Pipe is flanged, and the headers come with a "starter pipe" to weld to your cat. I have both set-ups. A bolt-on cat, and a MAC off road pipe. I can swap between the 2 in about 20 minutes. I also have my cut-out welded in my off road pipe.
I chose to keep my car emissions legal for Maryland, so the headers still have the A.I.R. and EGR hooked up. With the cat on the car it passed Md's "treadmill dyno" emissions test with the ported heads and CC305 combination.

Spark plug access is great.

Performance? Stock 94,000 mile bottom end, ported LT1 castings, and tiny CC305 went 12.0 @ 112 MPH with a 1.67 60 ft. time. Full weight car with completely stock suspension.

Frank