Big thumbs up to MAC mid's
 

Help my buddy install a set of MACs on his 99 SS last night,and i just wanna say that I am very impressed with them.He got them off of ebay for i think just over $400 for the headers,y pipe,and hardware.They had a very nice silver finish on them,dont know if it was an option or not but they were gorgeous.The install took us about 6 hours to do from start to finish,mainly due to the fact that we could not for our lives get the driver side header up and in.ended up taking the coil packs off as a complete unit on the driver side to get the header up and then back down and in,and unbolted all the bolts on the pass side coil pack rail so we could swing it out of the way for a bit more room.also ended up cutting off that piece of the block on the pass side that gets in the way.luckily we read about that earlier before we started the project or else we woulda been ef'in clueless :confused: .
i almost cant wait to do them again now that i know what im doing.i think that me and the other 3 people that helped on the car could easily get a set installed in 4 hours,if not less.i already have a 98 Z28 that im going to end up doing them on,and as soon as i get my car ill definetely be getting some MACs.so we'll see.oh yeah and the exhaust system is a flowmaster american thunder,and it sounds SWEEEEEEEET.there isnt a single thing that sounds better than american muscle flowing through a flowmaster :usa:

Yes, MAC's are great headers and a breeze to install.

Oh, and Flowmaster is CRAP. It has the worst flow numbers of any cat-back system for our cars. Sounds great, yes, but you won't be seeing the full potential of the headers with Flowmaster (aka: Crapmaster, Chokemaster, etc...)

ive been reading about how flowmaster supposedly has some pretty crappy flow characteristics.are there any track/dyno numbers out there to prove it though??and are you talking about flowmasters product line as a whole or just their american thunder system?and if its only like 10hp or so i personally wouldnt care because i love the sound so much,and the kid who owns the car we did the install on doesnt give a rats ass really.his cars' purpose is mainly to look damn good(which it does)and sound damn good(which it most definetely does).he drives it only here and there,and he drives it like its a regular car for the most part.

The flowmaster thing has been proven again and again.

The Mac headers used to be a great bang-for-buck header. My heads and cam combo put down 447/409 through modded Macs (no ball flange) and a single 3.5" collector. I'd like to add that after upgrading to Jet-Hots and dual cutouts I gained 1.8mph. Never dyno'd it.

Just the crossflow design Flowmaster muffler is crap, which is the one for our cars. I had it, and yes it sounds great, but others sound better IMO. I have seen flow numbers for various cat-backs and IIRC, Flows was 300 CFM, while the Loudmouth was around 1600 CFM. Borla was like 800 CFM, I think... There are better exhausts than Flowmaster. If you are doing headers you are probably looking for SOME power gain, so I'm just saying Flows may be holding back the potential of your motor.

How do you even compare the mac's to the jet-hots when you also installed dual cutouts? what did you run with your cutout closed :huh:

Yeah, those cutouts would have helped quite a bit to that 1.8 MPH you gained. By how much, who knows. MACs are not crappy headers like some people like to think

I never said all of my mph gain was from the headers, I simply stated the difference between the two setups. Here's the difference, make your own conclusions.

Heads/cam ~3800lb Camaro :emb: , Macs, 3" ORY with a 3.5" flowmaster collector, open 3.5" cutout right after the Y. 118.2 mph

Same car, but with Jet-Hots and dual cut-outs: 120 mph

Don't worry it makes sense but look at your Torque and HP curve and you'll find them different.
The gain of LT's increases as power adders go on but the Macs are great for street/strip set up. No clearance problems, no banging especially with lowered cars. It's like comparing oranges and mandarines, same species, different taste.

i had macs and i liked them,i don't think they are a bad set of headers at all. i just switched to kooks a pain in the azz to install,(driver side)but i'm trying to squeez every last drop of power from my car,and the kooks have a nicer sound too.

I will be honest I have a flowmaster on my car, it sounds great over the stock muffler, that's why I got it. But I went to a Tenneco automotive class on Monday and they are the people who make Monroe shocks and struts and Walker and Dynomax exhaust systems among other products. They had a Dodge Truck that was on two ramps on the right side, we didn't know at first why the dodge had dual exhaust and one pipe coming out the right side, but that was when the instructor started to put on different mufflers on this pipe so we could hear them. Also had cutaways of all major types of mufflers and the Flowmaster had flow that is only like 150cfm over a generic turbo muffler, the dynomax was pushing almost 1000cfm nearly twice that of a stock muffler, and it was a straight shot from inlet to outlet. I was fairly impressed, But they didn't say anything about Magnaflow( which I most likely will be getting after my Jethots) But still wouldn't put their struts or shocks on my car, mom's car absolutley, mine no. Just some info, sorry so long

since mac's are midlengths and dont extend down as far, can you still put an x pipe on them?

you bet ya can check out this thread ;)
https://ls1tech.com/forums/generation-iii-external-engine/157723-mac-headers-3-inch-x-pipe-pics.html

The Macs are great. My car can vary up to 4 mph due to weather, so you cant compare the 118 to 120 unless the weather was pretty much ideal Also, how do you get a 3800# camaro? Convertible? My 00SS fully loaded with every option incl T-tops was 3450.It would take a 350# dude to make 3800! :confused:

9", roll-bar, and driver, no weight reduction.