headers are a pain!
 

2 weeks ago I bought a used set of MAC equal length headers for $25 bucks! Crome and in good cond. Well 2 weeks later I am still trying to install them. I got the drivers side in ok, but the passenger side header tubing doesn't line up right with the exaust ports in the head. I've been using a pry bar trying to get some luck threading the bolts in. I think I'm going to have the car towed into the shop I work at and fixed. Anyone know how much HP gain i should get with these headers? My car is bone stock besides a K&N air filter.

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90 Mustang GT. K&N air filter, completely stock. Purchased at 107,000 for $3500

Ahhhh exhaust work ya gotta love it..

Have you tried loosening the motor mounts,then jacking the motor up so you have more room to work with them?

I had to do this with my Mac 1 5/8 long tube headers,they went on without a problem after I jacked it up and slid the headers up from underneath(of course you won't have to do this http://www.mustangworks.com/msgboard/smile.gif

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Paxton Blown 87GT
ICQ#91504337

I'm not too sure on the gains (maybe 10-15hp), but I know what your talking about as far as threading the bolts. I just put another motor in my 86 mustang a few weeks ago and had problems with both headers. If I came to a set of bolts that wouldn't thread, I took the bolts out that I had already threaded and started at a different pipe. I had to use a prybar to flex some of the pipes, but I eventually got the bolts in.

yeah, what a pain that was... I considered switching to equal lengths, then said "forget it!"
Good luck man, we feel your pain! http://www.mustangworks.com/msgboard/smile.gif

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Joe!
1988 GT, 167,000 miles!!! 13.58@105mph Check out my listing! Click here! Or my website:
www.joe4speed.com
1999 Ninja ZX-6R 10.32@135mph!
1993 Olds Eighty Eight LSS 16.40@88.8mph

If those are the 1 5/8" equal lengths, I hate to be the bearer of bad news, but I wouldn't expect more than 5hp.

Your car doesn't need the extra flow that the equals will provide, and they'll rob a good deal of low end torque.

Honestly until you get some mods, you'll be much better off with the stockers. Even though they look like *** , they are not the bottleneck you want to address in the exhuast. That is your factory H-pipe. Swapping that with a hiflow unit could net you an honest 15hp.

...ditto

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88 Notch, 3.73's, Ported E7's, Explorer int. w/ ported lower, pulleys, 1.7RR's, BBK headers, off-road H-pipe, flowmasters, subframe connectors, 65mm TB, shift kit, March ram air ,MSD coil, U/L control arms, 155lph fuel pump, cheap 2800 stall, Crane Adj.FPR, best 1/4--> 13.77@101.35

Just drive it to the muffler shop with it open. No need to tow it. It'll run a little ruff and not really go anywhere but you'll get there. Thats what my friend did when he couldn't make the piping line up. As for me I've done it a couple of times already.

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67'fastback-Edelbrock carb,intake,cam,valve springs.Rhode lifters, CompCam rocker arms, windage tray,cerama coated headers,dual flows with H-pipe, modded c-4,tci stall converter,perma cool electric fan,aluminum water pump,griffen aluminum radiator,accel 8.8 cable,wide cap distriburator,magnetic pick up,v-matic hurst shifter,edelbrock performer nitrous, carter electric fuel pump,ignitor coil,solid motor mounts,magna racing suspension,poly urathane bushings,under rider traction bars, comp. eng. s

Do they have a one-piece flange? If so then hack off the bottom corner of the front bolt hole and the very back bolt hole, so they are in the shape of a "C" with the open part facing down. Put those two header bolts into the head and place the header onto these two and then start up the other bolts.

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GT-40 heads (ported, polished, + milled), B303 cam, 1.7rr's, JE pistons, Offy intake, Carter AFB 625cfm carb, Flowtech 1 5/8" shortys, Flowtech X-pipe, MAC Flowpath exhaust, MAC pulleys, 373's, subframes, Eibachs+Tokicos, B&M ripper, FMS Clutch, Zoom Quadrant+cable, 17" CSA Ultra rims, 235/45ZR17 Yokohama AVS S4's, MSD 6A ignition+coil, FMS 9mm wires, Carbed, Naturally Aspirated, and Nasty!

I am having the exact same problem you are red_90_gt. It sucks bad. My passanger side lined up fine, but the driver side won't line up perfectly!!!!! Headers F*&%ing suck!!!!!!!

I just put on a used set of mac equal length shorties and really didn't have and problems. On the passnger side, I had to lift the motor a few inches, and I just got rid of the air pump tube that went to the h-pipes. Other than that, there was really no problems. Did you buy new bolts, or use the old ones?

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89 black GT, 5 spd
flex-a-lite electric fan
flowmaster cat-back + h-pipe
1 5/8 equal length shorty headers
MSD Blaster coil