Will these headers fit gt40p's (pic)

Lawbreaker5.0

Member
Feb 20, 2009
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Texas
so a guy is selling some NO NAME headers and H pipe locally. He thinks they are macs long tubes and i've been told that mac never stamps their headers so there's really no way to tell. Can anyone look at this picture and determine if they'll fit on GT40p's. This guy doesn't live that close 1 hour each way so i don't want to waste my time to drive out there if they won't fit. I would take the heads to make sure.

thanks.

pictureoflongtubeheaders.jpg
 
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looks liek they are mac's. if they are they will.. beside the fact, they do look like they will, pretty much any sbf headers will work with the p heads you just have to get creative with the plug wires..

MAC makes a set of shorty headers that are p specific but that doesnt mean any MAC header fits the p heads. Most headers wont work with p heads, most headers either sit on the actual spark plug or sit on the spark plug boot not the wire, even with a 90* boot there's not much you can do.
 
so a guy is selling some NO NAME headers and H pipe locally. He thinks they are macs long tubes and i've been told that mac never stamps their headers so there's really no way to tell. Can anyone look at this picture and determine if they'll fit on GT40p's. This guy doesn't live that close 1 hour each way so i don't want to waste my time to drive out there if they won't fit. I would take the heads to make sure.

thanks.

I have mac shorties, they have MAC stamped on them.
 
Just by looking at them some of the primaries look like they may be a problem because you need them to come straight out for a couple inches before the start turning. The primaries with the arrows are going to be the problem, these are the problem primaries with the P heads and they dont look like they have a lot of clearance. If the price is good though an hour isnt a bad drive, take a head, spark plugs, and a set of wires and see if they work. Dont go test fit them without a set of plugs and wires.

69473493.jpg
 
Well earlier i called mac and i sent him this photo, he confirmed that they are macs 79-93 t5's

He said they don't make a p header, they just fit p heads

He also said they don't stamp their headers.

thanks though
 
Well earlier i called mac and i sent him this photo, he confirmed that they are macs 79-93 t5's

He said they don't make a p header, they just fit p heads

He also said they don't stamp their headers.

thanks though

mine have a plaque welded on that says MAC and they are legit mac headers.
 
MAC makes a set of shorty headers that are p specific but that doesnt mean any MAC header fits the p heads. Most headers wont work with p heads, most headers either sit on the actual spark plug or sit on the spark plug boot not the wire, even with a 90* boot there's not much you can do.

mac longtubes fit p heads like a glove, my 86 and 7up car had them.. stock plug wires too..

these are the headers ive used on my p headed cars:

mac longtubes
bbk longtubes
summit racing shorty headers
flowtech shorties
stock shorties

thats my list and i know they work, some had some different wires but i forget which ones, usually its the 2nd and 3rd cylinder on each bank that screws you on the plugwires with the p heads..
 
Well earlier i called mac and i sent him this photo, he confirmed that they are macs 79-93 t5's

He said they don't make a p header, they just fit p heads

He also said they don't stamp their headers.

thanks though


mac used to make a p specific header but they were shorty's, and you gain alot more sound and power and TQ with lt's, frpp makes a p header as well i think its the p51 in the pn#. but the mac lt's to me fit just as well as the swap headers..

btw: mine werent stamped..
 
mac longtubes fit p heads like a glove, my 86 and 7up car had them.. stock plug wires too..

these are the headers ive used on my p headed cars:

mac longtubes
bbk longtubes
summit racing shorty headers
flowtech shorties
stock shorties

thats my list and i know they work, some had some different wires but i forget which ones, usually its the 2nd and 3rd cylinder on each bank that screws you on the plugwires with the p heads..

yeah, now i just need to figure out if i should port the heads and lower intake or leave them be. And i need to fig out if i should throw them on the way they are or do a valve job? And make a cam selection? anyone have any good experiences?
 
yeah, now i just need to figure out if i should port the heads and lower intake or leave them be. And i need to fig out if i should throw them on the way they are or do a valve job? And make a cam selection? anyone have any good experiences?


since they arent on right now, you might as well do what you can to them and then put them on, instead of doing double the work later when you want to add a cam and port em.
 
yeah springs and cam decisions are going through my head every few min. i still don't know. people say the tfs stage 1 cam is great, but i have that in the vert and i'm not really impressed with lope. i really don't know at this point, hopefully i'll talk to the guys at the machine shop and they can direct me to the right cam.

Anyone know of hand what spark plugs i run in the gt40p's?
 
i bought the mac headers and H pipe tonight for 100 bucks. i did notice a couple places where its been welded together but they are very good welds so this will definately get me buy till i can afford some new ones.

Is there anything to be concerned with a couple welds on the headers?