Could 69 or 70  351w manifolds work?

Or modify some cheap tri-y’s?

Last edited by Nos681 (2/18/2021 10:24 PM)

Foxbody headers will not fit in a 65.

If anyone knows of a 65 specific header that will fit the GT40-P heads, let me know. 

I am trying to avoid having to mske a custom h-pipe. I figure if I get stock manifolds I will be able to buy off-the-shelf exhaust system.  We are so far away from town it will be a real pain to get the car to a muffler shop.  If we keep it stock we can just bolt parts on and go.

Steve, this is from a post by Huskinhano back in 2019:

I'm using MAC longtubes. They actually fit pretty well. On the driver's side #5 tube slips in after the main header body goes in. It makes it installation much easier! No need for a PS ram drop bracket typically needed. They also have great ground clearance and use the ball & socket collectors. Even though they weren't designed for GT40P heads, they'll fit, that's why I'm using them.

No issues with the starter or Z bar linkage.Last edited by Huskinhano (11/05/2019 7:04 PM)

Last edited by TimC (2/19/2021 1:03 PM)

MS wrote:

Thanks, Tim!

My goal is to keep it as stock as possible. I have a good set of 351w heads we could use, but that means I have to figure out and order a set of custom pushrods. It’s always something...

Well.... I also looked over on another Mustang site where Tom provided more info on his GT40P install. 
He says"
Early 70's 302 Mustang manifold will work no problems with the plug angle. The only issue with them is they will not work with power steering cars as the outlet dumps right were the PS ram is."

I also did a quick  internet search for Mac headers for 1965 Mustang.... no joy....
 

Unless he's running a C4 or smaller you will need a custom H pipe anyway.  Certainly for an AOD.  Don't know about the T5.
As I recall we just removed enough iron wherever it was necessary to get a plug socket in there.  It's pretty obvious once you bolt up the mannys.
 

I run the Hi-Po manifolds on my GT-40P heads with no modifications or grinding. Fit great, don't leak and mounted a stock H pipe behind it to start my exhaust system. Been running them for 15 years no issues.

Are you the same 'Barry' that was a member on here YEARS ago?!
6sally6

I just got Windows 10 and wanted to try and post a picture from my computer, which I have not been able to do using Windows 7.  IT WORKED!!!  Since I lost EVERY SINGLE PICTURE I EVER HAD when the computer hard drive crashed, this was the only pic I could come up with, found on an old thumb drive.

Took my computer to an expert in such matters. Nothing could be retrieved from the hard drive.

Bullet Bob wrote:

Idaho Barry wrote:

I run the Hi-Po manifolds on my GT-40P heads with no modifications or grinding. Fit great, don't leak and mounted a stock H pipe behind it to start my exhaust system. Been running them for 15 years no issues.

Welcome to the best place on the Web.  What part of I-dee-ho are you from.  My Dad's family were in the area around Makay...grand mother lived in Arco.  I did my first six years in that country.

Are you sure those are GT-40P heads and not the earlier GT-40's?

BB1

Yes sir I am positive these are the 40P heads. I run them with the Hi-Po manifolds and Steve's cable clutch setup for my T-5. You've seen this car Bob. We met in Kalispell Montana for Steve's bash years ago. Dark green 65 convertible. I used to go by Barry then on this forum. I haven't been on here for some time now getting involved with other projects and builds, but came back and could not remember my password, so I created a new user name. I will post later on another subject. I'm trying to figure out this fuel injection stuff and need help.

Idaho Barry wrote:

Bullet Bob wrote:

Idaho Barry wrote:

I run the Hi-Po manifolds on my GT-40P heads with no modifications or grinding. Fit great, don't leak and mounted a stock H pipe behind it to start my exhaust system. Been running them for 15 years no issues.

Welcome to the best place on the Web.  What part of I-dee-ho are you from.  My Dad's family were in the area around Makay...grand mother lived in Arco.  I did my first six years in that country.

Are you sure those are GT-40P heads and not the earlier GT-40's?

BB1

Yes sir I am positive these are the 40P heads. I run them with the Hi-Po manifolds and Steve's cable clutch setup for my T-5. You've seen this car Bob. We met in Kalispell Montana for Steve's bash years ago. Dark green 65 convertible. I used to go by Barry then on this forum. I haven't been on here for some time now getting involved with other projects and builds, but came back and could not remember my password, so I created a new user name. I will post later on another subject. I'm trying to figure out this fuel injection stuff and need help.

Well...good to see you back, Barry.  As for the 40P's I prolly have my head where the sun don't shine.  Josh said the only grinding he recalls seeing on those HIPO mannys....he bought 'em from my Falcon bud...is on the  sides to clear the towers.  That's why we didn't use them on the Falcon project, they would not clear the towers. 

As for your EFI project, I'm betting someone on here will have some kind of answer.
 

Barry, yep I'm also runnning HiPo's and they do clear the Mustang towers just fine.  The application that gave us trouble was a 64 Falcon.  I discovered that the Falcon compartment is a tad narrower and a bit longer than the Mustang and a lot deeper.