GT40P headers for a 71?

[beastmanh]

First of all, hello to all, and I'm very glad I found this forum I am building my mustang from when I was a kid (finally) and I know this site is going to be a huge help.

Now, I DID search the site for possible answers to this, and also searched the internet for quite a while with no concrete results. I recently heard that the JBA shorty headers will work in a 71 with GT40P heads, but those are the ONLY ones I have heard will work. Are there any CONFIRMED headers that have been used in this situation? For that matter, are the JBA headers confirmed either? I'd like to buy cheapo headers, long tubes preferably, but if the JBAs are the only ones that will fit I guess I'll order them asap... The headers are the only thing stopping my car from being back on the road, so I'm in a bit of a hurry to figure out this problem... I'll prolly one night them

Anyways, thanks in advance to anyone who might have some insight into this LAME problem... (I wish I had gotten GT40s, but too late now)

 

[Mikes73]

I've had good luck using BBK unequal length shorty headers with gt40p heads, clearance was good with these headers.

 

[beastmanh]

I just finished sending these back. For a 71 with a C4, the collectors will not clear the bell housing. Not even close. Would have to notch out your block/bellhousing and notch the collector on the bbks. UPS literally picked them up yesterday, no dice. The plug clearance was fine, but no WAY they will actually install in a 71-73 mustang. What model car did you have that the BBKs worked on?

 

[Mikes73]

Sounds like you are going to have to get a set custom made.

 

[beastmanh]

Well I'm looking for "cheap", and from my experience CUSTOM != CHEAP, if you know what I mean So I have decided I'm going to order the JBA shorties tomorrow, they are stainless and look alright, so I guess they are worth the extra $$. I will update this thread when I get them (later this week hopefully) and at least let interweb searchers know if they are a confirmed fit or not. This is the ONLY holdup right now keeping my car off the road. Crossing my fingers!!

 

[beastmanh]

Ok, just for the reference of other GT40P heads owners in a 71-73 mustang, the JBA 1650S-2 1-5/8" Shorties WILL fit and clear everything. The only pain is getting the rear driver side bolt in. Other than that, everything is easy access. The BBK unequal length shorties WILL NOT WORK in a 71-73 mustang with GT40P heads. The tubes on the BBKs don't clear the steering box, and the flange gets hung up big time against the side of the block and bell housing. I just hope a few people see this post before ordering the bbks based on untested information like I did :/

 

[droptop73]

That's great information! Thanks for posting. I'm planning a 5.0 swap but will be using the conventional style heads.

 

[beastmanh]

Not a problem Droptop73 Just as a side note, the GT40 heads (without the "P") are supposed to make more power than traditional heads, but they keep the same spark plug angle as original heads, so you don't run into header issues at all. I've heard they make as much as 20 more hp. If I were to build one again, I wouldn't mess with the GT40P heads, but I got them fully rebuilt for $200, so I couldn't pass it up.

 

[droptop73]

I just picked up a 60k 5.0 Exploder motor for $400.00. I'm just planning on cleaning it up, checking leakdown, bearings and swapping the pan and oil pump before dropping it in and getting it going. I may swap the cam if I can get the right deal.

Are you planning on running catylitic converters? I am thinking about it to eliminate the gassy exhaust smell.

 

[Mikes73]

Ok, just for the reference of other GT40P heads owners in a 71-73 mustang, the JBA 1650S-2 1-5/8" Shorties WILL fit and clear everything. The only pain is getting the rear driver side bolt in. Other than that, everything is easy access. The BBK unequal length shorties WILL NOT WORK in a 71-73 mustang with GT40P heads. The tubes on the BBKs don't clear the steering box, and the flange gets hung up big time against the side of the block and bell housing. I just hope a few people see this post before ordering the bbks based on untested information like I did :/

Sorry I caused you so many problems, I will never make that mistake again. Maybe my unequal shorty BBK headers were really reboxed JBAs.