Ford Mustang Forum banner

JBA Headers - Bad Fit

1231 Views 7 Replies 4 Participants Last post by  GTNOS
My son just got a call from the shop - installing JBA's and intake on his 05 GT. Mechanic (who is a perfectionist) said the weld on the inside of one of the headers was not allowing for a good seal, despite the gasket. He said he'd seen this before with JBA, in fact, he mentioned that his estimate might go up if he had to wrestle with the gaskets.

He is recommending pulling them off and replacing with a higher precision brand, putting the stock back on and returning JBAs (purchased from, or double gasket and live with it.

Any advice would be appreciated. Is it possible to have it re-machined? Or is it really worth the hastle? Or is this guy just being a little to precise?

Thanks for your help. Thank God for forums like this where idiots like me can learn something.
1 - 8 of 8 Posts
I am ASSuming this weld in facing the head since he wants to double gasket it. Have you actually gone down and looked at the weld. Perhaps some small amount of filing will clearence it. Since it facing the gasket I wouldn't be to concerned with the appearence.
Red, yes. He said JBA welds the pipes from the inside, leaving a bead exposed to the head. I haven't seen it, but I was thinking maybe a little machining might do the trick. Big PITA to remove, return, wait and reinstall...
Are we talking about a weld that goes all around the flange opening on each tube, or just an errant weld?

Some maunufactures put what appears to be a weld around the flange opening and is meant to be there and should have a slight machine finish to make them flat. It's done to aid in sealing and bolt torque retention and shouldn't be a detriment to installing. I have seen where sometimes the short header bolts that are included are to short, but you should be using some longer stainless bolts.

The black oxidized bolts are better but more often just plain bolts are included and that's not a good thing unless you are going to be in there all the time. You have dissimilar metals and that ain't good.

Have you contacted JBA?
I'm going by today, hope to know more then.

Sounded like it was an errant weld on one side. He didn't mention anything about the bolts, but did say the older style headers weren't working too well with the new aluminum blocks. Higher tolerances...

I'll let you know later today.

My JBA's looked perfect from the gasket side. The JBA's come with a set of gaskets aproximately 1/8" thick. The gaskets should be be more than thick enough to take care of any slight imperfection. I hope you keep them you'll love them.
Thump: Picked it back up today. Couldn't see anything, but he swore he couldn't get a good seal without cracking the weld. Maybe installer error. I'm replacing the JBA's just in case, but sticking with them. Different installer though.

FYI: They also installed an AFE Stage 2 CAI. They said the dyno readout was plus 5 hp to the ground, probably 7 or 8 at the flywheel. He also said it's running rich, needs a tuner (which he was selling).

Does any of that sound right? Should the CAI give it more hp, or is a re-tune needed.
yeah, you probably do need to retune. from what i hear, if you are doing more than just dropping in a high flow filter then you need to reflash. most CAI's claim 12 to 25 hp at the wheels but i donno which manufacturer to believe. i know the k&n is good for 12hp...seen it dynoed...:eyebulge:
1 - 8 of 8 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.