Headman Headers

[50 Coupe]

I got a set of Headman block huggers for my 68 383 going into my Coupe. The motor is an hour away from where I live and want to know what size bolts I will need for the exhaust manifold studs? The motor didn't come with any.

What nuts size fits?

Also, can I use the studs or will I need to remove them and use bolts for the headers?
Thanks.

 

[themechanic]

I got a set of Headman block huggers for my 68 383 going into my Coupe. The motor is an hour away from where I live and want to know what size bolts I will need for the exhaust manifold studs? The motor didn't come with any.

What nuts size fits?

Also, can I use the studs or will I need to remove them and use bolts for the headers?
Thanks.

I think they're a standard size. Just search header studs/bolts. Or call your local auto parts store.

 

[themechanic]

3/8" - 16



https://www.summitracing.com/search...ize/6-3l-383/engine-family/mopar-big-block-rb

 

[50 Coupe]

3/8" - 16



https://www.summitracing.com/search...ize/6-3l-383/engine-family/mopar-big-block-rb

OK, I got the bolts that came with the headers but was going to try to avoid pulling the studs from the heads and just get some bolts. It is the size of the bolts I am looking for. So far, looks like they may be 3/8 course or fine.

 

[66chargerpat]

I think the oem studs are two sided. Course in the head, fine on the outside. I can check when I get home. IICR

 

[themechanic]

OK, I got the bolts that came with the headers but was going to try to avoid pulling the studs from the heads and just get some bolts. It is the size of the bolts I am looking for. So far, looks like they may be 3/8 course or fine.

The threads in the block are 3/8" - 16, according to the products in the link.

Uncle Tony's Garage (UTG) just did a video on removing exhaust studs from the block.

 

[50 Coupe]

I think the oem studs are two sided. Course in the head, fine on the outside. I can check when I get home. IICR

Cool, Thanks!!

 

[33 IMP]

Threads in the heads for the ex manifolds are 3/8-16 coarse, and wet. You will need a sealer on the bolts or studs.
You can use the studs and nuts if you can get the header on with them. With shorty block huggers they may work. Long tube headers almost always require header bolts with a reduced size head (either a 7/16 or 3/8 hex or twelve point, instead of the normal 9/16 hex on a 3/8 bolt)
Edit: customized wrenches are sometimes required too.

 

[Lefty71]

use bolts for the headers?

3/8-16 as others have said. Get yourself a tap or thread chaser and clean those head threads before starting, cuz there's gonna be goop residue from whatever sealer the last guy chose to use. Length wise figure 3/4" penetration into the head, and add for your gasket and header flange thickness. Don't go too long!! I love old school soft set Permatex on the threads, then let it set a good day or so before filling the radiator and starting up the motor. HTH, Lefty71

 

[silversedan]

if possible use as many factory studs as possible. test fit headers against head and see what clears.