C6 used 2 different fittings over the years.
Depends on application. ie; what vehicle.

"Most" C6's had 1/8 NPT pipe to 5/16 inverted flare,
but I have seen T-Birds with 3/8 line inverted flare.
Some trucks too.

The 3/8 fittings used 1/4 straight pipe thread in the case, and either an O-ring OR a tapered seat.

"Some" 5/16 line fittings also used the 1/4 straight pipe thread in the case.

C4's I "think" all had 1/8 straight pipe and a fitting that used an O-ring at the case.

Your C6 "probably" has 1/4 straight pipe that uses an O-ring at the case.

Pics would help.

I have TFS heads and Hooker Super Comp 6130 headers for my 66 Galaxie.

I was able to get all 32 bolts in, 16 per side.
A couple of tubes needed minor massaging to get all the bolts in.

It was a little tricky, but not terrible, to get them all in.

thanks , I went brain dead, could not figure out what com stands for. dooo

Some of my old auto transmission parts manuals and repair manuals refer to those COM transmissions as CI units.
CI of course meaning Cast Iron.

Quote from: galaxiex on April 13, 2026, 08:11:16 AM

Quote from: Dumpling on April 13, 2026, 05:12:21 AM

Not clear about foundry costs, but I think this printer is around $40K upfront, but can obviously be used over and over...
.
https://all3dp.com/4/bigreps-new-one-5x-makes-big-parts-faster-easier-plus-introduces-pellet-extrusion/

That prints in PLA and PEEK which are plastics.

Not suitable for things like intake manifolds and such...

i guess that depends on the plastic used, most modern intake's are some kind of plastic these days. any threads needed are taken care of by pressed/screwed in inserts
neil.

Sure, but modern plastic intakes are usually composite and/or glass fiber reinforced nylon made in a mold.
Not sure you could print that...


I for one would not want a plastic intake on my FE...

I've found Summit sometimes makes or has, errors in some of their technical descriptions.

May not be Summit's fault... might be the tech sheet/specs from the manufacturer.
Seems like someone doesn't proofread those things sometimes...

The system cannot/must not, be completely closed.
It must be able to "breathe", or vent somehow.

If the system is sealed tight, no vent of any kind,
when it cools off, everything contracts, and creates a vacuum in the system.
That causes the hose(s) to collapse.

Transmission is E0AP

That's a 1980 or later FMX.

Dipstick tube hole in the case?

What is the casting number on the trans case?

In the red circle..

From here it looks like it starts with "E0".

If so that will be a 1980 or later FMX.


Does it have a dipstick hole in the passenger side of the case, or in the passenger side of the pan?