Rear exhaust manifold deep hollow nut on B-Block

[Resto_1]

Good Evening All,
Can someone post a picture of the deep hollownut that is used on the B-Block exhaust manifold? Have used penetrant for a couple weeks while I've been away from the project. No luck. Used my induction heater and smacked the nut with a hammer to no avail, defintely don't want to break the stud. Would like to see what I'm working with(against). Thanks

 

[QuickBpBp]

Good information here on what you could end up with.. You have a better chance to heat with a torch. Tighten it then back it off.

'69 Big Block HP Exhaust manifolds - Sleeve nuts rounded off. How can I get them out?

 

[Photon440]

Good Evening All,
Can someone post a picture of the deep hollownut that is used on the B-Block exhaust manifold? Have used penetrant for a couple weeks while I've been away from the project. No luck. Used my induction heater and smacked the nut with a hammer to no avail, defintely don't want to break the stud. Would like to see what I'm working with(against). ThanksView attachment 1985155

Here's what the nuts look like on ebay:

 

[Resto_1]

Great responses, Thanks. My concern is breaking the stud of in the head.

 

[pnora]

Great responses, Thanks. My concern is breaking the stud of in the head.

Heat it cherry red a couple times with a torch and then quench it with a hose with cold water. You could try that several times. If it breaks you might have to pull the head. No big deal.

 

[dadsbee]

This stuff is absolutely amazing. #1 Son and I couldn't budge an oxygen sensor on his GF's car last weekend, heat and all the normal **** didn't work. One good soak with this and it came out like it was brand new...

CRC Freeze-Off Super Penetrant, 326g

 

[R413]

It's a 3/8" stud, it won't break that easily. If you are heating it you will need to get it hot on the end for some time for it to travel into where the threads are.

The latest one I worked on some fool use short Allen head bolts so I needed a long Allen socket to reach down in 3" and they were very tight.