273 exhaust manifold gasket

[seabee]

Hi All,

I have some coolant getting in the exhaust and down the side of the block from the forward manifold bolts. From what I gather, these bolts go through a coolant passage and have to be properly sealed or they leak. What gaskets and sealant is the best fix for this? I've seen talk about the "Aussie" Gaskets but don't know exactly where to find them. Thanks in advance

Seabee

 

[RedFish]

I can't imagine how coolant would enter the exhaust due to those studs leaking. They will leak to the outside of the block.
The original exhaust manifold gaskets for a 273 was also a sheet metal shield protecting the plug wires.
With todays heat resistant wires you really dont need those knickle slicing shields and I dont believe thay are reproduced any way. Common 318 gaskets will work.
Removing those studs ( 2 forward most and 2 rear most in water jackets ) can be tricky. They break before backing out very offen. If you can get them out the next step is to get the studs and the holes clean and dry so a hi-temp silicone ( Permatex ) sealant will bond and stop the leak. Good luck

 

[4spdragtop]

Dad and I are going to put his exhaust studs in and I knew there was something about certain studs potentially leaking coolant. I have Permatex thread sealant with teflon(looks like white thick glue), should or can we just put it on all of the studs??

Hey Ben, dad has the orig shields for his 273, were they the gasket, or were they simply shields??

 

[RedFish]

4 corner studs go into the water jackets and do need a sealant. The others are bolts in dry holes but to put a little antiseize in those threads cant hurt.

The gasket and heat shield is one part. The gasket portion of it is stamped steel just like the OEM intake gaskets. The heat shield portions are riveted to it.