.

 

Do you have headers or manifolds? There are 2 plugs, on the exh side of each head which appear to cover the coolant area, I think it would be easier to check with headers, but I think it would be a good call. Let us know if that helps.

 

If you used the rubber seals front and back you may have a leak at the bottom rear corner where intake manifold mounts to block.(It is hard to see this locationat firewall,below distributor on both passenger and driver side) The rubber seals and rope seals are notorious for leaking. my 455 had same problem so I removed rubber seals and re-installed intake manifold (and turkey tray) using liberal amounts of BLACK RTV silicone. Problem solved. Good luck with build.

 

I use a thin film of ultra black RTV around the water passage areas on the gasket, and use a bead of rtv instead of the front and rear rubber seals. Clean the iron with lacquer thinner and be sure to either drop the intake right into position or have rtv on its rail as well as the block rail or it is easy to get a leak. Since my Tri Carb setup weighs 74 lb, I like to remove the oil filler tube, valve covers, and distributor for easier access. Here is a tip with the distributor: go to #1 firing, mark with magic marker the distributor housing where the rotor is at TDC (it will be about .45" CCW or past #1), and mark the housing to block with a paint stripe.

There are no freeze plugs on the ends of the heads, only the two outboard of the end exhaust ports.

 

Also, I scrape the surfaces with a single edged razor blade in a holder, and then wipe with lacquer thinner on a cloth, to get them completely clean.

 

If Joe (Run to Rund) says that's the way to do it, take it to the bank!

 

X2. That's the same way I've been doing it for decades. Are you sure the leak isn't from the coolant valve at the back of the intake?

 

Thanks for all the help.Im putting headers on next week and we think it is one of the plugs in the back of the head. I will update you when I find out.Happy holidays!!