Head Gasket on 429 - If it were put on upside down, what would happen?

My newly rebuilt engine got hot immediately on first run. Did this 3 out of 3 tries, blew hose off first two times. It fails compression test badly.

My question it this... Can the head gasket go on upside down? If so, what would the result be?

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The rings have not seated on a new rebuilt engine so compression  results could be in question until they do 

No record here of anyone putting a head gasket on backwards so have no answer to your  question or the results of doing that 

Which hose is blowing off ?

If you replaced your water pump —some new  pumps have come out of the box with the impeller in the wrong location causing engines to overheat 

If you believe the head gasket was put on upside down pull the heads and replace the  head gaskets is all you can do 

Be sure your rocker arms are replaced correctly as many professional shops have put them on the wrong way 

Who rebuilt the engine ?

Best I can do 


lower hose on pump was first. Upper hose from radiator was second. I thought I hadn't tightened them sufficiently. When I ran it today I made sure there were no air pockets, and the radiator tanks got hot right away, and this thing was stone cold since Wed night when i started it. Three cylinders under 100. The other five ranged 117 to 170. I'd just about bet the ranch it's head gaskets. I'll know fairly soon. Local guy rebuilt it. It was smooth as glass when it was running. It has 14 1/2 minutes of run in time on it at over 2000 RPM the whole time. I've done this sever times with my Camaro and this never happened. Even checking the shop manual, I didn't do anything wrong.

How will you know soon ?

I'm going to pull the heads off.

Usually the engine block will get to 180 degrees and the thermostat will open and then the rad would get hot to the touch then 

Not sure why the rad got hot so quickly on you 


Check you oil to see if it is milky ( coolant mixing with oil ) 

Result of bad head to block gasket seal 


It isn't. The oil looks fine, and the level did not rise. When I pulled the valve covers off, there was no trace of water visible.

The compression is a bit worrying. Was it a complete rebuild, or just heads and gaskets? You can always do a pressure test of each cylinder (cylinder leak down test) to get an idea.

Regarding the temp, have you tried turning the engine without the thermostat to see how the coolant flows and also removing air bubbles? I would take an old thermostat and remove the thermostat part and only use the outer ring fitted in the gasket to get a proper seal with free flow of coolant. You could try this test with spark-plugs out and let the starter just run the engine a few minutes to get an idea if the water pump is functioning properly. If you really want to observe the coolant flow use an open bucket, 1-2 feet above the engine, and connect the cooling system to it (suction from bottom of bucket and return over the top). If done properly you could, with another bucket and a stop watch, calculate actual flow of coolant.

It was a complete rebuild, top to bottom. It got an overbore by .020 and new pistons, rings etc. Standard size bearings. Rebuilt rocker shafts. All the usual items. I'm looking forward to getting the heads off.

Regarding the high temperature, did you go back with an original temp sending unit, or known good one? The new aftermarket ones are crap and are miscalibrated and will show HOT on the instrument panel temp gauge. I always use an IR temp gun and point to head right next to the temp sending unit. These are 20 bucks or so and will give you an exact reading and is good insurance.

It takes some time for the rings to wear in but having done that your compression seems way off. I would guess compression rings not installed correctly or perhaps incorrect. It is the oil ring that I found finicky and second guessing when I rebuilt mine. The compression rings seemd pretty straight forward. There is a top and bottom side to them.. not sure what would happen if you install upside down. On the head gaskets I don't recall top side or bottom side but you need to use your eyeballs and grey matter upstairs to ensure the holes all align in gasket to engine. It would be pretty careless of your rebuilder not to do that. and of course torque things down correctly.

Let us know what you find out ... and make sure you have a good temp sending unit and/or temp gun. 

Original sender. Glad you mentioned the temp gun. I'm going to pick one up. Looking at photos, the gasket appears to be symmetrical from side to side, except for one hole. From the location of that hole, I suspect that it is the oil supply hole to the rocker shafts. The hole in the block is directly in line with the main oil gallery at the rear of the block. The rocker shafts are getting oil, so the gaskets were in right. The shop manual does specify that the top of the gasket says TOP, and that they must go in that way. I really suspect it had an air pocket, I missed it, and that ultimately caused pressure in the water jackets that took out the gaskets. I'm anxious to find out if I'm right.

How about a stuck thermostat or air bubble?  Maybe remove t-stat and test.



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