1970-W30

In the process of tinkering with my barely functioning AC unit, I discovered I have a bad head gasket in my newly rebuilt .030 over 403. I had noticed it didn't have as much power lately and the idle wasn't quite as smooth as it should be, but I chalked it up to the very high temps we've had here lately. 110 degrees plus most of the time. Haven't done a compression test yet, but I see a constant stream of air bubbles coming up in the radiator overflow container when the engine is running and even after it's shut down for a bit.
Strange thing is the oil is still clean and bright as can be and I don't notice anything out of either tailpipe, but it is loosing coolant.
I used the 1/2" ARP headbolts with their lube when assembling the engine with #5 heads and the Fel-Pro 8507 PT head gaskets. The one thing that bothered me when torquing down the headbolts was the way lower specification (100 lb.ft.) ARP listed using their lube. If i recall 130, with bolts dipped in oil, is what factory specs are. The heads were milled .010 to true them up. My question, should I re-use the ARP bolts with new ARP lube and crank them down maybe to 120 lb.ft. to prevent another head gasket failure??

cutlassefi

Tightening the bolts down past their recommended torque settings is a recipe for disaster.
If you're still having problems with everything torqued correctly then you have other issues.

Grace Stinespring-Welch

it could be your intake gasket also.

svnt442

I had an odd one when I put my 455 together 20 years ago (ouch...that hurts just thinking about it). After I had about 5,000 or so miles on it I started getting coolant spraying out passed the radiator cap under hard acceleration, but never any other time. I didn't get it because like you, no coolant in the oil and nothing out the tail pipe.
Then one day after work (when I was giving my boss a ride home of all things) I decided to mess with a TT 300 ZX and POOF......Spy hunter was born! I was tossing coolant out of the right pipe like it was nobodies business.
I figured out at that moment why I was tossing coolant whenever I floored it. the head gasket was bad, but not blown. There wasn't enough pressure in the cooling system to blow passed the bad spot, but when I floored it the cylinder pressure built up enough to blow into the cooling system and thus toss the coolant all over my engine compartment.

Now the fact that you are getting bubbles constantly points more to a weak cap to me. I would start there by replacing it with a 16lb cap and see if it stops. You never know.
A cheap and easy fix is always better that a difficult expensive one (that might not be the issue).

nsnarsk65cutlass

Maybe not a head gasket but a crack somewhere?

1970-W30

Well, I have a definite answer, ran a compression check this morning, warm engine with the throttle open. checked 1 thru 7 then went to the passenger side and did 2 thru 8. All tested at 150-155 except for the last one to be tested, number 8, it pegged at 20 psi. So there is the answer to whats wrong. Cylinder 8 is basically dead. Question, should I reuse the expensive ARP bolts with new lube or spring for a new set? Also should I retorque the head bolts after a warm/cold cycle even though FelPro doesn't require it? I didn't retorque after the initial assembly. Both head and block will be checked with a straight edge, I just want to make sure this doesn't happen again. The engine did hit 230 degrees a few times, but I doubt that would be enough to have a head gasket fail........

TripDeuces

You'll be fine reusing the ARP bolts. Many people swear by cycling the ARP bolts/studs several times. Personally I've cycled mine half a dozen times with no problems. ARP lists the torque for 1/2 fasteners from 110-145 lb/ft depending on which you have. I would have no problem torquing them to 110 lb/ft all day long. Just lube the threads and under the bolt head.

rr480

My advice is pull the head get it checked for cracks, ask the machine shop about the head bolts if head is good reinstall with new gasket and torque to factory specs. I hope there was not any coolant leaked into the cylinder, it could damage the rings on that
cylinder.

1970-W30

Just got the head off and I see where the problem is, right from the cylinder to the water jacket is a rust stain. That's where the gasses blew right into the cooling system. My 65 year old bones ran out of steam, so tomorrow I'll check the block deck and see if it's going need a resurface, I hope not....The head gasket, as far as I can see, doesn't show any damage, not good.... Couple of tips, I'm glad I used anti-seize on the exhaust manifold bolts, they came loose real easily, the other thing is always unhook the ground strap from the head before you try lift the head off the block, it will save a lot of strain on the back, don't ask why I know this.....

Octania

Looks like an easy fix- well, relatively easy
Be sure to check the head closely [with a magnifying glass or better] in that area.

ARP at 130 ft-lbs or
factory issue bolts at 130 ft-lbs would be what I would do.
Tighten in three stages, then go over the pattern again.

cutlassefi

Torque them to the recommended spec with the recommended lube. Don't over tighten them.