Experts - Need your thoughts on this girl I’ve had for 35 yrs (1980 V-6, 229, daily driver)
Quick History:
- Water pump & fan clutch ~ 4 months old; new 180 degree T-Stat
- TWO temp sensors (top of intake stays @ 180-190; pass side of engine between cyl 1 & 3 starts @ 190, then once hot will float-up to about 220-240 for a while then slowly return to 190-200, then back & forth. I suspected air being pulled into combustion chamber via bad head gasket.
- Never any oil in radiator fluid or visa-versa
- Some (minor) smoke at start-up (suspected valve seals); small amount of moisture in tail pipe
- No significant coolant loss
- Used an AutoZone block tester and saw no indication of exhaust gasses in coolant

3 Weeks ago after work (the dam busted):
- Significant water leakage out of tail pipe
- Steam/water loss out of passenger side of engine; suspected head gasket finally gave out
- In a pinch, opted to try “Steel Seal Elite” based out of CA; seemed to work. No steam or water loss from tail pile; seemed to have better gas pedal response/power.

Today:
- Still no indication of steam or water loss from engine pass side
- No indications of water from tail pipe
- No coolant loss or oil in coolant
- No coolant in oil; looks perfect
- However, my pass engine side (between cyl 1 & 3) temp gauge still spikes-up to about 220-240 after running hard for about 10 minutes. It can eventually come back to about 200, but can fluctuate back & forth while driving.

Thoughts/Suggestions:
- Am I on borrowed time with the head gasket?
- Is there any reason to suspect anything else (i.e. intake manifold gasket)?
- With 270K miles on everything, would you even bother replacing the head gasket or simply pull the motor (and TH-200 trans) to go fresh with standard 350 & 350 trans?
- Anything else I should consider?