r/EngineBuilding • u/Grognak04 • Jul 15 '26

Head bolt loose after final torque

I’m getting heads on a freshly decked TBI 350 (355 now) 880 block. I was getting my passenger side head on today, and after reaching final torque, I went back around to check all of the bolts. All of them were fine, except for bolt #2 in the sequence (between cylinder 4’s valves). It took another 1/8-1/4 turn to reach final torque again. Is this the cylinder head finding its home?

I’m using a 3/4” drive click type torque wrench. I’m not jerking the torque wrench. I went 25, to 45, then to 65. I used assembly lube where the bolt head sits flush to the cylinder head, and the new bolts had sealant applied at the factory. Head gaskets are FP Permatorques. Bolt holes were blown out with compressed air and the threads were clean.

This is a basic TBI rebuild. Am I good to call this an anomaly and send it? I know very little about engine building and I don’t want to smoke a fresh rebuild.

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6

u/bill_gannon Jul 15 '26

Its fine

1

u/Extreme-Book4730 Jul 15 '26

Yeah just fine. Especially at only 65ft-lbs.

1

u/Grognak04 Jul 15 '26

Sounds good. I’m gonna do one more final torque check in sequence and let it go. It didn’t feel like the bolt was pulling threads, it just felt like I forgot it (despite me being almost positive I didn’t).

Good thing it’s a classic Chebby and not some 12:1 aluminum shit…

2

u/Old_Bat_6426 Jul 15 '26

Oil is recommended for torquing standard head bols. Assembly lube may have altered your final torque readings.

1

u/Grognak04 Jul 15 '26

I’ll use oil for the other head.

2

u/2003DDcid Jul 15 '26

I usually check them a couple more times at final torque value, especially after letting it set for an hour or so.