D Cluley
Well-Known Member
Looks like 3/8" but neither fine or coarse bolts wanted to start. May just need cleaning, but I didn't want to force anything.
What size is threaded hole in the corner of cylinder head
- Thread starter D Cluley
- Start date
When I changed the intake on my '67 Newport 383 4bbl, that SAME bolt location did not allow the bolt that came out of it to re-start and engage the threads. As if it was the wrong size, suddenly. I cleaned the bolt threads, added a thin layer of motor oil, etc, to no avail. ONLY a new bolt of the same size dropped in and tightened as it should have. As if by magic! Same size and thread pitch (normal, not "fine" or -20) as the other intake bolts. The new bolt is still in that hole.
Just my experiences,
CBODY67
Just my experiences,
CBODY67
More than likely it's a 5/16-18.
Vaanth
Active Member
The pictured threaded hole is 3/8"-16.
It looks like the threads should be chased to clean them up.
Dammit.... I had to go check...
Yep, 3/8-16.
Everyone needs to own a set of these to clean up threads. https://www.amazon.com/dp/B00DTEFSWY?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_16
Gerald Morris
Senior Member
That Bezozon link is puking when I click it. No matter for me, as I have thread chasing taps, but other folks might have this problem too w Amazon.
One of the few snap- on tools i bought new years ago. Used to be much cheaper, i think leslie makes them for them, make sure you get the full set.
Snap-on Store
Snap-on Store
D Cluley
Well-Known Member
Thanks all. The bolt went in fine after a little cleaning. That plug wire backet is supposed to attach to the end bolt on the valley cover, but that hole has always been stripped out, so it has been loose for years. Drilled the hole in the bracket a little bigger, and it is secure now on the head.
68PK21 440.6bbl
Old Man with a Hat
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