[steve25]

Did you mistakenly get head bolt set N521AF ( for round port heads ) or maybe yours are packaged wrong?
The round port heads take longer bolts in many locations.
The longest bolt for D port heads should be 4”.

[70 Bonneville]

Originally Posted by steve25

Did you mistakenly get head bolt set N521AF ( for round port heads ) or maybe yours are packaged wrong?
The round port heads take longer bolts in many locations.
The longest bolt for D port heads should be 4”.

This weekend I pull the head off and planning these:
Compare bolts one by one to the factory ones. Head is also factory.
Make sure the holes are clean.
Measure deck and head for flatness... did already but doesnt hurt
Order gaskets. So far I used only FEL-PRO 8518PT do you think i should try another brand?

Beforehand all above, compression and leak-down test just to see where we are.

Am i missing something?

[Schurkey]

Originally Posted by 70 Bonneville

Order gaskets. So far I used only FEL-PRO 8518PT do you think i should try another brand?

Sam Agnew had a major issue with Fel-Pro 1018 gaskets, there's an oblong hole in them that was allowing an oil path on his home-ported Edelbrock heads. He replaced the oblong-hole Fel-Pros with Mahle gaskets that have a smaller, round hole.

https://forums.maxperformanceinc.com...=866228&page=3
starting about Post 116, and onward.