Aftermarket heads/power steering stud

Mustang5L5

i'm familiar with penetration
Mod Dude
Feb 18, 2001
34,044
10,308
224
Massachusetts
this is the thermactor hole

D387C94A-E8C3-4745-8180-11A20152B5A7.jpeg


This is how the AC brackets mount

483F835D-E0A8-469F-A865-DEA374973A25.jpeg
78C5B719-9638-455A-800A-0970EE5BCF89.jpeg
 
  • Sponsors(?)


Mustang5L5

i'm familiar with penetration
Mod Dude
Feb 18, 2001
34,044
10,308
224
Massachusetts
Not that I’m aware of, only because every single head I’ve worked with has had this hole present, smog compliant or not, so I’ve never had to improvise. All 302s use the 3 hole accessory mounting. It’s fairly standard and I’d be surprised to find a modern head without it. I know that’s not the answer you are looking for, but not having that hole would not be a typical configuration that most of us have dealt with.

honestly, I would contact blueprint about this. I would not be drilling holes into my $1k+ heads in my garage.
 

Mustang5L5

i'm familiar with penetration
Mod Dude
Feb 18, 2001
34,044
10,308
224
Massachusetts
I’m still lost. This is the pic you posted on FB. This would be the equivalent of the thermactor hole if the heads were smog conpliant. The stud goes here. You don’t have this hole at all?

D89BDE22-B222-4374-8C27-7AEE89F9D76C.jpeg
 

OldManRiver

Active Member
Feb 14, 2015
130
78
38
46
Central Wisconsin
So what your saying is that the hole nearest the exhaust port(what would be the thermactor hole) in your head is not in the same position shown here on this pic of a Blue Print HP9008 series head? ^ beat me to it.lol
HP9008_-_B_1903x.jpg
 
  • Like
Reactions: Mustang5L5

Boostedpimp

15 Year Member
May 8, 2003
1,062
361
124
NJ
The answer is simple... drill/tap and be done with it. If your not confident enough then mark it and take it to a machine shop to have done.
 

HemiRick

Active Member
Jun 28, 2020
291
80
38
57
Memphis TN
So what your saying is that the hole nearest the exhaust port(what would be the thermactor hole) in your head is not in the same position shown here on this pic of a Blue Print HP9008 series head? ^ beat me to it.lol
HP9008_-_B_1903x.jpg
no my holes are the same as this pic, whats missing is the thermactor hole below the top right hole. There should be 4 holes in the heads not 3.
 

Mustang5L5

i'm familiar with penetration
Mod Dude
Feb 18, 2001
34,044
10,308
224
Massachusetts
This hole?
DCE74468-55E1-4544-91AB-D540C4EDB27C.jpeg


the only thing that hole is used for is bolting on the smog tube at the back of the engine. It has no use up front.
8AC42E03-C7E2-4664-A4F6-8BC7828AC484.jpeg
 

HemiRick

Active Member
Jun 28, 2020
291
80
38
57
Memphis TN
I dont have the heads in my possesion ATM as they had to go back to machine shop....maybe the ends of one of the heads is drilled differently than the one I was trying.
 

Mustang5L5

i'm familiar with penetration
Mod Dude
Feb 18, 2001
34,044
10,308
224
Massachusetts
The one with the bolt in it is clearly seen on the generic photo of the heads you have. You should be able to mount the stud in there no problem.

if that’s missing, it’s a issue you need to take up with blueprint as their photo shows the threaded hole in the correct place. Based on that generic head pic, there is nothing that would prevent you from using the AC and non-AC accessory bracketry.

I would not drill/tap. Sounds like a QC issue with blueprint that you need to take up with them.

Either that or you lined up the wrong hole when test fitting the brackets. With the Ac bracketry, you are only using 2 holes.
 
Last edited:

Chuckman

GTFO you fat, heavy bastard
15 Year Member
Oct 21, 2005
1,588
967
173
st. louis, mo
That 3 hole pattern has been probably used since the 60s, the thermactor just drilled thru an existing hole in the pattern. As others have said if that hole (two in the pattern are 7/16-14 with one 3/8-16 in a non smog head, smog head I think all are 7/16 and the thermactor on the the front side gets a screw in reducer to 3/8 to block the thermactor) is missing, it is a machining issue and needs to go back.
 

7991LXnSHO

Now I want a 10 year badge
10 Year Member
Sep 1, 2010
3,320
683
174
Kearney, NE
That 3 hole pattern has been probably used since the 60s, the thermactor just drilled thru an existing hole in the pattern. As others have said if that hole (two in the pattern are 7/16-14 with one 3/8-16 in a non smog head, smog head I think all are 7/16 and the thermactor on the the front side gets a screw in reducer to 3/8 to block the thermactor) is missing, it is a machining issue and needs to go back.
If Rick has already put the time and money into these heads to prep them, he has plenty of reason to be upset. Just not at us.
@HemiRick do you need someone in Kearney to stop at Blueprint Engines and make something happen? I am still mad from back when they were going by Marshall and sold me a long block that smoked from poorly knurled valve guides, then would not warranty it.