426 Hemi head bolt question

63fury500

Well-Known Member
Local time
4:08 AM
Joined
Jun 19, 2016
Messages
279
Reaction score
80
Location
Beaver Dam, Wisconsin 53916
I have a question I have been getting several different answers on and I need to get the correct answer,I have a 426 hemi with iron mopar heads,I need to know what foot pounds to torque the inside head studs with the nuts,the ones in the valley area,Ive had people tell me 30 foot pounds or I can cause cracks,Ive had peole say 70 foot pounds like the rest of the head bolts,can someone please tell me the correct torque?
 

Fran Blacker

FBBO Gold Member
FBBO Gold Member
Local time
5:08 AM
Joined
Sep 23, 2016
Messages
12,226
Reaction score
12,092
Location
Connecticut
Don't forget to put hardened washers on before nuts. From 67 SM
hemmi.JPG
 

pnora

FBBO Gold Member
FBBO Gold Member
Local time
5:08 AM
Joined
Apr 21, 2020
Messages
2,302
Reaction score
2,485
Location
Ishpeming, Mi.
Your answer is above. The only thing is what are you torquing them with. Any type of adapter that increases the length of your torque wrench requires a lesser setting.
 

Runcharger

Well-Known Member
Local time
2:08 AM
Joined
Apr 22, 2020
Messages
782
Reaction score
1,297
Location
Vernon
Decades ago I read not to go the 70 but 30 on the inner studs, that was from Ray Barton and that's what I have done ever since with no ill effects. I figured if it was good enough for Ray Barton it was good enough for me.
 

Fran Blacker

FBBO Gold Member
FBBO Gold Member
Local time
5:08 AM
Joined
Sep 23, 2016
Messages
12,226
Reaction score
12,092
Location
Connecticut
This is what you need. F ind a MAC truck you maybe buy the one you need not a set. I did that.
mac.JPG
 

63fury500

Well-Known Member
Local time
4:08 AM
Joined
Jun 19, 2016
Messages
279
Reaction score
80
Location
Beaver Dam, Wisconsin 53916
yes I was also told that 30 was the number by john arruzza and ray barton also,so why are they still posting this 70 pounds on these genaric sites?
 

70rcode

Well-Known Member
Local time
5:08 AM
Joined
Jun 28, 2017
Messages
274
Reaction score
66
Location
Usa
All Chrysler Corp sourced documentation thru the years seems to spec 75 ft lbs final "All head bolts and nuts" except the '65 A990 Race Pkg Alum head "All bolt--nuts 60 ft lbs"....I've just always used 75 on street hemi iron with no problems or leaks.....IF >30 cracks, well it was Defective anyway.....30 seems like encouraging leaks, warps & blown fire-ring sealing issues.....
 

63fury500

Well-Known Member
Local time
4:08 AM
Joined
Jun 19, 2016
Messages
279
Reaction score
80
Location
Beaver Dam, Wisconsin 53916
All Chrysler Corp sourced documentation thru the years seems to spec 75 ft lbs final "All head bolts and nuts" except the '65 A990 Race Pkg Alum head "All bolt--nuts 60 ft lbs"....I've just always used 75 on street hemi iron with no problems or leaks.....IF >30 cracks, well it was Defective anyway.....30 seems like encouraging leaks, warps & blown fire-ring sealing issues.....
Not what ray barton and larruzza say,among others,thats my problem,who to believe
 

63fury500

Well-Known Member
Local time
4:08 AM
Joined
Jun 19, 2016
Messages
279
Reaction score
80
Location
Beaver Dam, Wisconsin 53916
also its when the engine cycles that the combustion chamber sees the cracks,its uneven torque in the middle of the head,thats what the big time racers are saying???
 

pnora

FBBO Gold Member
FBBO Gold Member
Local time
5:08 AM
Joined
Apr 21, 2020
Messages
2,302
Reaction score
2,485
Location
Ishpeming, Mi.
Not what ray barton and larruzza say,among others,thats my problem,who to believe
Iron heads I would stay with the factory specs. Aluminum it might be a different story. My Iron headed hemi is at the factory setting on all of them.
 

pnora

FBBO Gold Member
FBBO Gold Member
Local time
5:08 AM
Joined
Apr 21, 2020
Messages
2,302
Reaction score
2,485
Location
Ishpeming, Mi.
Here is one other thought. The wedge blocks are just about identical bolt wise. You do not see the wedge upper row at a lower torque spec.
 

70rcode

Well-Known Member
Local time
5:08 AM
Joined
Jun 28, 2017
Messages
274
Reaction score
66
Location
Usa
My '69 came direct from factory with all 17 head fasteners tightened fairly equally.....Not experiencing any issues,.....I've continued to replicate that final 70 by doing pattern rounds of 35, 50 finishing at 75..... It's worked good for me the past 50 yrs or so..... just saying....Good luck for whatever you use,......tom
 

1 Wild R/T

FBBO Gold Member
FBBO Gold Member
Local time
2:08 AM
Joined
Jul 9, 2019
Messages
6,193
Reaction score
15,145
Location
California
3/4" head bolts? I thought 5/8"stud nuts?, been awhile. I'd go into garage but both ankles are hurtin'.

I could be wrong, I'm thinking 1/2" stud... 383/440 use 7/16 head bolts, I think Hemi's use 1/2" I sold my only Hemi in 1983 so it's been a couple days since I wrenched on one...
 

pnora

FBBO Gold Member
FBBO Gold Member
Local time
5:08 AM
Joined
Apr 21, 2020
Messages
2,302
Reaction score
2,485
Location
Ishpeming, Mi.
I could be wrong, I'm thinking 1/2" stud... 383/440 use 7/16 head bolts, I think Hemi's use 1/2" I sold my only Hemi in 1983 so it's been a couple days since I wrenched on one...
The bolt holes are 7/16-14 and the 4 upper nuts on the studs are 7/16-20. Threaded block holes are the same Hemi or Wedge 7/16-14.
 

Fran Blacker

FBBO Gold Member
FBBO Gold Member
Local time
5:08 AM
Joined
Sep 23, 2016
Messages
12,226
Reaction score
12,092
Location
Connecticut
If someone wants to buy the MAC3/8" box end what's the nut size on the studs?
 

63fury500

Well-Known Member
Local time
4:08 AM
Joined
Jun 19, 2016
Messages
279
Reaction score
80
Location
Beaver Dam, Wisconsin 53916
Here is one other thought. The wedge blocks are just about identical bolt wise. You do not see the wedge upper row at a lower torque spec.
The inner valley hemi studs are at a 3 degree angle inward so it has no comparison to what you are saying
 
Top