426 Hemi head bolt question

[63fury500]

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]

Don't forget to put hardened washers on before nuts. From 67 SM

 

[pnora]

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]

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]

This is what you need. F ind a MAC truck you maybe buy the one you need not a set. I did that.

 

[63fury500]

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?

 

[1 Wild R/T]

This is what you need. F ind a MAC truck you maybe buy the one you need not a set. I did that.View attachment 1287412

https://www.ebay.com/itm/284811923638?hash=item42501d10b6:g:sj4AAOSwVWVifS~K

 

[70rcode]

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]

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]

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]

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]

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.

 

[Fran Blacker]

https://www.ebay.com/itm/284811923638?hash=item42501d10b6:g:sj4AAOSwVWVifS~K

3/4" head bolts? I thought 5/8"stud nuts?, been awhile. I'd go into garage but both ankles are hurtin'.

 

[70rcode]

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]

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]

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]

If someone wants to buy the MAC3/8" box end what's the nut size on the studs?

 

[1 Wild R/T]

If someone wants to buy the MAC3/8" box end what's the nut size on the studs?

It they are standard hex, not an over-size being 7/16-14 they should be 11/16

 

[63fury500]

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

 

[63fury500]

It they are standard hex, not an over-size being 7/16-14 they should be 11/16

9/16