408w Engine Build Questions

[ChromdOutDubs]

Ok well the bottem end of my motor has been assembled for some time now, but nothing is torqued down yet. I will be buying my cam/lifters/rockers/pushrods soon, so i wanted to get the bottem end out of the way. I was just wondering what are the torque specs for the maincaps on a '74 351w. I have seen 2 or 3 differents specs so far, it has studs instead of bolts so i can put my main girdle on, not sure if that would change anything. I aslo would like to know the rods specs too. Thanks guys.

The Torque Specs i found so far is....

Main Bearing Caps: 60-70 ft-lbs
Connecting Rods: 40-45 ft-lbs

-AJ

 

[86bluecobra]

70 ft/lbs for mains is the 302 spec for a 351w you want to go to 105 ft/lbs.
rods are torqued to the specs you stated.
I had a book when i assembled my 351w. the 70ft/lbs was the torque for the mains for non performance applications and 105 for the performance application.

 

[ChromdOutDubs]

Any idea what book it was, im lookin at mine here, and its mostly 302 stuff.... Its called "How to rebuild the Small-Block Ford" gives me the basic but not much info for the 351w. When i start to torque stuff down, i know i should try to turn the assembly to make sure all is good... But how hard should it be to turn? Thanks

-AJ

 

[bluevenom867]

Dont turn anything till its torqued! If you dont put proper torque on the cap,it wont properly crush the bearing (under no torque,the bearings are actualy a little oblong) and it will turn hard or not at all.

Once everything is toghter,shot block should be able to be easly turned with a socket wrench. Use plastigauge and check clearances.

 

[ChromdOutDubs]

Any kind of torque pattern i should use when doing the main caps? Thanks

I have already checked clearances and plastigauged the mains, it all checked out, just need to torque everything down.

-AJ

 

[bluevenom867]

Start in the center and work out wards.

Go in seqench, 35,55,75,105 is what I usually do,then break it loose (90*),then repeat a few times.You can also slid the crank back and forth a little to help aling the caps after you break them loose first time.

 

[ChromdOutDubs]

then break it loose (90*),then repeat a few times.You can also slid the crank back and forth a little to help aling the caps after you break them loose first time.

Im not understanding you are talking about on this step???? Tighten them all down, then loosen them back up and re-torque... This whole step you said has be confused.

AJ

 

[bluevenom867]

Im not understanding you are talking about on this step???? Tighten them all down, then loosen them back up and re-torque... This whole step you said has be confused.

AJ

Yes.

1.Torque them like this,from center cap outwards. 35,55,75,105ft-lbs

2. The put a breaker bar on them,and loosen them 90 degrees. Move crank for and aft to help aling caps. Reapet 1. two times

3.Break them all loose 90 degrees again,hand thigthen them,then torque them same pattern right to fianl torque (105ft-lbs,or differant if your using ARP,ect.) and hold for about 3 seconds.

4. Make sure crank rotates fine,check the end play and if its in spec,your good to go.