Head Bolts won't line up

rogeroadster

rogeroadster

Senior Member
I'm installing a cast iron Cragar head on a B block and I'm using bolts rather than studs due to firewall clearance. If I install the bolts beginning from the rear and working forward with just enough threads to get them started, the left front hole in the block will not line up enough to get the bolt started. If I work from front to rear, the left and center rear bolts will not line up. The block does not appear to have been machined in any way that would move the location of any of the bolt holes. I've tried grinding a taper on the bolt to get it to start but it doesn't help. Anybody got any good ideas? I may have to go to studs but would like to hear from someone who might have had this problem before.
Studs are undesirable because this engine is installed in a model T and the engine setback into the firewall keeps me from lifting the head over the studs. If I should ever need to change a head gasket I would have to pull the motor to get the head off.
 
Will a stock flat head fit? If it does you likely have a problem with the hole placement in the Cragar.
 
Hi how much is it out, if not much like ten thou or so you could diy grind the hole a bit on that side, it can't be out by much. Some other guys will chime in with maybe better ideas
 
Are not studs thinner in the shank than threaded potion ? Maybe you can turn the unthreaded area down to give more clearance , Bore head hole out or just send it to me Ill pay the freight .
 
Flathead said:
Will a stock flat head fit? If it does you likely have a problem with the hole placement in the Cragar.
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Some good ideas already, thanks. I took a stock head off this newly rebuilt motor, changed the cam and now I'm trying to install the freshly rebuilt Cragar on this block. The previous owner of the head says he ran it for 20K miles using bolts on a B block.
 
The bolt holes in the head could have been thrown out of alignment if the head had been warped and then re-surface flat again. Maybe reaming out the holes a few thou. with an adjustable reamer would solve your problem.
 
RUNNERBUN said:
The bolt holes in the head could have been thrown out of alignment if the head had been warped and then re-surface flat again. Maybe reaming out the holes a few thou. with an adjustable reamer would solve your problem.
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Thanks, another good thought.
 
rogeroadster said:
I'm installing a cast iron Cragar head on a B block and I'm using bolts rather than studs due to firewall clearance. If I install the bolts beginning from the rear and working forward with just enough threads to get them started, the left front hole in the block will not line up enough to get the bolt started. If I work from front to rear, the left and center rear bolts will not line up. The block does not appear to have been machined in any way that would move the location of any of the bolt holes. I've tried grinding a taper on the bolt to get it to start but it doesn't help. Anybody got any good ideas? I may have to go to studs but would like to hear from someone who might have had this problem before.
Studs are undesirable because this engine is installed in a model T and the engine setback into the firewall keeps me from lifting the head over the studs. If I should ever need to change a head gasket I would have to pull the motor to get the head off.
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I have had a few Cragar / Miller heads of the years still have 1 in use
I think you find not all the Cragar head gasket have the stud/bolt holes punched perfect they are not high volume most were made long ago you sometimes need to tide up 1 or 2 spots
 
Are you not concerned that the holes in the block are a course thread? I don't know this for a fact but would suspect it would be harder to get proper torque?
 
Jon said:
Are you not concerned that the holes in the block are a course thread? I don't know this for a fact but would suspect it would be harder to get proper torque?
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Ever looked at the bolt holes in a small block chevy or ford?
 
All engine blocks that I worked on are coarse thread. You would never use a fine thread for cast block.

I would get a .015 over size drill bit, and drill out the holes that are off. Or use a 15/32 on the hole that does not line up.
 
I don't know how thick the material is on the head you are talking about but Snyder told me they had occasional problems with bolt holes from the shop that machined the 5.5:1 heads before I took them over. They were not peck drilling them and so there was wandering of the drill. This may have happened with this head you have. It would most likely present itself towards the end of the drill's life. I use only carbide tipped drills and flood them with coolant and peck the drill at .150 per peck. I have had to start programs over after drilling is finished and when the drilling portion runs again there is no sound coming from the drill re-drilling the drilled holes. That's when you know you have things in order.

Tod
 
If it's a Denver Miller, I would suspect the head is off a little. I once had a new one and the push-rod holes were not drilled all the way through.
 
Jon said:
Are you not concerned that the holes in the block are a course thread? I don't know this for a fact but would suspect it would be harder to get proper torque?
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I agree that when tightening the coarse thread it will take a little more torque to arrive at the same clamping force.
 
I agree with Tom's statement. Clamping loads are less with course threads BUT also--
the maximum torque is also less!! Oh the fun of modifying!
 
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