Do head studs add any stability to the block? I understand how studs are easier on threads if heads are removed alot and how they are better for high cylinder pressures. But I was talking to the guy who is boring/honing my 400 sbc and he was telling me how important it is to use a torque plate on a 400. He said on a 307 the cylinder don't distort much because of the small bore and having more metal between the cylinders when bolting a torque plate on. But on a 400 he said when the torque plate is in place it moves the cylinders quite a bit. So I was just wondering if using head studs would be better than arp bolts.

 

For most people. using bolts is fine. I currently have studs in my engine because it's easier on the threads in the block. I don't like doing thread repairs. My heads come off at least once a year.

When removing a head that has studs, all the studs have an allen key hole in the top of them. The studs are removed before the head is removed. Only if you had a very open engine like in a dragster can you leave the studs in the block.

 

I understand that Stephen. Mostly what I am wondering is when a stud is threaded into the block, heads installed and then the nut is torqued down, does the top of the bore distort less than when a bolt is threaded down into the block and torqed down?

 

Studs are slightly better.

The bore size & distortion stuff is bunk. It has more to do with deck thickness. If anything, the siamesed cylinders of the 400 would tend to stiffen each other, whereas the free-standing cylinders of the 4" & smaller bores would not.

You should hone with a torque plate, however, regardless of block.

 

I know it was'nt asked, but I'll offer this. Unless this is a dedicated race car that gets torn down regularly, use bolts. I did alot of research on using studs and the common response was having seepage problems, guy's switched back to bolts and the problem went away. There plenty of engine running bolts with alot more compression and output than I'll ever have with no problems so I'll stick with the KISS principal on this issue, just my opinion.

Just something to think about before jumping into head studs, what could be an easy fix to remove a head in car now turns into a chore with studs, even with the allen keyed heads it adds alot of time to the process and for practical purposes they just dont offer many benefits that outweigh the drawbacks.

 

Sounds good to me guys, I guess I am just overthinking a simple question. I guess the guys I bought the block from had plugs installed in the water passages to stiffen the deck up. Just looking for any advantage with a stock block. Thanks

 

I thought the main perk of studs was when tightening down, you aren't twisting the 'bolt', so you get more clamping load... (also, using fine threads on the top end...)
and I thought when removing the heads, you'd keep the studs in the block, so you can guide the head on/off easier... However, that makes sense if you don't have the room, to not do that...

 

My Dart block has a very thick deck so distortion isn't an issue. All the head bolt holes are also blind so none of them go into a water jacket. Just bonuses of buying an aftermarket block.

Yes, using studs has better clamping force because you're not tightening the bolt by twisting it into the threads in the head. The nut on top being tightened will still stretch the bolt to it's clamping force but it doesn't twist the stud like a bolt will.

It's the same as installing a harmonic balancer on the crank. If you use a bolt to pull it in, you risk stripping the threads in the end of the crank. A threaded rod screwed into the crank then a nut and washer used to push the balancer on won't have any problems. The nut is screwing down on the threads. A bolt is trying to force the balancer on while also trying to pull itself into the crank. Now think of that as head bolts/studs with a lot more torque. The course thread head bolts can grab a lot more metal so the risk of stripping is greatly reduced but it's still twisting the bolt.

As mentioned above, for long term use, put some bolts in. If it's a race engine that will see frequent tear downs, use studs. Nothing worse than seeing someone rebuild a 20+ year old engine and still uses the original head bolts. Even if you buy new factory head bolts, it will be better than using old ones.