Main cap studs / Oil pickup mount

[lhearold]

I have a Magnum based 408 CI stroker that I will be putting into my Dart. The engine is a fresh rebuild and has not been run since being assembled as a stroker. It currently has the stock bolts in the main caps. I need to replace the bolts with studs so I can mount the oil pump pickup support bracket. I have heard that since the motor was line bored with the bolts, I cannot replace them with studs unless I get the block line bored again. Is this true? I have also heard that, as an alternative to putting in studs, I can weld a bolt to the top of the main bearing bolt in the #3 position to hold the pickup support. Will welding weaken the main cap bolt? Is it acceptable to do this?

Also, will the main stud kit for the LA work on the magnum?

Thanks,

Larry

[440 ValiantCharger]

I have heard that since the motor was line bored with the bolts, I cannot replace them with studs unless I get the block line bored again. Is this true?

Yes this is my understanding of bolts v studs also.

I have also heard that, as an alternative to putting in studs, I can weld a bolt to the top of the main bearing bolt in the #3 position to hold the pickup support. Will welding weaken the main cap bolt? Is it acceptable to do this?

Yes I would think that welding would weaken the bolt.

Can you just install the studs on the number 3 cap would this make much difference to the bearing clearences.?

[ksdartguy]

Ive changed out bolts for studs on a couple BBs and never changed a thing.
On the other hand, a nut tacked to a bolt head shouldnt hurt your bolts strength.
Start with a good bolt though. Not factory ones.

[bOb shingler]

this is what i don't understand about installing studs and having to get the block alignhoned. the caps are located by the machining in the block not by the bolts so why would changing the hardware change the alignment? 

[65bcuda]

I added ARP studs to my 408 build after machining of the block and it did not effect the clearences. Maybe for a full race application it may matter but for a street ride should not.
I may be wrong, but I'm sure someone here will say for sure.

[NYrr496]

I've done three 440's and a couple of chevy small blocks with studs... Didn't line hone any of them, never had a problem.

[67 dartgts]

Hello:

this is what i don't understand about installing studs and having to get the block alignhoned. the caps are located by the machining in the block not by the bolts so why would changing the hardware change the alignment?

bOb shingler
said that

Got to agree with Bob on this.  Putting in studs should not cause any misalignment.  I'd put the studs in ,if that's what you want to do and forget it.

       Maynard

[68_Val_Sedan]

from what I understand the engine builders hone the bolt holes i nthe caps so you can remove the caps with the studs still in the block ... I however never have had any luck in removing the main caps with the studs still in the block,  so I quit having the caps honed ...

[dodgeboy]

I think you can get away with studs as long as you don't torque them any more than what the regular bolts had. On my last 440 build I used ARP main studs and the recommended torque on them is considerably higher than the regular bolts. My machinist said this pulls the main bearing bores slightly out of round and for this reason he recommended a line hone and I followed his suggestion. However I think the engine would have lived just as well without it and I don't think it was really necessary.

If you have a dial bore gauge and just for your peace of mind you could torque them with the ARPs and if they are still round you'll know you're ok.

Roger