ARP main bolts

[blarson]

I tried using the SBi stretch bolts my machinist sold me in building up the bottom end of my pushrod 3.4 and ended up with some serious torque scatter while doing the 77degree step 2 torque (40 ft pound variation) despite using ARP ultra torque. After removing the bolt they were stretched randomly between .000 and .007 beyond their original length leading me to believe that their elastic limit had been exceeded and that they need to be replaced. I've already line bored the block so studs are out of the picture.

I've been in contact with a guy over at ARP to help figure out what was happening and to get main cap bolts to replace the ones I have. He sent me a spreadsheet to work out what I need to order. Trouble is, I don't know how to measure the thread pitch deep inside my main cap bolt holes directly or how to measure the length of thread inside the block. Does anyone have any suggestion regarding the proper way to measure these or alternately the specs themselves?

btw, the chevette here is the one receiving the 3.4. http://bangshift.com/blog/race-galle...-buck-fun.html

[SappySE107]

11Mx1.5 is the thread pitch and size.

[geoffinbc]

Never herd of that brand. Where are they made and what kind of power level do you intend to make? If your not running boost then stock bolts will be more than up to the challenge.

[ForcedFirebird]

If you change fasteners from the ones you used when aline boring, then you will probably need an aline bore again - specially if the torque value changes.

SBi is a OEM replacement bolt - they make valves and such as well (kind of like Sealed Power).

TTY bolts are not accurate enough to measure stretch as you would with studs.