Help!--head bolt identification
 

Need to know the difference between the torque to yield variety and standard torque. Ordered new bolts but think I got I the torque to yield variety. They have a smaller head on them and a cut down shank that tapers out to the threads. I'm thinking about reusing my old head bolts after I run then thru a die and some new anti-sieze. Need to get this thing together running out of time.

You have come this far on your project. Dont get hasty and use the old bolts, just use the TTY bolts as long as they are new. Just a little FYI 93-95 werent TTY bolts and 96-97 were. Just fire in the new ones bro, I dont think there is a way to visually tell the difference though. Good luck bud, dont go cheap when you already have the new bolts. Torque them to 65FT/LBS with a teflon based thread sealer in three seqential steps!!! Good luck ~~~rob

Do a search on this topic - it has been covered a lot lately. My 94 had torque to yield bolts in it. Do yourself a favour and use the bolts you purchased. They are an upgrade from the earlier style you pulled out of the engine. Although they look like the old style SBC bolts, they are not the same.

Do a search in the LT1 Tech forum under the post title "Okay To Re-Use Head Bolts On The LT1???" Enjoy the read :D

How did you know they were TTY bolts? As stated previously, they were not shown in any factory engine specs until 1996.

Because while trying to re-use them, one of them yeilded (stretched), which is a bit scary when the other option is that a thread pulled from the block. Fortunately it was the bolt. GM here in town doesn't advise re-using them.

The question still remains how do you physically identify a torque to yield bolt? The bolts I got from the dealership are TTY according to the part number but mine has the old style(95). TTY bolts have a reduced diameter on the shank which allows them to stretch while the standard bolts have the same thickness thru the shank. The other thing I question is according to the manual the TTY bolts get torqued to a certain spec. and then tightened to certain amount of degrees relative to the bolt. The TTY bolts are supposed to be superior allowing the bolts to stretch more accurately but I think I am just going to order some ARP's and say the hell with the factory bolts. Thanks for the input.

identification
 

The early bolts do not have a captive washer under the head. My LT-1 had bolts that looked like the early style, but had the captive washer. Apparently, that identifies them as TTY. In the industry there are many TTY bolts that do no use a reduced section, and are full diameter. Other TTY bolts in some cars can be re-used up to five times. GM will not supply the early style TTY with the captive washers. They now supply only the small hex, flange head style TTY for all LT-1 applications.

Thanks for the info, but what is the correct way to torque a TTY bolt. One is by the book setting the bolt in place with a small amount of torque then rotating it a cretain amount of degrees. The other I have seen is to torque it 65 ft. lbs. like the old way, but is this correct?

I forget the exact specs, but all bolts are torqued to an intial value in foot-pounds in sequence. Next, in sequence, the bolts are angle tightened. Long bolts to about 85 degrees, and short bolts to around 60 degrees. You'll have to find the specs - Felpro gives them when you purchase the bolts. After that you can forget about them until the heads come off again.