hello, i have a new set of felpro head bolts and my question is can i just torque them down at 20lb-40lb-65lbs and be done, or do i have to use tty 20lb then 80deg uppers 67deg lowers? also if you torque a head down and loosen bolts al the way is head gasket shot?

 

What year engine? Later engines used TTY (Torque To Yeild) bolts that are meant to use the second torque/angle method for tightening.

In the future use a signature or provide more info on what you are working on, so people don't have to ask.

 

sorry,the car is a 97 formula lt1.

 

the reason i ask is because when you look at head bolts, the part numbers for 1994 to 97 are the same so why would the 94-95 be torqued different 96-97?

 

I'll have to crawfish on that one as I have noted the same thing (just forgot about it). Basically it seems like they just changed the torquing method (in 1996). However, on other cars, there are bolts that are specifically TTY and cannot be reused and use the TA method of tightening. You can use either method, IMHO, as long as the bolts are not TTY. TTY bolts are usually a little different looking from regular bolts.

The TTY method is supposed to be the better one and give more uniform clamping force. It could be that GM went to that method to alleviate head gasket failures from using aluminum heads on a cast iron block. I used the TTY method with my ARP bolts when I reassembled my engine.

 

You need to follow federal mogul's torque specs for the bolts you bought and the application.

What GM specifies for the bolts they used on the assembly line or the bolts they provide as replacement is irrelevant.

 

most all the manufacturers make tty bolts only. they fit 94-97 lt1s so why make another style that fits 94-95 that can be reused. if they only make single use bolts that also means more repeat business. Use your felpros and use the torque angle method or go get some ARP head bolts and torque in 3 steps. I went the ARP route. That was before i knew mine were reusable tho.