hi, i have a b&s engine model#197412 thats on a homelite gen. i replaced the head gasket and need the bolt sequence to finish it up. i broke a bolt on it and was also wondering if i could use a longer or shorter bolt to replace the old one. will

Yes as long as the threaded part is long enough to engage the threads in the head to apply proper torque and the bolt hole you are putting it is open all the way through so as no damage to head or cooling fins will occur when bolt is tightened down.

Torque spec for your head bolts is 165 in/lbs.

http://www.hobbytalk.com/bbs1/attachment.php?attachmentid=35237&stc=1
Torque_Seq.pdf