What size header bolts for LT4?
 

Im looking around summit and getting together my total package on what I need to buy for my upgrade. What size header bolts do I need for my LT4? I see tons of different type of Breslin Locking Header Bolts on Summit but they dont have a choice for Gen II engines only Gen I.

Also where can I find cheap coated header extensions? Is it cheaper to do it on my own or just buy a package from Exotic Muscle or something? Im tying into Corsa Exhaust.

I used 1in ARP 12 point header bolts. Of course the on bolt where the brackets go I used a 2.5in grade 8 bolt from Home Depot.

As far as extensions that depends on your muffler shop. I have a complet custom system that bolts directly into the header collectors. With a Corsa system since I wouldn't really want a muffler shop hacking on it I would tell you to go ahead and get the EM extensions. You know they will fit right and not give you any hassles but they are overpriced IMO. There are no other cheapo extensions short of going down to the muffler shop and having some fabbed up.