[flyingfrizzle]

I am running 1/2" NAS bolts in my race car four-link brackets and they are rated at 180,000 psi each. There are only four bolts on each side holding the rear axle under the car with 20" wide slicks that see tremendous strain. My car is only 800 hp for now but the 2000-3000 HP promod cars run the same set up. Many guys run just grade 8 bolts. If 4 1/2" bolts can hold up to that your motor should be no problem. You can go on ebay and find some real nice NAS or AN stainless steel bolts for pennies on the dollar if you want something super strong and are worried. Most of them are in the 150,000 psi range for stainless.