The best way to prevent a blown hg is to come up with a crossover elimination. Toyota really biffed it with the stock crossover. It dumps the exhaust from the passenger side BACKWARDS into the drivers side manifold.
remove x-over, weld up the manifolds, make a custom passenger side exhaust pipe to come down and cross over and join to the main pipe under the transmission.
remove x-over, weld up the manifolds, make a custom passenger side exhaust pipe to come down and cross over and join to the main pipe under the transmission.
"total - 0.00" 
