Manifold broken from SAIS block-off plates, Need repair advice

Installing block-off plates with Hewitt Bypass Kit, which I did as "preventative maintenance" on my 08 5.7L, unfortunately caused a broken manifold on the passenger side and a leak on the driver side, so now I'm having it all fixed at an exhaust shop (the best shop in my region as far as I know and they've done excellent work for me personally in the past). Looking for some feedback:

- Should I go OEM with the replacement manifold, or is Dorman good to go? Exhaust shop owner says he feels comfortable with Dorman. Passenger-side is "right side", correct?

- His approach for the repair is to physically remove the air injection lines/tubes and block off exhaust on each manifold itself with his own fabrication, while leaving it reversible in case SAIS is needed in the future. If need be, he can also fabricate covers for up top where the air injection lines connect to the air pump. Thoughts on this approach?

As a side question, Hewitt recommends blocking exhaust from the SAIS, and I guess I'll continue to do that since I'm already running their module, but I don't understand the technical reason why. Could someone plz explain why block that exhaust?

Side note, in hindsight I would have left the truck as-is and not done the bypass. I'm spending about as much money now as if I had to repair a broken SAIS, which may have never even broken. Take that FWIW.

 

My understanding is that the block off plates are there in case the switch valves get stuck open. This actually happened to me. I installed the bypass in 2019, all had been fine until Summer 2023 when the switch valves somehow got stuck opened. As I drove 700 miles home, and had to pull over 20+ times along the way to clear the codes (and cursing out Toyota Engineers for causing limp mode for a system that is only used for cold starts) I had wished that I installed those block off plates. I installed them as soon as I got home and all has been well since.

Sorry for your bad luck on this one.

 

Installing the block off plates makes sure no heat comes up to damage the pressure sensors which would throw a code. You can remove the switching valve if you get the needed pigtail which costs about $200 you would need 2

 

You can try Dorman, but they may not fit well because of the way the exit flange is welded on. The tube protrudes too far causing the cat pipe not to seal well, at least on mine.