Are they from the 4.3/5.7 or 7.4?
Thanks

They are from a 7.4 454

They have special injectors too. The Trucks run 9-12 psi. The Mercs run up to 30psi

Interesting. I had them checked a few years ago by Dr. Injector and one was bad. He had a replacement. I wonder what it came from, I doubt he's ever seen a 575.
Think there's anything to gain by letting TBI rework my TB's?

Use CFM tech, they will modify your tbody adapter plate as well. Stockers flow 670 cfm and their modified Tbodies flow 720. I am running a fuel pressure nearing 40psi. PM me if you want more info.

CFM is who I was meaning. Doah! Think I can get more boost with slightly larger TBI's? Would I gain anything by having them mod mine? I only rev to 5350. X-Mas wish list is TBS 250's and maybe the CFM's. Everything works great as is so If I'll gain nothing I won't do it. THEN what to spend $$$ on???