is their any power mods for an 03c4500 with an 8.1 mated to an allison 5 sp

[ace777777777]

the truck has a huge air intake filter, id like to open it up and the exhaust up by getting rid of the huge muffler ,duling the pipes out to side and a power programmer i cant find any after market products , i dont want to trip any codes by opening up intake and exhaust anyone out there ever tried any of this, any experiential knowledge will be quite helpful the truck runs like crap. it only has 8000 on it ive been running 87 octane in it ,it sits a lot , just had a new powersteering pump put in it ,the brakes been not all that great . i hope the pump will solve that problem it all runs in the same system , brakes and the power steering .

[DmaxMaverick]

Welcome to the Forums!

BullyDog, Diablosport and Superchips support the GM gassers. You will have to contact the mfg or distributors for the specific model. Hypertech may work as well, but they don't list it specifically. TDP Advertisers that carry these brands should be able to order what you need, even if they don't list the application.

[Mark Rinker]

Personally, I'd take the truck to someone with a chassis dyno that is knowledgeable with 'EFI Live'. Have them build you a custom tune matched to your gearing and use of the truck.