would TES be sufficent up to 325 to 340 hp?

 

doubt it, maybe if you change out the end of the "Y" pipe to flowmaster "Y", or if you got a bigger catback. 3.5", or had a freeflow catback like Borla.

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-Tas
'89 Formula WS-6

305, TBI, auto, 14x3 chrome flat based open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips....

To be installed eventually far far far into the future: Yours if the price is right and I don't have to ship :
Hooker 1-5/8" 50 state legal headers, Dynomax 3" I pipe (PN 44063 and 43248), Catco 3" cat, and injector spacer.

Super GRK_Taz World
F-Body Dual Exaust
EFI & Intake Options
AOL IM: superGRtaz

 

what are you doing to your 305 to get these horsepower levels out of curiosity? have you looked into a 350 or is this a daily driver?