Stock 305, thoughts on 3” tubing?

monte olrac

G-Body Guru
Feb 11, 2009
919
28
Wichita damn Falls Tx.
i would go with 2.5" duals with a x or h pipe its not going to kill the 3-5 performance (mainly because 305 and performance dont really mix) but if you ever decide to upgrade engines you will be able to support well over 400 with that setup.
 

Clone TIE Pilot

Comic Book Super Hero
Aug 14, 2011
2,686
113
Galaxy far far away
i would go with 2.5" duals with a x or h pipe its not going to kill the 3-5 performance (mainly because 305 and performance dont really mix) but if you ever decide to upgrade engines you will be able to support well over 400 with that setup.

Depends on which 305 and what other mods have been done. An HO 305 has 2.25 exhaust and might see a couple more HP with a 2.5 exhaust. If the HO 305 has cam, intake, or header upgrades then a 2.5 exhaust would have a little more benefit. But on a typical stock LG4 305, there won't be much benefit with a 2.5 yet alone a 3 inch exhaust.
 

monte olrac

G-Body Guru
Feb 11, 2009
919
28
Wichita damn Falls Tx.
Depends on which 305 and what other mods have been done. An HO 305 has 2.25 exhaust and might see a couple more HP with a 2.5 exhaust. If the HO 305 has cam, intake, or header upgrades then a 2.5 exhaust would have a little more benefit. But on a typical stock LG4 305, there won't be much benefit with a 2.5 yet alone a 3 inch exhaust.
Even an ho 305, still has ridiculous low hp, that unless for sound or if someone decides to add an power adder exhaust isnt going to change anything that you will notice. assuming asking about the exhaust i feel future upgrades are probably going to happen with his build
 

Clone TIE Pilot

Comic Book Super Hero
Aug 14, 2011
2,686
113
Galaxy far far away
190 hp is decent power for an 80's car and with the 9.5 CR they respond better to improvements than most 305s. The stock exhaust manifolds and LG4 cat converters are bigger restrictions to HP than the exhaust pipe sizing.

Main point is that because 305s are smaller than 350s, they don't need big pipes. Headers and a L69 cat converter would be better exhaust upgrades than bigger pipes.
 

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