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post #1 of (permalink) Old 12-06-2002, 09:03 AM Thread Starter
 
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305 Exhaust

I have a friend who is going to put an exhaust system on his 84' Firebird, it has a 305 and I was wondering what size pipe would be best for him so he doesn't lose a ton of torque but he still gains power, he is not sure on whether to go dual or single. I was thinking Flowmaster 40s for muffs but am open to suggestions for a good loud sound.
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post #2 of (permalink) Old 12-06-2002, 07:16 PM
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Re: 305 Exhaust

I know it's about impossible to run true duals on those Gen III F-bodies. Just not enough clearance and room. So basically you can run a single exhaust back to the muffler in the rear, and if he wants, split it there.

This motor been breathed on at all? If it's stock, don't go much wider than 2.5". If he wants the duals look, go for 2.5" back to the muffler, then 2" duals out of the muffler. Mandrel bent with welded seams of course.[img]images/graemlins/cool.gif[/img]
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post #3 of (permalink) Old 12-06-2002, 08:21 PM Thread Starter
 
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Re: 305 Exhaust

We went and got this quoted today:
3" pipe from cat back
Flowmaster Muff
Dual 2.5" out of muff

Total: $375
Does that sound about right
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post #4 of (permalink) Old 12-06-2002, 08:32 PM
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Re: 305 Exhaust

I dunno about that main pipe. Seems kinda wide for a early 80's 305. You're talking like 150hp bone stock, brand new. Too wide of a pipe and you'd loose back pressure and while you might gain SOME high end hp, low end torque would suffer.[img]images/graemlins/tongue.gif[/img] That trade off might be fine for him, but I wouldn't do it. 2.5" is what I'd go with. The 2.5" tips are no big deal. On the 3rd Gen F-bodies the tail pipes out of the mufflers are only like 2' long at most. So half an inch won't hurt much.

If he had a high-po 350 waiting to go in, then the 3" would work for now, but if that 305 is staying in and not getting to radically built, stay with 2.5".
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post #5 of (permalink) Old 12-06-2002, 08:34 PM
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Re: 305 Exhaust

I'd go with 2.25" duals. I'd do 3" if he was keeping the manifolds (waste). You can get Hooker headers for $150.

Single-in dual-out mufflers are gay. All that it provides is more junk to rust off. There is no performance to be found. I'm no fan of Slushmaster mufflers either.
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post #6 of (permalink) Old 12-07-2002, 01:35 AM Thread Starter
 
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Re: 305 Exhaust

The motor doesn't have much torque to begin with so all he wants is some more power at rpms. It's hard to run two mufflers on the 3rd gens because of the gas tank getting in the way.
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post #7 of (permalink) Old 12-07-2002, 12:22 PM
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Re: 305 Exhaust

Yeah, it isn't easy, but you can find dual pipe kits from Summit so it must be possible. I've only seen one thirdgen with dual exhaust and it had glass.

He can add a 2" carburetor spacer to get some more top-end out of it.
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post #8 of (permalink) Old 12-11-2002, 10:11 AM
 
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Re: 305 Exhaust

arent 305's generally doggy engines and kind of a waste to build? [img]images/graemlins/blush.gif[/img]
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post #9 of (permalink) Old 12-11-2002, 01:29 PM
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Re: 305 Exhaust

It's getting hard to find a good 350 to rebuild in Michigan. Most of them need serious machine work that are for a reasonable price ($50-$150). Even the "good" $200-$500 ones need a serious rebuild. It's actually cheaper to buy a vehicle with a 350 in it than it is to buy just the motor these days. For what a lot of these people want for used motors (that you can't even hear run most of the time) it's cheaper/easier to go buy a shortblock from GM. A lot of the time you still come out ahead by buying a longblock.

You can rebuild a 305 for about the same price and you can get 250 horses out of a 305 without trying. People usually give 305s away.
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post #10 of (permalink) Old 12-11-2002, 02:33 PM
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Re: 305 Exhaust

I've got a 305 you can have.
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