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305tbi upgrade opinion.

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Old 08-27-2011, 06:36 PM
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Car: 1992 Firebird convertible
Engine: 5.0 tbi
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305tbi upgrade opinion.

i know 305 is patheticcc but im think edlebrock mani, headers, cat delete and 3.42 in the rear. already have flowmaster catback and a k&n filter. will i notice a gain?
Old 08-27-2011, 08:24 PM
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Re: 305tbi upgrade opinion.

The swap from 2.73 to 3.42 ratio will make a big difference off the line and adds allot to the fun factor/seat of the pants feel. Install a Eaton Posi.while your at it and a L.P.W. support cover. IMO, as far as engine modification gos I would only add pieces that can be swapped over to a 350 when the time comes.The plan you have above is basically right on the money and should be done to any and all 5.0s. Not so sure the cat delete is necessary if you go with a high flow Magnaflow cat.(when you say K&N filter do you mean "open element" with K&N or are you still running the stock set-up)?

Last edited by Ron U.S.M.C.; 08-27-2011 at 08:42 PM. Reason: add info.
Old 08-27-2011, 08:25 PM
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Re: 305tbi upgrade opinion.

Yes. The gears will give the most gain. I would throw in a Corvette or S10 torque converter while your at it. You can pick them up at any parts store few a few hundred bucks. Combine that with better gears and your other mods and it should start to come alive. Another item to consider would be an adjustable fuel pressure regulator. A tune would help get most out of all your parts, but it's not totally necessary.
Old 08-27-2011, 09:46 PM
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Car: 1992 Firebird convertible
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Re: 305tbi upgrade opinion.

im still running stock set up for the aircleaner, just had a k&n in it. if i switch to open element, what bout the crap hoookedup to the bottum of the air cleaner?


And i forgot, i got corvette servos and idk bout the converter. i didnt install tranny
Old 08-27-2011, 09:56 PM
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Re: 305tbi upgrade opinion.

the crap on the bottom of the air cleaner. wont be needed if you run an open element and dont have to pass a visual inspection. you just follow the vacuum hose to its source and cap it.
Old 08-28-2011, 01:24 PM
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Re: 305tbi upgrade opinion.

why is it even there? lol and whats the wire plug thing do?
Old 08-28-2011, 07:02 PM
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Re: 305tbi upgrade opinion.

wire and plug? you must mean for the intake air temperature sensor. that does need to be retained. you can drill out a hole and mount it in your open element filter.
Old 01-31-2012, 08:53 PM
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Re: 305tbi upgrade opinion.

Do they make vacuum line caps?
Old 01-31-2012, 10:36 PM
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Re: 305tbi upgrade opinion.

It all depends what your budget is. The gears would make the biggest gain. I would go with 3.73's though. I mean you do have overdrive. Then I would say a cam with the manifold and a good tune along with bumping up your fuel pressure. Then I might look into getting headers and a high flow cat. I am in Texas too and it is just a matter of time before you will have to get a sniffer test to get your tags. I put a 3 inch cat on my truck. It doesn't hurt it a bit and it was 50 bucks.
Old 02-01-2012, 02:06 AM
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Re: 305tbi upgrade opinion.

Here we go again..........read the cardomain and call it a day.
Old 02-01-2012, 10:39 AM
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Re: 305tbi upgrade opinion.

@robertfrank what's your car run in the 1/4?
Old 02-01-2012, 05:25 PM
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Re: 305tbi upgrade opinion.

Originally Posted by Dougie91
Do they make vacuum line caps?
Yeah just trace the line back to where it goes, and cap that fitting off, and you're done.
Old 02-01-2012, 05:30 PM
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Re: 305tbi upgrade opinion.

Like everyone else has said you'll get the biggest notice from your gear change. When I went from a 3.08 to a 4.10 it was a huge difference.
Old 02-02-2012, 02:59 AM
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Car: 1988 camaro "SS"/ 1991 305/T5
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Re: 305tbi upgrade opinion.

Originally Posted by Dougie91
@robertfrank what's your car run in the 1/4?
well before the H/C/I and converter swap I was running an estimated 14.3-14.1 in the 1320 and I haven't had a chance to get it to the track since then but I can definitely guarentee that it a mid to low 13 second car. It's surprised me and many people on how damn quick it is. The engine is basically a baby ZZ4.
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