What to expect 305 -> 350, performance wise?
01-17-2007, 07:44 AM
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Car: 91 Z28
Engine: 350
Transmission: 700r4
Axle/Gears: Stock
What to expect 305 -> 350, performance wise?
So were almost finished with the swap...probably actually turn the key and wonder why its not working...TODAY! (but damn its cold out!)
Anyway...so Im kinda excited...and I was wondering what type of performance gains I should expect?
It was plenty quick for me with a 305, and a shift kit...it was rock stock...as is this 350...of course it still has the shift kit in it, and Ive done the heater hose bypass mod on the TB...no other mods...
Should I expect a *truly* noticeable difference swapping a stock 305 to a stock 350?
Anyway...so Im kinda excited...and I was wondering what type of performance gains I should expect?
It was plenty quick for me with a 305, and a shift kit...it was rock stock...as is this 350...of course it still has the shift kit in it, and Ive done the heater hose bypass mod on the TB...no other mods...
Should I expect a *truly* noticeable difference swapping a stock 305 to a stock 350?
01-17-2007, 09:27 AM
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Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
That would depend on what stock 305, and what stock 350.
If you took out a L69 or LB9 and put back in a 76 Nova 350 2-barrel, then you downgraded yourself from 190 HP to 165 HP but picked up some torque at low RPMs.
If you took out a LG4 or L03 and put back in a 70 LT1, then you went from 145 HP or whatever, to about 325 HP; and it won't be hard to predict what you'll feel.
"Stock" covers ALOT of ground. It is beyond meaningless to use that word by itself to describe a motor. "Stock LB9", "stock 1983 truck 350 4-barrel with the TPI on top", "stock Goodwrench phone-company-van replacement motor", those have meaning; but "stock" in a vacuum is worthless.
If you took out a L69 or LB9 and put back in a 76 Nova 350 2-barrel, then you downgraded yourself from 190 HP to 165 HP but picked up some torque at low RPMs.
If you took out a LG4 or L03 and put back in a 70 LT1, then you went from 145 HP or whatever, to about 325 HP; and it won't be hard to predict what you'll feel.
"Stock" covers ALOT of ground. It is beyond meaningless to use that word by itself to describe a motor. "Stock LB9", "stock 1983 truck 350 4-barrel with the TPI on top", "stock Goodwrench phone-company-van replacement motor", those have meaning; but "stock" in a vacuum is worthless.
01-17-2007, 09:39 AM
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Car: 91 Z28
Engine: 350
Transmission: 700r4
Axle/Gears: Stock
I think it was an LB9 305, and we just got a crate 350...with no performance options...the TPI and everything is the same as it was on the 305.
I guess it was a silly question...
I guess it was a silly question...
01-17-2007, 09:41 AM
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Car: 1988 Iroc-Z / 1992 RS
Engine: 5.7 TPI / L03 TBI
Transmission: 700r-4 / 700r-4
Axle/Gears: 9 bolt 2.77 posi / 10 bolt 2.73
Did you use a 350 sensors (knock and esc) and have you upgraded the fuel supply?
01-17-2007, 10:02 AM
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Car: 1988 Iroc-Z / 1992 RS
Engine: 5.7 TPI / L03 TBI
Transmission: 700r-4 / 700r-4
Axle/Gears: 9 bolt 2.77 posi / 10 bolt 2.73
Does the new engine have flat tappet cam or roller?
It should be better all around on power. Should be about the same on fuel mileage as the 305 until you get use to the power and start pushing it harder.
It should be better all around on power. Should be about the same on fuel mileage as the 305 until you get use to the power and start pushing it harder.
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01-17-2007, 10:17 AM
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Car: 87 Firebird
Engine: 5.3 76mm
Transmission: Rossler TH400, PTC converter
Axle/Gears: Strange 12bolt, 3.08s
Im thinking that your going to spin the tires a little easier now 
Its going to feel alot better down low. Did you do anything else while you were in there, like headers?
Its going to feel alot better down low. Did you do anything else while you were in there, like headers?
01-17-2007, 09:34 PM
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Car: 1988 Iroc-Z / 1992 RS
Engine: 5.7 TPI / L03 TBI
Transmission: 700r-4 / 700r-4
Axle/Gears: 9 bolt 2.77 posi / 10 bolt 2.73
I would for sure find out if it is a roller cam or not. If it isn't roller and I'm pretty sure it isn't. You will need to break the camshaft in if not bad things can happen. Hate to see you having to replace the valve train and send all the metal shavings in the engine / bearings.
01-18-2007, 07:30 AM
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Car: 91 Z28
Engine: 350
Transmission: 700r4
Axle/Gears: Stock
The invoice says its a roller cam...heres the specs on the engine I bought:
http://www.rebuilt-auto-engines.com/...43107017706.22
http://www.rebuilt-auto-engines.com/...43107017706.22
01-18-2007, 02:19 PM
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Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
My brother bought that engine from them. It's a roller cam.
Hopefully you got 083 heads with it.
You should be pleasantly surprised.
Hopefully you got 083 heads with it.
You should be pleasantly surprised.
01-18-2007, 03:59 PM
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Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Depending on the cam they used, that should be more or less identical to the 350 that you would have got stock as a TPI one. So yeah, it could be A WHOLE LOT worse. Should make a noticeable improvement.
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