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Brand new 300 HP 305 vs 350

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Old Nov 18, 2009 | 03:12 PM
  #1  
THEGunboundGod's Avatar
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From: new hampshire
Car: 1986 Z28
Engine: 305
Transmission: T5
Axle/Gears: 4.11
Brand new 300 HP 305 vs 350

So next year I'm planning on getting a new engine for the Camaro, cause I have no idea how to rebuild one. I remember seeing somewhere on a site a 300 horsepower 305 around $1000. Well if a 305 and a 350 had the same horsepower, would they still run the same? Does a 305 weigh dramatically less and save more fuel? I'd get a carborated one either way. And would I need any new parts, the car is already a stock 5 speed shifter hooked to a 305, will a more powerful engine destroy the gears or soemthing if I drive it too hard?

Brand new 300 HP 305 vs 350:
Price
Economy
Weight
Space
Power
Acceleration

Thanks for any wisdom you can give me.
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Old Nov 18, 2009 | 03:55 PM
  #2  
cIaRmOaCrZo's Avatar
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Joined: Aug 2009
Posts: 913
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From: greenfield indiana
Car: 86' IROC-Z....and 5 other 3rdgens
Engine: 383 hsr
Transmission: built 700r4
Axle/Gears: stock 3.23, 10bolt
Re: Brand new 300 HP 305 vs 350

dont quote me on this lol, but i beleive a 350 is lighter than the 305 due to the displacement of block material. yeah it has a slightly larger piston but pistons dont even compare to the wieght of cylinder wall material that is present on a 305. and everything else is virtually identical. including crank shafts.

like i said, dont quote me on this, someone correct me if im wrong. cuz iv never wieghed the engines on a scale haha
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Old Nov 18, 2009 | 03:58 PM
  #3  
ZONES89RS's Avatar
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From: Hou. TX
Car: 86 TA, 91 B4C
Engine: 5.3, 4.8
Transmission: 4L80 4000, T56
Axle/Gears: 4.30 M12, 23.42 10 bolt
Re: Brand new 300 HP 305 vs 350

Weight: The same

Price: 350 is cheaper

Economy: 350 should do better with a smaller cam making the same power as the 305

Space: Same size

Power: 350 will be better for drivabilty, but the torque should be greater for the 350 as well

Acceleration: 350 should edge out the 305 in the torque department

HTH
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Old Nov 18, 2009 | 04:19 PM
  #4  
five7kid's Avatar
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From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Originally Posted by THEGunboundGod
Well if a 305 and a 350 had the same horsepower, would they still run the same?
No. In order to make up for the lower torque, the 305 will have to produce the 300 HP at higher RPMs, meaning even lower torque in the lower RPMs. Meaning you have to rev the engine higher to get the car moving, etc., etc., etc.

Originally Posted by THEGunboundGod
Does a 305 weigh dramatically less and save more fuel?
A 305 and 350 weigh the same.

Given the operating characteristics in the paragraph above, a 300 HP 305 may actually use more fuel than a 300 HP 350.

Originally Posted by THEGunboundGod
I'd get a carborated one either way. And would I need any new parts, the car is already a stock 5 speed shifter hooked to a 305...
Not if your 350 was one-piece rear main style ('86-up).

Originally Posted by THEGunboundGod
will a more powerful engine destroy the gears or soemthing if I drive it too hard?
Transmissions are rated at the torque they can sustain continuously for 24 hours. The T5 is somewhere in the 275-300 lb-ft range. But, the primary cause of failure for T5's is shock, things such as high-RPM clutch dumps and speed shifting. Remember what I said above about the 305 needing to be at higher RPMs to get the car moving?

Basically, treat the T5 properly, and it will live just as easily behind either one.

Originally Posted by THEGunboundGod
Brand new 300 HP 305 vs 350:
Price
A 300 HP 350 would probably cost less than a 300 HP 305.

Originally Posted by THEGunboundGod
Economy
Most likely the 300 HP 350 would get better fuel economy, because it would need less cam to produce the 300 HP, and therefore require less gear to get the car moving.

Originally Posted by THEGunboundGod
Weight
305 and 350 weigh the same.

Originally Posted by THEGunboundGod
Space
A 305 and 350 are completely identical externally.

Originally Posted by THEGunboundGod
Power
Acceleration
A 300 HP 350 will outrun a 300 HP 305 in the quarter mile.

Last edited by five7kid; Nov 19, 2009 at 12:48 PM.
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Old Nov 18, 2009 | 09:40 PM
  #5  
THEGunboundGod's Avatar
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Joined: Sep 2009
Posts: 63
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From: new hampshire
Car: 1986 Z28
Engine: 305
Transmission: T5
Axle/Gears: 4.11
Re: Brand new 300 HP 305 vs 350

Wow thank you so much guys, it'll be a 350 then!
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