355 to 305 downgrade. powerloss?
09-09-2004, 10:10 PM
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Car: 1988 Camaro
Engine: 350 V-Eight
Transmission: T5
355 to 305 downgrade. powerloss?
It looks like I am gonna be replacing the entire bottom end with a 305. Im using the same heads, cam, and intake. Will there be a noticable power loss? And Im only doing this to make the car drivable to sell it ,if your wondering.
09-09-2004, 10:26 PM
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Car: 89 IROC-Z
Engine: L03
Transmission: T-5
Axle/Gears: 4th Gen/3.42
A wise man once said ''theres no replacment for displacement''
Of course there will be a noticable power loss. But it should still make decent power. I'm assuming you're planning to use the 355 short block for another vehicle, so go for it, why not....
Of course there will be a noticable power loss. But it should still make decent power. I'm assuming you're planning to use the 355 short block for another vehicle, so go for it, why not....
09-09-2004, 10:34 PM
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Car: 1988 Camaro
Engine: 350 V-Eight
Transmission: T5
theres a problem with the 355, a good possibility the block is bad, and the crank and rods are used, so they might also be no good. I dont have the time or money to build a new one.
09-10-2004, 12:24 AM
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Car: 89 IROC-Z
Engine: L03
Transmission: T-5
Axle/Gears: 4th Gen/3.42
well, If your only concern is making it drivable to sell, i've got an L03 i'll part with at a great price. That way your car will be on the road AND you can keep your performance goodies. Of course, shipping might cost a wee bit.
09-10-2004, 12:26 AM
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Car: 1989 Trans Am
Engine: 355 HSR
Transmission: Pro-Built 700r4 w/ 3400 converter
Axle/Gears: 10 bolt w/ 3.42 gears
Dang dude... I hate that for ya. If I were you I would start looking for a 350 short block used from either a junk yard or from this board. Don't go backwards if you don't have to.
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09-10-2004, 11:17 AM
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Car: 1989 Trans Am
Engine: 355 HSR
Transmission: Pro-Built 700r4 w/ 3400 converter
Axle/Gears: 10 bolt w/ 3.42 gears
IIRC, the 305 heads are 58, so your compression will be down in the 8s w/ the L98 heads IF they are 64 cc. I can't off the top of my head recall the cc size on those. Are they stock l98s or aftermarket heads?
09-10-2004, 12:31 PM
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Car: 82 Z28
Engine: Al LT1 headed LG4 305
Transmission: TH350
Axle/Gears: 3.73 posi with spacer
Don't do it your compression will go down to the depths of hell. You will also lose about 15% power just from having less CID.
09-10-2004, 01:06 PM
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Car: 1988 Camaro
Engine: 350 V-Eight
Transmission: T5
I really dont care a whole lot about losing power, as long as it runs good, and dosent knock like mine is now. My goal is to sell the car. The 355 in it now runs like a 305, a 9.8 1/8 mile, and thats cuz of the cam I used. My friend is gonna give me the cam out of his L98 iroc-z to use instead, that will make a little more power.
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