Why would I not have more hp & torque after a 305 TBI to 350 TPI swap
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From: Michigan
Car: '89 Camaro RS convertible
Engine: 5.7 TPI
Transmission: 700R4
Axle/Gears: 4.10
Re: Why would I not have more hp & torque after a 305 TBI to 350 TPI swap
I would take great heads all day long over 13 cid. On avg. most street type performance engines will only avg. out 1 to 1.5 HP per cubic inch.
So going from a 360 to a 383 is only 13 cid and will only gain you 13 to 20 HP.
A good set of heads will gain you 40-80 HP over your stock ones. Like say a set of vortec heads, you are looking at around a 35-45 HP gain. A set of Brodix IK heads around a 60 HP gain, a set of AFR heads around a 70-80 HP gain.
Heads are the #1 highest hp gain part (other than nitrous, turbo, supercharger) you can add.
So going from a 360 to a 383 is only 13 cid and will only gain you 13 to 20 HP.
A good set of heads will gain you 40-80 HP over your stock ones. Like say a set of vortec heads, you are looking at around a 35-45 HP gain. A set of Brodix IK heads around a 60 HP gain, a set of AFR heads around a 70-80 HP gain.
Heads are the #1 highest hp gain part (other than nitrous, turbo, supercharger) you can add.
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From: North Central Indiana
Car: 86 IROC
Engine: 383
Transmission: TKO 600
Axle/Gears: 3.54 Dana 44 IRS
Re: Why would I not have more hp & torque after a 305 TBI to 350 TPI swap
A 383 even with stock heads will make more bottom end torque than a 350 with good heads. I'm talking 3000rpm and below. If I were in your shoes I guess I'd go with the stroker and stock heads. You can always change the heads out later.
Thread Starter
Junior Member
Joined: Jul 2013
Posts: 70
Likes: 0
From: Michigan
Car: '89 Camaro RS convertible
Engine: 5.7 TPI
Transmission: 700R4
Axle/Gears: 4.10
Re: Why would I not have more hp & torque after a 305 TBI to 350 TPI swap
I decided to go with the stroker. I had my transmission rebuilt and it ended up being less than what originally quoted so maybe I can get some heads to.
Thread Starter
Junior Member
Joined: Jul 2013
Posts: 70
Likes: 0
From: Michigan
Car: '89 Camaro RS convertible
Engine: 5.7 TPI
Transmission: 700R4
Axle/Gears: 4.10
Re: Why would I not have more hp & torque after a 305 TBI to 350 TPI swap
Anyone have any suggestions on a good cam. I was planning on using a comp cam just not sure which exact one I should go with.
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iTrader: (9)
Joined: Sep 2001
Posts: 2,984
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From: North Central Indiana
Car: 86 IROC
Engine: 383
Transmission: TKO 600
Axle/Gears: 3.54 Dana 44 IRS
Re: Why would I not have more hp & torque after a 305 TBI to 350 TPI swap
268XFI HR13. make sure the heads have enough valve spring to run this much lift. my second choice would be the 260XFI HR13...
Thread Starter
Junior Member
Joined: Jul 2013
Posts: 70
Likes: 0
From: Michigan
Car: '89 Camaro RS convertible
Engine: 5.7 TPI
Transmission: 700R4
Axle/Gears: 4.10
Re: Why would I not have more hp & torque after a 305 TBI to 350 TPI swap
The 268 is the one the builder suggested but I had the wrong part number so comp cam told me it wouldnt fit my block and they suggested the 260 one I'm buying roller tip rockers and springs if needed so I'll probably go with the 268 but comp asked if I need a small base circle cam for the 383
Thread Starter
Junior Member
Joined: Jul 2013
Posts: 70
Likes: 0
From: Michigan
Car: '89 Camaro RS convertible
Engine: 5.7 TPI
Transmission: 700R4
Axle/Gears: 4.10
Re: Why would I not have more hp & torque after a 305 TBI to 350 TPI swap
I just bought an engine that was already built from a friend that wrecked his car. Its a 355 full roller high flow runners edelbrock heads. Now im not sure if my exhaust will fit with the extra quart oil pan or the oil cooler. I can probably modify the exhaust to fit the pan but do I really need the cooler?
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