From 305 To 350
04-29-2004, 08:06 PM
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Car: '88 IROC-Z
Engine: 305 tpi
Transmission: 700r4/OD
From 305 To 350
I hope this is the right forum.
If a person changes his 305 to a 350 and he's not too worried about emission laws, would it be better to use the TPI set-up (from the 305) or do away with all the computer, smog, wiring harnesses, and fuel injection and use a carb set-up?
The reason I ask is I'm wanting to make it simple for me to "tinker" with and adjust.
The computer controlled 700r4/OD is also a concern if you do away with the computer, right?
I'm sure these questions have been asked before but, I'm sure you guys probably won't mind answering them again.
Any thoughts?
If a person changes his 305 to a 350 and he's not too worried about emission laws, would it be better to use the TPI set-up (from the 305) or do away with all the computer, smog, wiring harnesses, and fuel injection and use a carb set-up?
The reason I ask is I'm wanting to make it simple for me to "tinker" with and adjust.
The computer controlled 700r4/OD is also a concern if you do away with the computer, right?
I'm sure these questions have been asked before but, I'm sure you guys probably won't mind answering them again.
Any thoughts?
04-30-2004, 09:37 PM
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Some may argue, but I say keep the TPI regardless. Stock for stock, It'll give you better performance, lower emissions, and better fuel economy.
Start reading on how to tune your own chips, and the tunability of the EFI is pretty much limitless. You can tell the car exactly how much fuel and spark advance you want at an exacting RPM/load, and it doesn't have to be a linear climb either.
May be a little more intimidating at first compared to a simple carb setup, but it'll be better in the long run.
Good luck
Start reading on how to tune your own chips, and the tunability of the EFI is pretty much limitless. You can tell the car exactly how much fuel and spark advance you want at an exacting RPM/load, and it doesn't have to be a linear climb either.
May be a little more intimidating at first compared to a simple carb setup, but it'll be better in the long run.
Good luck
05-01-2004, 11:05 AM
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Car: '88 IROC-Z
Engine: 305 tpi
Transmission: 700r4/OD
I sure appreciate that info on TPI and I agree to an extent. I'd like to hear some of the arguments between these 2 selections because I know there's some one who doesn't agree. You know, the pros and cons
05-01-2004, 12:24 PM
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Car: 4
Engine: 6
Transmission: 5
TPI itelf is identical on the 305 and 350. Same intake base, runner, plenum, throttle body, etc. It all bolts right up, with the possible exception of the 86-back vs 87-up vs 96-up intake bolt pattern, which isn't specific to TPI anyway.
The only difference is the injectors flow rate (19 lbs/hr vs 22 lbs/hr), the knock sensor which is nothing more than a little microphne that's "tuned" to "hear" the particular pitch that spark knock makes which is in turn a function of the bore, and the chip programming. Use a cam in your 350 that's designed for TPI, and change those 3 things, and go for it.
Personally I despise TPI; but that's beside the point. If you have a car that has one in it, and it's all there and not hacked to death and works right or at least close, and you don't know what to do to change it, then it's still best to use it and make it the best it can be.
The only difference is the injectors flow rate (19 lbs/hr vs 22 lbs/hr), the knock sensor which is nothing more than a little microphne that's "tuned" to "hear" the particular pitch that spark knock makes which is in turn a function of the bore, and the chip programming. Use a cam in your 350 that's designed for TPI, and change those 3 things, and go for it.
Personally I despise TPI; but that's beside the point. If you have a car that has one in it, and it's all there and not hacked to death and works right or at least close, and you don't know what to do to change it, then it's still best to use it and make it the best it can be.
05-01-2004, 03:01 PM
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Car: '86 TA wrapped in '84 skin
Engine: 305 carbed
Transmission: 700R4
Axle/Gears: unknown
dont mean to thread jack but I could just throw a 350 under the 305 TPI intake stuff and it would all built right up?
05-01-2004, 03:14 PM
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Yes, as long as the intake is post 87 and the block is post 87, or vice versa. You can get them to interchange with about 10 min. of grinding, but then it wouldn't be a direct drop in
I'm not a huge fan of "tuned port" either, the long runner length tends to make it very torquey at low rpm, and fall flat about 3500 rpm. You can counter that by running a non-tuned port intake such as the one I am making, or running something like the LT1 intake or stealth ram setup. But like RB said, if you already have it and it works, run with it. You can always modify it later for high performance.
I'm not a huge fan of "tuned port" either, the long runner length tends to make it very torquey at low rpm, and fall flat about 3500 rpm. You can counter that by running a non-tuned port intake such as the one I am making, or running something like the LT1 intake or stealth ram setup. But like RB said, if you already have it and it works, run with it. You can always modify it later for high performance.
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