C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

L83 Questions

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Old Feb 7, 2008 | 09:44 PM
  #1  
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Hello, I have an 84 CFI c4, now I want to get the most I can out of this car. The engine IS a 350ci engine... so is this possible to build a 383 stroker out of it? And can I switch my CFI to a TPI from a junked vette? Is this all pointless, should I just sell it and buy a later year? I figure I can't just trade it as it is worth a little less than a later year. Idk, can anyone update me on this?
Thanks guys.
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Old Feb 8, 2008 | 12:51 AM
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No reason why not to go to 383.. but you will leave a lot on the table if you use the CFI or TPI.. Don't know too much about the CFI.. but the stock TPI will run out of air around 4500-5000 RPM.. you will need to go to a Mini Ram or Ported TPI or Super Ram.

Are you worried about Smog laws ?

Might be cheaper to sell and upgrade...
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Old Feb 8, 2008 | 07:53 AM
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Originally Posted by Schecter
Hello, I have an 84 CFI c4, now I want to get the most I can out of this car. The engine IS a 350ci engine... so is this possible to build a 383 stroker out of it? And can I switch my CFI to a TPI from a junked vette? Is this all pointless, should I just sell it and buy a later year? I figure I can't just trade it as it is worth a little less than a later year. Idk, can anyone update me on this?
Thanks guys.
Contact CFI-EFI. He's a expert when it comes to building '84 CFI vettes to go 13's! He will probably tell you to refer to the FSM first, but after you've read it from cover to cover he will probably help by making some suggestions that will put you just a hair slower than a stock LT1 car.

Your real answer is going to come down to your budget and goals. I'm not sure how much I'd invest in an '84 car, but then again if the body and interior is mint it's probably worth it.

-- Joe
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Old Feb 8, 2008 | 08:08 AM
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Switching it to a TPI is pointless. The cost/hassle do not outweigh the benefits. You can make a CFI car into a very good driver with plenty of power without breaking the bank. CFI will tell ya, and you should also check out this site:

http://crossfire.home-ip.net

Personally I wouldn't go 383 unless you really want to or the motor needs rebuilding. For a few hundred bucks and some time the stock CFI motor can be made to perform quite well. Port the intake, change the fuel pump to steady the pressure, rebuild the TBs (depending on how many miels are on them), change the exhaust, 1.6 rockers, and gears. Maybe $1k at the most in those mods, and it'll be faster than a stock TPI vette (flame suit on for that one).
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Old Feb 9, 2008 | 01:05 AM
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The runners/ports on an L83 intake are very small diameter limiting air flow. A 383 will be choked and converting to TPI is costly with modest gains at best.
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Old Feb 9, 2008 | 01:30 AM
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Originally Posted by JLeatherman
Maybe $1k at the most in those mods, and it'll be faster than a stock TPI vette (flame suit on for that one).
As many threads as we've had I think you are safe without the flame suit.
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Old Feb 9, 2008 | 01:41 AM
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Originally Posted by jhammons01
As many threads as we've had I think you are safe without the flame suit.
why would he need a flame suit??? CFI isnt that much slower than TPI. Exhaust upgrades are amazingly beneficial to either setup. I couldnt believe how much power I gained from long tube headers
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Old Feb 9, 2008 | 09:11 AM
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Definetly check out the crossfire website that Jleatherman suggested. There is a ton of info there for the CFI's.
Also if you do a search here you will find a lot the threads on a CFI to TPI conversion( more of a debate ). Switching to TPI is not a simple thing if you feel that is a must have. There is plenty to do with what you got already, just do some research and you'll see.
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Old Feb 9, 2008 | 02:11 PM
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Originally Posted by JLeatherman
Switching it to a TPI is pointless. The cost/hassle do not outweigh the benefits.

Especially since the benefits are negligible. If you can't satisfy your performance needs with a modified CFI, then you need a different EFI system, but not the restrictive TPI.


Originally Posted by JLeatherman
For a few hundred bucks and some time the stock CFI motor can be made to perform quite well. Port the intake, change the fuel pump to steady the pressure, rebuild the TBs (depending on how many miels are on them), change the exhaust, 1.6 rockers, and gears. Maybe $1k at the most in those mods, and it'll be faster than a stock TPI vette (flame suit on for that one).

Except for the fuel pump. As long as the stock pump can keep up, there is nothing to be gained by more fuel bypassing in the fuel pressure regulator.


Originally Posted by 856SPEED
The runners/ports on an L83 intake are very small diameter limiting air flow. A 383 will be choked and converting to TPI is costly with modest gains at best.
It IS a regular 350 underneath that deliberately choked up manifold and it will stroke to a 383 just as easily as any other. A fully home ported intake manifold will do a decent job of feeding a 383. Tom400CFI slid a truck 400 long block, with a cam and some headers underneath the Crossfire that came on his 305 Firebird, and it ran rather well.

I have about $1300.00 invested in mine, and almost $900.00 of that is the Vigilanti torque converter.

RACE ON!!!
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