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

85 tpi 3+4....

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Old Oct 11, 2018 | 05:53 PM
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Default 85 tpi 3+4....

Hello folks I haven't done anything major to the l89 because I'll be getting a c5 or sti in November.........but I feel as if I have push the c4 as far as she will go.....keep in mind this car was not running when I got it......now I'm just about done doing basic things to bring it back to life from it's 15 year nap I took.....I want to gain 50 to 60 hp with out doing a complete swap or boar I'm looking to spend around 600 maybe ..........I was wanting to do a lt1 intake...cam... different heads...and long tube headers......

****what would I need to do to fit a lt1 intake on a l89??

****What heads should I go for....or should I just do rockers and springs???

Short of a nos kit am I missing something else I can do to gain some hp???
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Old Oct 17, 2018 | 11:54 AM
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What do I n​​​​​eed to do to mount a lt1 intake on a l89
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Old Oct 17, 2018 | 12:00 PM
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$600.00......

very small budget....a GOOD set of headers will cost that much or more......

50 hp difference needs a bigger budget.
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Old Oct 17, 2018 | 12:02 PM
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Well over any thin grand......I may as well put a downpdown payment on c5 right
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Old Oct 18, 2018 | 07:09 AM
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Pretty much....these days...

the prices of C5’s are heading south like the C4. Ten or fifteen years ago, Different story.
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Old Oct 18, 2018 | 10:49 AM
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A used nitrous kit will fit your budget.
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Old Oct 18, 2018 | 12:27 PM
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I think you mean L98.

Swapping the intake is going to require welding and machine work. It will allow the RPM range to shift and make more upper HP but trade off peak and average torque. It will make the car faster but won't be cheap.

$600 is not enough money to make real gains. I am with the used Nitrous kit.

Other suggestion is gear. What gear do you have? The TPI will like a 3.54 gear A LOT.

If you put a more realistic budget to it and want gains
A TPI loves headers/exhaust. The manifolds on them were crap.
Gear if you don't already have the lower gear option.
AFPR, the TPIs run rich
a Small bump of base timing and run premium fuel
Port match the Intake/Runners/Base.... get more air and maybe a few RPM

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Old Oct 20, 2018 | 10:35 AM
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Originally Posted by KyleF
I think you mean L98.

Swapping the intake is going to require welding and machine work. It will allow the RPM range to shift and make more upper HP but trade off peak and average torque. It will make the car faster but won't be cheap.

$600 is not enough money to make real gains. I am with the used Nitrous kit.

Other suggestion is gear. What gear do you have? The TPI will like a 3.54 gear A LOT.

If you put a more realistic budget to it and want gains
A TPI loves headers/exhaust. The manifolds on them were crap.
Gear if you don't already have the lower gear option.
AFPR, the TPIs run rich
a Small bump of base timing and run premium fuel
Port match the Intake/Runners/Base.... get more air and maybe a few RPM

Ok everyone just keeps saying intake swap it and not a way to do it !
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Old Oct 22, 2018 | 11:06 AM
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Originally Posted by KyleF
Swapping the intake is going to require welding and machine work.
For an LT1... the factory ones do not have a distributor hole and the intake mounting bolts to the heads will not line up. I don't have the specifics as I have never done this swap, but there are other options out there made for TPI that will bolt right on. Have to be careful of hood clearance as well. They are pricier than just a factory LT1, but will bolt right on. Just have to watch the boards and ebay and try to catch a deal.
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Old Oct 24, 2018 | 11:21 PM
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https://www.eecis.udel.edu/~davis/z2...ke_conversion/

Currently headed down this route. I had access to a machine shop in college where I milled the casting flat in the back and CNC'd a distributor spacer after measurements. It's been a long process yet to be proven. A mini ram is probably a better path except all of this has been no cost to me so far.
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Old Oct 26, 2018 | 08:19 AM
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With your limited budget it's what you're can DIY and a little luck in finding inexpensive used parts. Headers and exhaust ( used LT1 low cost option). LT1 sbc intakes show up for sale but usually over 500. DIY Match porting and larger runners will fit your budget.
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