majestyk

I want to make my lt1 caprice a lt4 tips?

Dwayne J

My tip would be don't
Why do you want an LT4?
What are you trying to accomplish?

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Dwayne
96 Caprice with AI 200cc package
Best et 11.5
Best MPH 116
Just another taxi

majestyk

I like the performance the vette had right out the box , I was hopeing it would be cheaper than other mods
And thought it would be badass

Dwayne J

For the same money you can have more power without compromise by using ported LT1 stuff and a modern cam. With lumpy cams there are stock shortblock cars making as much power at the wheels as the full LT4 HOT package does at the flywheel.

I assume where you are inspection is a concern.

This is what I use.
Advanced Induction - 200cc LT1 Competition Head Package

For an emissions setup on a car that won't see much track time you could skip the intake manifold porting just use a stocker, a milder cam, some shorty headers and I would think 360 or so rwhp is still possible where the LT4 package might get you 330 with more compromised lowend. The LT4 stuff really isn't all that great, even ported stuff on racecars the LT1 stuff on average does better with less rpm. Even their 190cc head would do fine for most emissions setups, my car ran 11.9 with those heads a little milder cam/stall/gears.

The ONLY reason I see for the LT4 package is to use all GM stuff on a showcar or something, otherwise there is no point to it. Such opinions upset folks and when I start providing links and car details that support my opinion they get even more upset.

The LT4 HOT package makes 425flywheel HP in a perfect world without accessories and such. Losses from accessories,intake tract, exhaust system etc. to the tires will drag this down near 330rwhp.
Here is what a car with the setup I have makes.
Ai 200cc CNC H/C Dyno, A4, 425rwhp - LS1TECH
The cam is not emissions compatible and needs enough rpm that most wont want to risk it on a stock shortblock.
I don't have dyno info for my car but this is the same setup but in a more track prepped car, few hundred pounds lighter, more stall and gear, no exhaust system and a highly skilled owner who gets every last bit of performance out of it.

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Dwayne
96 Caprice with AI 200cc package
Best et 11.5
Best MPH 116
Just another taxi

ekm1190

that seems like an excellent package for the price, i'd consider buying it if i had the $$$ on me. That dyno he mentioned GM stock manifolds, which I found fairly impressive since i heard that the stock manifolds compared to longtube headers is a fairly large difference (just what i've heard though).

For future reference, i've always wanted a boosted car, in the form of a procharger. Have you heard anything about how well this package will take boost? They have a dyno chart with someone who had ~700 rwhp on boost but i wanted your opinion on it as well. I'm mainly questioning it's durability, as this would be a car i'm keeping.

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majestyk

I want a street car that'll get decent mpg and still be fast . Your heads cost more than im in my car .
Only paid 650 for the car , I put leather in ,z28 cluster ,52mm tb, and all impala badges. And im in around 1500.

ekm1190

stock they are pretty fast already.. if you want it faster i would change your rear end gear ratio, get a good torque converter, and maybe a cheap intake + exhaust. However, the gear ratio will not help your MPG's, but the rest shouldn't hurt.

Dwayne, correct me if i'm wrong (still new to this)

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Dwayne J

http://www.impalaforums.com/chevy-im...tml#post269706

Far as cost, yeah performance is pricey, LT4 setup would cost at least as much because they need an LT4 intake to seal to the taller ports in the heads, the GM one is no longer being made and the Edelbrock $500 piece is JUNK, their LT1 piece has been shown to potentially HURT power over stock.

You can add a LOT of performance with CAI, Exhaust, stall and gears and that is probably more suited to you than the LT4 or the package I have and frankly would be needed before you could go into the engine to add HP.

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Dwayne
96 Caprice with AI 200cc package
Best et 11.5
Best MPH 116
Just another taxi

majestyk

i am building a rasis cai someone on here sent me the measurements , i believe you told me that stock exhuast manifolds work and flow as good as headers . and im going with a 3" exhaust from the manifolds back . when i start my tranny class i will start buying stall and toughen up the tranny . i have a 1.6 roller set up , just didnt want to rip into it if i chose to go lt4 . also what would be the best gear for mpg and decent et at the track. thanks for the help

Dwayne J

No stock exhaust manifolds are not anywhere near as good as headers and I wouldn't bother with dual 3" unless building a pretty stout stroker.

Far as gears 3.42s are nice for a lot of highway driving but if you don't spend a lot of time at 75mph plus most guys really like 3.73s.

Honestly with my car I still get about 18mpg with mixed rural driving, don't put on a lot of highway miles unless I am going down to GLD to race and then including racing get about 18-19mpg. Given something near twice stock LT1 output, 3800 stall and 4.10s I think that is perfectly acceptable.

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Dwayne
96 Caprice with AI 200cc package
Best et 11.5
Best MPH 116
Just another taxi

ekm1190

Can the stock tranny handle 4.10s and that high of a stall?

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Dwayne J

what about either would be hard on a tranny?
A good 9.5" converter is a lot less weight hanging on the input. The "looser" converter acts as a shock absorber between the engine and tranny.
A Transgo kit is a good idea but then again they are a good idea in a stock vehicle.

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Dwayne
96 Caprice with AI 200cc package
Best et 11.5
Best MPH 116
Just another taxi

ekm1190

I honestly thought the 4.10's would be more stressful on the tranny then the converter, but that's just what i'm picturing in my head... And can you please explain what a Transgo kit does for me?

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Dwayne J

Transgo has shift kits that also address design flaws and compromises GM put into the tranny. It will eliminate things like PWM which pulses clutches on instead of just applying them. GM designed this to hide the feel of things like the torque converter lockup. They wanted the tranny to feel more or less like there were no gear changes or anything. Most of us don't mind feeling a gear change or torque converter lockup and by allowing them to just apply cleanly you reduce wear and heat. When the Pulse Width Modulation pulses it slips the clutch.

Transgo has different levels of kits, they have really cheap basic ones that almost all basic rebuilders use called a "problem solver" which just corrects and improves common failure causes and items and then there are performance shift kits which include the basic kit but do more.

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Dwayne
96 Caprice with AI 200cc package
Best et 11.5
Best MPH 116
Just another taxi

ekm1190

Ok cool i didn't realize that, definitely something to look into then.

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