L98 preformance
Team Owner
Joined: Oct 2004
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From: altered state
St. Jude Donor '05
Cost?? With a name like Colonwasher Id be worried about the hours and conditions youd have to work with . 
J/K....Seriously, 350 is achieveable depends how good you are with a wrench.
J/K....Seriously, 350 is achieveable depends how good you are with a wrench.
Le Mans Master
Joined: Jun 2006
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From: One day you're a Comet...the next day you're dust... Arkansas
Race Director
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From: Database Error Indiana
Racer
Joined: Dec 2004
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i believe the stock L98 heads will are good for 350 fw/hp. (porting would be a good idea), also a good exhaust IE headers, gutted cat (or a better flowing) and as said cam and intake (if you can get a hold of a super ram try that). maybe #24 injectors, and a pcm tune. that should get you fairly close
Burning Brakes
Joined: Aug 2005
Posts: 1,172
Likes: 9
From: '88 TPI L98/HotCam Powell, Ohio
Headers, X-pipe and true duals will get you close to 300hp* for ~ $1200. (My L98 was 250 rwhp / 330 rwtq at that point)
Cam / Heads (aftermarket or CNC your 113's) + intake work will get you over 350hp*. ~ $2500. If you do the labor.
* Not RWHP
Cam / Heads (aftermarket or CNC your 113's) + intake work will get you over 350hp*. ~ $2500. If you do the labor.
* Not RWHP
Racer
Joined: Mar 2002
Posts: 405
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From: Franklinville, NJ & Deerfield Beach, FL
If installation is done correctly and you use quality parts when replacing the internals of the engine (heads, cam, etc) hurt overall reliability?
Race Director
Joined: Sep 2003
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From: Database Error Indiana
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From: Pittsburgh PA
Le Mans Master
Joined: Mar 2004
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From: Dublin CA
You can get about 350 at the crank without too much trouble or machine work.
You don't tell us what year your car is.
My car is a 85 with the bottom end still stock (stock cam and pistons). I am running close to 350 at the crank with the mods listed below and a test pipe instead of the cat. I use this set up for the track.
So if you add AFT 180 heads, 1.6 and 1.5 roller rockers, SuperRam and do some exhaust pipe work it can be done. Add a cam (will have to rework the chip) and you will be over 350 HP.
You don't tell us what year your car is.
My car is a 85 with the bottom end still stock (stock cam and pistons). I am running close to 350 at the crank with the mods listed below and a test pipe instead of the cat. I use this set up for the track.
So if you add AFT 180 heads, 1.6 and 1.5 roller rockers, SuperRam and do some exhaust pipe work it can be done. Add a cam (will have to rework the chip) and you will be over 350 HP.
Thread Starter
Intermediate
Joined: Jan 2008
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From: El Toro California
Thread Starter
Intermediate
Joined: Jan 2008
Posts: 25
Likes: 0
From: El Toro California
also how much engine speed is a stock L98 bottom end good for
i got an 85 and im pretty ok with a wrench.
im not gonna be a Jerk and say im wonderful.
and for a couple of grand isent it easyer to do an Ltx swap?
i got an 85 and im pretty ok with a wrench.
im not gonna be a Jerk and say im wonderful.
and for a couple of grand isent it easyer to do an Ltx swap?
Team Owner
Joined: Feb 2006
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From: sw Ohio
Here's what i've done to mine and its probably got 300 HP with the stock TPI. You could probably add a Holley Stealth Ram and some good computer tuning to get around your goal. The HSR is like roughly $350.
Heads $1300
Cam Free!
Exhaust $1000
Fuel upgrade $250
BTW: Going from L98 to LTX is a big waste of money. Theres not that much of a difference to justify all that labor. If your gonna swap motors go with a LSX and your already at 350 HP.
Heads $1300
Cam Free!
Exhaust $1000
Fuel upgrade $250
BTW: Going from L98 to LTX is a big waste of money. Theres not that much of a difference to justify all that labor. If your gonna swap motors go with a LSX and your already at 350 HP.
Race Director
Joined: Jan 2008
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From: oregon
porting the TPI, that's smoothing the TB, doing the plenum, sandblasting the EGR crap out of the runners and matching them. enlarging the base runners and straightening the turns. Using a good long tube, 1.5RR's if you don't change springs, 1.6's if you buy the cheap but quite good LT4 springs. True dual and a 160 thermostat coupled with a TPIS foam or K&N, cut air lid and some of the other free mods i forgot will get a 90-91 car in the low 13s on street tires. My old 91 did a 13.2 with the above mentioned. L98's are affordable to mod up to this point. beyond this you start building bottom ends to take more RPM, buying better heads, getting a SR or MR and doing some tuning. I now have a 1990 car that runs 12.3s and put down 352 or 358 RWHP depending on which dyno day, has a perfectly flat torque curve peaking right about the same number as the HP and would cost stupid amounts of money to re create. Stupid at least from my point of view. You would spend around $8000 to duplicate the setup. These retarded Minirams cost as much as a winter beater car. The receipt i have on the heads is over $2000, there's $3500 on heads and intake. If you have that kind of money to just toss, unload the C4, buy a 2001 or newer c5 and spend less to go faster.
Burning Brakes
Joined: Aug 2005
Posts: 1,172
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From: '88 TPI L98/HotCam Powell, Ohio
1) Headers and exhaust will give you more power than an LT1.
2) The other mods will get you close to C5 Z06 power.
All without pulling the motor. (Stock bottom end)
Thread Starter
Intermediate
Joined: Jan 2008
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From: El Toro California
L98
How much Rpm can the standard bottom end stand?
just for a safety point of view
i dont want to go putting a high rpm cam set up in it and find out that
the stock wrist pins have a hard time with 6 to 6500 cause you honestly dont need more than that.
Do you have any must have mods you reccomend?
Team Owner
Joined: Oct 2004
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From: altered state
St. Jude Donor '05
Colin, I hope you know i was yanking our chain a lil 
6k is probably safe for the L98s but wouldnt twist it up real high on a normal basis (6500). You could get a better crank kit pretty cheap these days unless you really plan on twisting the motor.
6k is probably safe for the L98s but wouldnt twist it up real high on a normal basis (6500). You could get a better crank kit pretty cheap these days unless you really plan on twisting the motor.