On a mostly stock L98 (SLP headers and Borla exhaust) how much can I expect to gain from porting my plenum, will I notice the difference.

Also,
How much HP should I expect from an L98 with ported plenum, airfoil, SLP 1 3/4" headers, Borla 3" adjustable cat back, Jet Stage 2 Chip, and mabye the SLP cold air kit,,,anyone estimate 1/4 mile times?

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Fire fighting, Scuba Diving, and Fast cars.....Does life get any more exciting

'86 TPi T/A L98

Stuff on Order:
Ram Air Hood
4th gen Spoiler
Borla exhaust
Sub Frame Connectors
STB
and a bunch of other stuff

Q?-Does Prowler orange sound like it will look good on my T/A?

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[This message has been edited by 86FyrBrd (edited July 13, 2001).]

 

You will notice a difference. I guess the mod drops ET by around a tenth or two, but that's a guess. Pulls alot harder over 4000. Best done with some new runners, then you'll really notice the difference.

 

In an issue of Hot Rod(Aug88)The SLP package-runners,cold air,headers,catback and chip,dropped ET and added MPH on an 88 350 F-body with 2.77 gears from 14.9@93 to 14.0@99.Tune it,add the runners,port plenum,adjust fuel pressure,bypass t-body coolant,and you should be able to do near the same.



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1990 Trans Am GTA,Black/Black Leather,350,auto 3.23,Dual Cats,
SLP Package,Fastchip,GSC's,Brand New Trans with Corvette 2400 stall,Servo/Shift Kit
G-tech 1/4mile(before trans and roasting 1st)13.6@104,now probably 13.2@track with traction/good conditions
stock(track)14.3@96
member www.transamgta.com
Previous Thirdgen
1986 Camaro IROC-Z

 

If you have 3.27 gears you may see 13's

I did with minimal mods.


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Mike L.
It ain't pretty.......

1987 IROC Z TPI 350 A4 3.27 Borg-Warner.

Mods: 2300-2500 Stall Converter, Shift Kit(GM parts), TPI Specialties Stage 3 PROM, Modified Airbox w/ K&N's, homemade cold air, Relocated MAT sensor, Gutted MAF, 160* thermostat, Accel 8mm Wires, bypassed TB coolant, Flowmaster 3 chamber single 3" in/out muffler, 3" MAC mandrel intermediate, custom dual !cat Y-pipe. airfoil, ported plenum. !smog

http://www.MichaelLasiuta.home.att.net

**BOYCOTT LAPEER DRAGWAY**

 

The TPI base is just as much a restriction as the Plenum, so if your going to do one, go ahead and do the other. Its great that you have the runners already, but once you do the plenum, the base becomes the bottle neck. Check this out if you want to do the base also: TPI base porting

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'87 Trans Am
S/D TPI retrofit including functional PassKey,
22# injectors,
Whatever chip I feel like burning,
JET AFPR, Ported Plenum,
TB Coolant Bypass, Custom Cold Air,
SSM SFC, KYB Shocks, Boxed LCAs, Wonder Bar,
8mm Accel wires,
Flowmaster Exhaust,
16" GTA rims,
Corvette Servo,
3.73 Posi
4wheel Disc Brakes
Summit 1-5/8" headers, 2.5" Dynomax catback.

Best 1/8: 9.519@72.74

'97 Bonneville SSE