87 L98 in a 91 Firebird Convertible

Stock Throttle Body
Ported Plenum
Ported SLP Runners
Edelbrock 3860 Base
Stock Heads, cleaned, new springs and retainers, valve stem seals
Stock Rockers
Crane 2032 cam
Stock bottom end fully rebuit

1 5/8 Shorty Headers
3" cat back

Rebuilt trans
2100 Stall Converter

3.73 Limited slip

stock 15x7 wheels - that will change at some point to 16x8 WS6 wheels. I just like that style on these cars...



So what you think? Thats whats gonna be done by spring, cant wait to get it to the track in April.

Im shooting for Low 13's

 

Aluminium heads (AFR?)

 

very high 13's

 

high 13s is my guess aswell depending on launch control.I think some more stall would be nice and better heads,more aggressive tune might be in order to get you in the mid 13s.Skiftkit and sticky tire will really knock the time down.

 

As you know, convertible are heavier than hard top/coupe model...
My car did a 14.10 don't remember the miles tho with a 5.7 with a mild compcams,
ported L98 heads, 3:42, 1 5/8 headers with a 3'' Dynomax catback, ported stock manifold throttle body and plenum with SLP runners, B&M tranny with 2200 Stall. Back then in 99. After, I added ported edelbrock 60859 heads,SLP 1 3/4 headers, SLP catback, hotcam, a 3:73 and a lot of tuning for a better 13.20 in my 91 convertible...If it can give you an idea

 

Sorry...I had the Vette manifolds bolted to the engine and not the 1 5/8 headers
as mentionned when I did 14.10 on the 1/4 mile...

 

High 13s like 13.92 take some w8 off yer car get it down 2 3400lbs good rubber tune get a tune there is no real mod u can do that don't need a tune yes even headers need a tune even taking the ac and smog off port the heads too

 

13.70-13.80

 

No reason it shouldnt go mid lower 13's with those mods if well tuned and you have 100% traction. Bolt on TPI L98's go 13.5's alll day long. Heck my stock TPI motor did 13.63 with just exhaust and 2800 stall/3.42 gear/slicks. My buddy's bolt on long tube runner TPI L98 did 13.5's on street tires with NO converter and 3.70 gears! Slicks/converter would put him at 13.3's easily

I went 12.95 with HSR intake swap and drag wheels which shaved 70 lbs off the car. This was in optimal air conditions, 188 ft DA which is practically sealevel. Thats some good air considering it was 1200 ft altitude.

You have a mild cam which only adds more power so you should be quicker. stall speed could be increased to 2800 or so but still should crack a high 1.7 60 foot on 2100 + those gears on a good tire.

Buy a set of DOT slicks or good drag radials for the track

 

wont a higher stall like that make it a little of a pain on everyday normal street driving?

 

Not really. I never had a problem. I daily drive a 99 trans am with 3200 stall and daily drove my 89 with bolt ons with the 2800. Once it locks up, it drives no different than stock on highway. Around town at slow speeds is when its open and slipping abit but you just have to adjust to the higher rpms when pulling out from a stop.

I had 3600 in my 383 car and felt like i should had more. The turbo car had 5400 and drove fine but it was really like a 3000 stall when normally driving.

If you havent really driven a high stall car, then I can see the reason for the concern but its really not bad at all. I find it makes normal driving easier and definately more fun