insomniac

iTrader: (3)

Anyone get into the 12's on the stock L98 heads? No boost or nitrous...

GTA Sammy

iTrader: (1)

It all depends on who you talk too...

insomniac

iTrader: (3)

what u mean? only if someone is full of ****?

Marv02

I would think it will be cheeper and much easyer to buy a good set of after market heads that you know going to do what you want to do.

Just think have the heads machined for larger valves and have them ported bench flow tested to see if they will even flow enough to work even if the do or dont and if they dont I sure they still going to stick you for the bill for there Labor time Bench flow time and parts.

GTA Sammy

iTrader: (1)

Well, there is the odd know it all kid that will sling Sh*t around here... (With their 12 second 305's... That will beat your car all day long blah, blah, blah, cough,cough)
Thank God that it's rare and they often get themselves banned...

Well, I'm no "ASE Certified, Degree Holding Technician..." but....

To run 12's your gonna have to get outta the hole very well with a great launch ie Stall, Shift Kit and Drag Radials... maybe gears...
I would think most people would agree that you'd have to run an Aftermarket Intake... something to extend the usable RPM...
Moderate to Higher Duration Camshaft >230* with valve springs to handle it
Free flowing Exhaust, Port work
and the almighty ECM Prom Tuning

Now some cars run better than others, there's no question about that... Mine seems to be the slower...

There are members who have flowed the L98 heads... with surprising results... but the rest of the parts have to complement the whole...

TTOP350

iTrader: (8)

Marv02

Just trying to save him some money instead sinking all kinds of money in to a set of L98 heads when he could purchase a set of after market proven heads for the same or less money with lot less problems.

I hate for Him to dump all kinds of his or hers hard earned money in to a set of stock heads just to end up getting rid of them and now go out and buy a set of After Market heads now there out a lot cash.

Or you guy like Pimp my ride dump bunch of cash in a POS it mite look good on the outside in your eyes but it still a POS in the end.

Orr89RocZ

iTrader: (20)

12's on stock heads is easy

I did 12.95 with just bolt ons only....stock cam! Its not that hard if the car isnt a pig and you run in good air conditions. (ie sealevel type)

3.42's, 2800 stall, slicks/skinnies 3450lb with me in it. Full suspension, stealth ram intake, headers/exhaust.

Stock 150k mile L98 longblock. stock heads/stock cam but with 1.6 ratio roller tip rockers.

Cam only / intake type build should go deep into the 12's

Stock heads can support more than enough hp to run 12's. I'd venture to say a better question is, can they do 11's? I think it could be possible in the right chassis. You only need 330whp to do so

Marv02

If you want to learn more about heads take a look at grumpy's Forum:

http://forum.grumpysperformance.com/...php?f=52&t=796

GTA Sammy

iTrader: (1)

No disrespect to you Marv02....
2 totally different conversations....
Trust me Nobody's bashing you...

The original poster was talking about L98 heads...
Some members have made them flow real well...
https://www.thirdgen.org/forums/tpi/...d-project.html

Post 42
https://www.thirdgen.org/forums/tbi/...ted-193-s.html

I agree with you though!!!! I wouldn't waste $$$ trying to make 083 heads strong performers.
I bought AFR's years ago.... Wouldn't look back!!!
But you gotta admit, the rest of the car still has to be upgraded to run 12's.

BuzzLOL

.. I see you have a 305" TBI... by "L98 heads" I hope you mean the heads found on a TPI 350" engine... these are good for about 380-390 grossHP on the 350" engine with everything else optimised and a bit more cam like a modern 214/224... they would lose compression on a 305" engine unless mini-dome pistons were swapped in... this is enough power to make high 12's with good traction, headers, bigger y-pipe, dual cats or no cats, 3" or larger exhaust system/muffler, free flowing air cleaner assembly... possibly some siamesing of intake runners and ECM/chip tuning... skim through the 'Performance Prom' 'sticky' above if haven't already read it...

insomniac

iTrader: (3)

Yes did mean on a L98. Im in the process of a complete transformation of my 91 Vert.

I am about 3/4 of the way done with the motor from a 87 Iroc here are some pics: http://gardengrasp.com/firebird/transformation.htm

The car will be a street car 99% of the time. Basically when im done this is what ill have. I wonder what kind of HP and ET this will run. Im also pretty sure the verts are heavier any idea how much they way?

Motor:
87 L98
Completely rebuilt
Heads - valve job, cleaned, valve stem seals, manly springs and retainers.
Crane Cam 2032
TPIS Big Mouth Inatke Base
Ported SLP Runners
Ported Plenum
Stock TB - Air Foil
MSD 8366 Distributor

Trans:
Complete Rebuild
Minor upgrades
2200 stall


Rear Diff:
3:45 posi 9 bolt
Rear Disc conversion

Exhaust:
Hooker 2044 Headers & Y pipe
3" Walker cat
3" Magnaflow cat back

Suspension:
Alston SFC's
Bilstein rear shocks
KYB front strus
New rear springs
Founder performance panhard bar and rear control arms
Complete streering end to end
16X8 WS6 wheels - Firestone Firehawk Indy 500 tires 245/50/16


Id be thrilled if that can get me in the 12's

but accoriding to this calculator: http://raceprecision.com/1-4%20MileCalculator.htm

I will need 325 rwhp to dip into the 12's, dont know if this setup is gonna get me there. Assuming the vert will weigh about 3600 that is... which i could be off on

Marv02

Good deal I have other gave me bad advice before costing me more money and time than I have so it bothers me when you have other giving out bad info doing so.

I know most of us dont have unlimited bank account funds to waste.

I not Emron tell you to invest you hard earned money in a product that I think you end up lossing you butt doing so.

Orr89RocZ

iTrader: (20)

You dont need quite that much power to get 12's but if you are near 3600 lbs, then more power is always a good thing. My 99 TA is likely near 3500-3600 with me in it. 330-ish whp, 12.2's at 110. My friends L98 car made 330whp and he ran 12.2's in warm air at 3450-ish lbs. So you definately will be deep into the 12's with near 300whp.

That combo on stock heads may get near 280-300whp. Thats enough to run 12's. I'd run abit more converter, something like 2600-2800.

You will want a drag radial or slick of some sort. You need mid 1.7 60 foot times to really get into the 12's with that power, so traction is key.

insomniac

iTrader: (3)

how is 2600-2800 stall gonna be for regular street driving though?

TTOP350

iTrader: (8)

Just fine.

Orr89RocZ

iTrader: (20)

^ agreed! dont be afraid of some converter. If you never driven a car with some converter, then you will be surprised at first...but then you get used to it and before long, its like stock I daily drove 2800 on my L98 for 2 years... best mod for the money I ever bought. I daily drive 3200 in my 99 Trans am. I wish I had gone 3800-4000.

When you come off the line, it does take abit more throttle input, and the converter will slip some rpms before the car gets moving...but you just have to adjust your driving style alittle when pulling out from a stop. My first time, I lit the tires up just about every time when quickly trying to pull out from a stop, since I was so used to driving stock converter and 2.77 gears. The converter will flash up 2000-2200 rpms with mild throttle stabs that normally would make a stock converter car pull out kinda slowly. The converter is making engine speeds higher where there is much more power/tq available and it multiplies that power to the tires. Its really easy to get used to tho.


During normal cruise, the converter locks up so there is no slip. It drives exactly like stock at that point. You can tune the MPH you want it to lock at as well in the chip. Or put it on a switch but its alot easier to just keep it on the chip so you never forget to unlock it. You can have 5000 rpm stall speed lockup like stock and you'd never know til you went WOT.

2800 or so is great for TPI...i'd even go as high as 3200 with siamesed runner setups or really well ported big tube setups with enough cam. The 60 ft is where alot of ET comes from, so the better you can do there, the better the end results will be. TPI makes a bunch of low end power, so use it to get off the line and thru the first 330 ft as best you can.

gp90gta

iTrader: (1)

I have a cheap $300 Revmax converter thats a 3200 stall, and though its a little loose, its not bad at all, a more highend one would be better but since I figured why spend a $1000 for a good one when my trans most likely wont hold much longer anyway.

insomniac

iTrader: (3)

got ya. thanks. does the slip hurt the trans overtime?

Orr89RocZ

iTrader: (20)

Shouldnt skip out on a quality converter...I had a buddy use Revmax and it came apart on him. A good midrange quality converter is something like Edge Racing or Midwest converters, maybe Circle D's street converter that goes up to 2600, some others out there.... anything 450-550 or so is a starting point. They arent the cheapest mod, but really make a huge difference in how a car leaves and transfers power.

Too much slipping over a long period of time can over heat the fluid in the trans...thats why you should use a trans cooler if not already using one. My 89 Camaro had one stock built into the rad so I used that just fine. 2800 Edge racing, never had an issue. Had Edge restall that to 3600 on the 383 and never had an issue. 3200 Edge in my trans am, bought used second hand from another guy. Still working great. With a cooler, it should be fine, but as long as you keep it locked up during cruise or regular driving, you will be fine.

insomniac

iTrader: (3)

well its not gonna lock up til like 45-55mph correct?

BuzzLOL

.. You can tune that into the ECM/chip... otherwise it stays at the stock MPH...

GTA matt

iTrader: (1)

I'm not gonna quote the OP's mods all over again, but thats a decent list. Those should put you into the 12's even in the heavier vert. As said before, don't fear the stall, but be sure to get a decent tranny cooler. Although much debated, I went a 12.85 a few years ago with bolt ons only, stock intake base, runners and heads. A big mouth base and slp runners and a cam would have been good for a few tenths, and a miniram I'm sure would've put it mid 12's with the stock heads.