GASGZLR

I am curious what mods will a 89 TBI 305 auto need to run dead even with a 91 305 TPI auto (205 hp)? My buddy thinks his car is so fast (the 91) and he says he can take me in my 89 TBI. His car is stone stock, I checked, and he is not knowlegeable enough to have it chipped or anything since he just got it and he is like 15.

ShiftyCapone

iTrader: (7)

A full exhaust, open element and a good tune up is about it. Some traction and suspension always helps to. But speaking only power wise you can match his power level with those few mods.

BronYrAur

iTrader: (1)

Yeah I don't think it'll take too much. Two of my buddies have 305 TPI cars and I was racing them on the highway and held right next to them the whole time and all I had at the time was open element and a flowmaster muffler. My car's a 5 speed though. Now with 3.42's, posi, and a little advanced timing I think I could take both of them.

Dennis91RS

yeah tpi isnt all that dude

if i had a choice id go with the LO3 rather than the LB9

biggest reason is its cheaper

Fast305

In my opinon you need an open air cleaner, exhaust, custom chip, 350 injectors, a good tune-up, and maybe a 2,000-2,500 rpm stall or a gear change. If you choose headers use ones meant for a 350 tpi as they will fit the 305 but use larger tubes.
In a camaro I would take a tbi over the tpi anyday. Because the tbi is much cheaper to mod than the tpi is. The tpi is the best "Truck" motor that chevy ever built. They come on strong real low then die over 4,000 rpm. I am thinking about using a dead stock tpi intake with the megasquirt on my tow vehcile though.

ShiftyCapone

iTrader: (7)

Good points but you do NOT need 350 inejctors or a custom chip. Custom chips can improve the performance of a stock TBI car but only if you burn them yourslef. Also, 350 injectors will only cause problems unless you are pushing 300 at the crank. The stockers will go quite far. You will need an exhaust hands down to keep up with a 305 TPI car.

90RS305

One of the members on the board (not saying any names ) has an LB9 (305 TPI) and I have the LO3 with nothing more than an open element and flowmaster 40 series... We went down to the dragstrip the other day and I beat him 4 - 0. The closest he came to beating me was when I had a 200lbs+ passenger and I still took him by .02 seconds. Granted the manual cars came with 3.08's instead of 2.73's, but thats beside the point! I love my 305 TBI, it really does not take a whole lot to wake these engines up!!

Bruce (90RS305)

GASGZLR

I have a B&M Tork master 2000 converter, stage 2 shift kit, Corvette servo, Jet stage 1 chip, K&N filter in the stock air housing thing, a flowmaster 80 series muffler, and 6* adavnced timing with a perfect tune. All else is stock, 2.73's, one wheel peel, NO ultimate TBI mods. Do I have a chance?

ShiftyCapone

iTrader: (7)

Yea you should fare quite well.

DuronClocker

iTrader: (1)

Doing the ultimate TBI mods wouldn't hurt, and from what I can tell they seem to be easy to do. Hopefully, I'll have some first-hand experience with this within a week or two

IROCaholic

Since the car is auto I dont think you need much,I would upgrade those 2.73's for sure, but werent the 91 305 tpi's one of the better years. All I know is all the stock auto LB9's Ive seen have run about the same times as a stock L03's depending on gears. Now if you were running agaist a 5 spd I would have to give it to him . My brothers 305 5spd ran low 15's stone stock with 3.23's and I have seen alot of L03's with all of your basic bolt ons have trouble running those times. So it really depends if he has a peanut cam rear or not. Good Luck.

Dewey316

did anyone forget to bring up what exactly the other car is?

if it is a 5speed, G92 optioned 90-92 TPI car, you have a bit more work involved, i have seen several of them dyno 220+ to the wheels. and run mid-low 14's consistantly.

if it is an auto, or a non g92 car, it won't take much, stock , with nothing more than tuning, i have timeslips that beat most TPI cars, with headers, i run with L98 cars, and with the cam in the car, i have can take a LT1.

Gunny Highway

iTrader: (1)

Open element

3.23 or lower gears

full exhuast

advanced timing

a good tune up

With these you will leave him in the dust. I can't stress enough how bad the 2.73 gears are or how pathetic our stock exhaust is. To this day, I don't know what those jackasses at GM were thinking.

90RS305

They were thinking "Hmm...cheaper to do it this way and then they'll come back because they want more...

Bruce (90RS305)

DM91RS

If Gm was thinking? LOL!l

let's see:

Hey Bob! You think we could use the same heads on both our 305 engines we use on our F-body's?

Bob: Yeah that would probably save money but Jack Meoff over in casting R&D has an idea on something called swirl port heads. Maybe he just needs something to do I don't know but let's give him a call. OK?

DM91RS

Oh Yeah......Welcome home Gunny! Good to be back in G0d's county?

del91_305

My buddy used to have a LB9 in a GTA and i have a LO3 that at the time had nothing but open element and catback exhaust and i could kill him everytime down the strip, then on the street i could usually beat him off the line. But it was funny because from inside his car it felt a whole lot quicker than mine, but i was able to beat him.

Fast305

The swirl ports were already in use on the chevy trucks and vans as well as caprice. You could find the swirl ports on some 1987 carbed applications. Has anyone ever noticed what happens to gas mileage when they are dumped??? It goes down atleast 10%.