I have one hell of a dilemma, I dont know what would be the best to do... im looking to run with modded LT-1's and mabey even LS-1's. should i sell my 305 tbi t-5 car, and buy a tpi car or a carb car to build? should i build the 305? or get a 350cid motor? if you guys had the money how would you make a 91rs run with the modded lt-1's? please give me a set up that would let me do this.

 

You are going to need a 350 or a fully built and tuned 305 with spray. It is not that hard to beat a stock LT1 car with a heads and cam swap with the proper tuning. However, modded LT1's are a different story. It depends on what you mean by modded. I have raced a slightly tuned vortec 305 TBI in my 95 Z and I pulled away quite easily. With the proper tune that car should run neck and neck with me providing I stay stock. LS1's are out of your range. Don't even bother unless you get rid of the 305. My friends 02 SS makes my LT1 look like a chump.

 

what kinda 350 combo would you recomend? would a 383 or 406 make any better numbers? what kinda limitations exist with keeping the tbi?

 

There are limits with the TBI system when you get into high power numbers. Displacment doesn't matter but fueling a high power motor with the right air is your limitation. To really compete with modded LT1's and LS1's you will need to go carb or TPI with an intake swap (stealth ram, miniram, LT1 intake).

 

Or just get a lt1 and then i belive that put you in the lt1 range possibly. haha
I think your better off asking what times you should get because the lt1's just like every other car can run in a WIDE range of times. Even more so in modded ones.

 

most of the LT1's in my car club are running high 11's low 12's and they are street driven.

 

i will put money on this setup running with a modded LT1, infact i will build one in the future, hopefully near. take a stock L98, get a little bit of head work, port and polish, bigger valves, ZZ9x cam, Hooker SuperComps, true 3" duals, Vortech V2-SQ system, bigger injectors, and go large tube runners with work, and port and polish the plenum and base, or buy a stealth or mini ram. if that doesn't beat a mildly modded LT1 you can feel free to come shoot me. with a good tune that is easily capable of 11's with good suspension and nice meat to burn. but thats just what i want.

*EDIT* oh yeah i'd go forged bottom end too, just because it's smarter with a blown application.

 

Does anyone know the times on a stock Lt1???

 

depends on M6 or A4, driver and conditions... but i believe it's somewhere between 13.7-14.3 just a rough estimate... but i believe thats pretty close.

 

here is my two cents...

What kind of money are you going to spend?

I would just scrap the 305 all together and go with a 350 or 383. I just built a 383 and in the process of installing it and getting a good tune on it. I sticking with the TBI just to see what I can do with it. It is really easy to cop out and use a carb. I am hoping with a good tune to have my hp and torque numbers reaching 400 each. We will see what happens.

 

CHP just did a story on a 305TBI in a '92 RS that after a good bit of work was beating a '97 SS with the LT1.

I have a '97 Z28(LT1), '89 Formula(LO3) and a '91 RS(LO3) and I just don't see the 305TBI geting on my LT1(it has had a few minor mods).

 

Do some more chip work and it should be right on par. Board member Chuck!'s vortec TBI with only a LT1 cam can almost hang with my stock 95 with a partial tune. When he has the tune down I bet he beats me.

EDIT: I just say you still have the stock heads and exahust manifolds. Even still, a little more chip tuning will help tremendously.

 

i really dont care what kinda fueling system, i could keep the tbi,drop a carb on, buy a tpi car, put a crate motor in it (nothen crazy, crate 350 or 383). anyways it dont matter.

I guess the real question is if you were gona have a thirdgen that runs with the lt-1's/ in the 12.XX range how would you do it.

I got one vote for a blown L98 with head/exauhst/cam work

 

You wouldn't need a blown motor for that. There are a million ways to run 12's in a 3rd gen. 99.9% of them don't require the use of a 305. Lets just say I am going the LT1 route in my car.

 

I was able to get a 13.9 out of my 94 6 speed z with only a gutted cat and a cutout. So if you are shooting to hang with that, it can easily be accomplished with a 305 ci motor with tbi on top. Hell, I'll be in the 12's with mine soon. There are numerous, I mean numerous ways to go about it, but you just have to figure out which is best for you. I suggest a little more research.

 

if you REALLY want to keep the 305, you could just go with a good cam/heads swap, TPI, and a twin-turbo or s/c setup, and if your piston rings are in good enough shape, you should be able to hang with fast LT1's, if you run more than like 3 lbs. of boost. that's just silliness though. get a 350, or a 383.

 

12's in a 305... I'll believe it when i see it.

 

Already been done plenty of times before. I don't have a digital video camera either so looks like you'll never believe it.

 

Do you really think it will take a switch to tpi and forced induction to run with lt1's? That's rediculous. A good set of heads and a matching cam will get you well past there if you know what you are doing.

 

Let me correct myself...
12's in a NA 305... i'll believe it when i see it

 

It's been done NA before too, although that is not the route I took.

 

what kind of parts are we talking to make the lo3 run 12's N/A?


what do you guys think of my week, but just rebuilt T-5 behind a motor that pushes 12"s i think it would work better as a boat anchor. i may be wrong.

 

A T5 an 12's, look out. You will be lucky to get 3 pases out of it. Anywhoo, 12's on a 305 TBI all motor is about impossible. 25THRS will be doing it with spray but I have yet to see anyone do it NA.

 

Didn't say an L03, I said a 305

 

I was able to get a 13.3 with stickys catback and cai on my lt1... so lt1s can be a nasty street machine... as for ls1s YIKES!! my friends stock one rips me a new one almost all the time, i can stay up with him if i run stickys but good luck