Well guys I'm gettin ready to blow my tax return on my car.. I have a 91 rs with a 350, I was planning on gettin portet tbi unit, an aluminum intake of sorts, set of heads, cam, roller rockers. Now I understand this won't catulpult me there but I guess real question is will I just be wasting money if I keep tbi unit or just carb the car?

TBI... Toilet Bowl Injection

First you have to get fuel into the motor.
Change the fuel pump to at least 40 PSI and the regulator the get a minimum of 20 PSI.

Otherwise you will be hard pressed to make any power.

There are many threads on TBI builds here on third gen .. And yes u could see 12's with a TBI with very carefull planning and well thought out parts choices .. All the parts in an engine NEED TO COMPLIMENT EACHOTHER ... And say u build ur engine and ur in the low 13's add a 100 Shot .. Problem solved ...
Look into the EBL flash for tuning there are crap tons of info here on it as well

Thanks man that's honestly what I was thinkin I just needed some reassurance

Yea man there are ppl makin 400+ hp with a single 7.4L TBI unit and 80# hr injectors and EBL flash for the tuning

Links to any of these people's build threads and/or dyno sheets and/or time slips?

you can do it. i am gonna be in the 13's with my setup here but as my daily driver that is as far as I wanna go right now. faster you go the less street friendly you are unless you're boosting.

There is a guy on here somewhere building a 500hp TBI .. Te ebl is suppossed to be able to handle 30psi of boost so I'd say u could definitely make 12's as long as u can get the fueling right

If you're gonna blow your taxes. Get an $500 lt1 off craiglist or ls1 since you're blowing money.

Like to get this style engine because it keeps the oldschool hotrod feel

SHUT THE F@%$ UP NEWB.....Yes 12's are possible with TBI it just takes a little patience and finesse. With a 350 that can be done fairly easily, it will take a little work with a 305. My 305 was a 13.5 car with half *** ported ZZ4 heads, cam and many other bolts on I did to the car. I believe that if I ported the heads and intake properly and if I kept my 46mm tbi unit ( I sold it like an idiot) and the proper tuning I could've seen high 12's easily

The engine is now out of the car and I'm building a LT based single plane efi car.

Sounds sick and I was thinkin like a vortect intake and heads set up

I've put together several low 12 second and mid 11 second TBI based setups over the years. Current one I'm doing for a surprise for my dad will be a high 12 second full street 90' camaro TBI based setup.

I've been a member of these forums for over 10 years, and I've yet to see it done. Would sure love to see pics/threads/documentation of yours.

EBL definitely opened the door for it to happen. There are a number of people on here with the expertise to make it happen (rbob, dimented24x7, and fast355, to name a few), but to the best of my knowledge, no one has yet put a naturally aspirated TBI with no power adders into the 12s.

Again, in 10+ years on the boards, have yet to see it. We've been debating the 400 hp barrier since I joined, but I'm pretty sure it has yet to be broken.

LOL!!! I can lay down a list of 4 proven combos but after hearing them you will just say "noway is't doing that" or something else so what's the point.
Guys have been getting sbf 302s to make that power and more for years so why can't a 305 run just as hard? It can and I've done it.
I've have been building cars for 24 years (pulled my first motor with pops at 14). I have been grudge racing since 1991 (79' regal, 70' 350 Olds rocket motor with cam, intake and headers back then). Built many motors and combos over the years and had many people doubt some of the things that I've built and tried. One thing that I really don't like about these forums is how people can be if they haven't been able do something that someone else has. In my shop I do a lot of custom and fab work, head and intake porting and so on. I've built true dual exhaust systems that looked like they came from the factory for F-bodies as early as 1991' when people were saying "it couldn't be done".
Yes, I have built NA 11 and 12 second TBI based TBI F-bodies and 11 and 10 second 302 based fox bodies. I have also seen a lot of members on here spend a lot of money on parts and have their cars run slower than some of the cars that I've built with basic well put together combos because they followed the bandwagon.
Their is not much about a car that I can't do or haven't done on over the years (from Bodywork to drivetrain to custom painting to custom tuning).
We grudge race our cars and make money from getting them to look slow but run fast so being creative helps.
It doesn't take a lot of power to run 12s in an F-body just the right combo of parts and good traction.

Ummmmm ..... yeah. There's a HUGE difference between a 5.0 Ford, and an L03; bore size, heads, FI, just to name a few. There is no comparison.

GREAT. I can't wait to see the pics/videos/details of the setups. While 12 second TBIs are debatable, and (at least) VERY rare, none of us has, to the best of my knowledge, been able to get one into the 11s. Please detail the build for us so we can share in your knowledge.

BYW what does "TBI based F-bodies" mean?

Street car, street tires, full interior, mufflers up; gotta have 350+ hp.

Very much so. I own a 91' GT and have it running low 11's on motor with a bolt on stock bottom end 302 and a bunch of ported factory parts. Once you know what's holding a motor back all you have to do is improve on it. The LO3 needs head flow, intake, the right cam, a little more CR, the right spark curve and enuff fuel.



Like I said, I have listed combos on this forum before just to have people say no way or PM me saying Im lying. The combos I speak of are on cars that are running and working. The parts are not black magic, just simple well thought out combos.


TBI injection but aftermarket intake, cam, different or ported heads, bigger TB and larger injectors. Nothing special on that but I have also built hybrid 350 based systems too that made even more power.


On the track, slicks, 3350 lbs, the right gear, right stall, traction, good flowing duals or 4" exhaust with straight thru mufflers don't need 350 rwhp to do it. Been there done that.

Originally Posted by seanof30306: Street car, street tires, full interior, mufflers up; gotta have 350+ hp.

STREET CARS can use DRs or slicks on the track.

I don't own a fast car. used to own a 12.8 ext cab chevy truck on the juice. 5.3. but I have seen 1200hp street driveable cars. there are a slew of high horsepower cars that can run on the street. the hard part is making them tame enough for traffic but a devil on the track. my truck was a 175 shot of juice. STREET IS A BIG WORD. I can drive anything on the street for a short distance. I have and helped put many a racecar together since I am a mechanic. just always had other people that were good pick out the cams and heads for the set ups I wanted.

i built a pretty nasty 383 tbi motor using a 670 holley truck TB and an edelbrock intake/head setup i ported the CRAP out of, but i dont have an exact number. best guess seat of the pants would be 375-ish HP. this was in a '95 silverado tho, have little experience modding 305 TBI cars other than camming my first firebird... anyone ever try the truck TB?

I believe the question was asked 12 second tbi. in the original post there was a mention of a 350. IMO opinion it could be any engine. I know there are 383 tbi and 400 tbi engines. but I don't believe they were built with 12 seconds in mind as realistic. but to me in all honesty it goes back to the same ol thing. HOW MUCH MONEY DO YOU HAVE TO GO FAST. and the next statement! just cause you aint seen it don't mean it has not been done.

absolutely. nitrous would get you there for sure, with some upgrades to the engine (i had around 5k in mine, could be done for less) would definitely need to up your fuel pressure and upgrade injectors. my first setup i tried to build a tbi on i gutted the factory FPR and plumbed an adjustable FPR into the return (didnt like the cruddy little thumb wheel on the adj. fpr's made for tbi's) and put a higher pressure pump in the tank. with good heads, intake work, exhaust and a LOT of tuning you could even potentially set up a blow-thru SC and use a boost-referenced regulator that way and if i remember correctly whipple made a supercharger truck kit that it might be possible to adapt to your car. lots of options out there if you think creatively

OK, this is a TBI combo that I built a while ago that is alive and running.

91' stock bottom 305 tbi motor (9.7 to 1 CR)
Fully Ported tbi swirls milled .020" 1.94/1.5 valves beehive springs
454 TBI with bigger injectors 30 psi at wot
Ported holley tbi manifold
UD pulleys
Comp Cams XFI cam 262 grind retarded 4 degrees
1.5 RR
1 5/8" headers, 2.5" true dual exhaust using two Magnaflow round mufflers
Built 700R4 with 3200 stall converter
EBL tuned by myself
3.73 gear Auburn posi 28 spline axles
Aluminum Driveshaft
90/10 struts and 50/50 shocks
Car weighs about 3400lbs with driver
26" MT and front runners
Car runs 12.40s @ 107 - 108
Drives to and from the track (70 miles round trip)and is a true STREET car
He also drives the car to work on nice days
It is a nice clean build that is fun to drive on the track, nothing crazy

With todays parts and tech their are a lot of fast street cars out there that look like nothing special. My Z28 is one of them (8 second street car) and so is my Mustang (low 11s on motor and still has AC, heat, full interior and exhaust), hell my Tahoe runs 14s lol. It is even easier with power adders. You just have to know what works and what doesn't.
There is a event that goes on several times a year at the local track called Street Car Chaos. Some of the fastest street cars around come there to grudge race for $$$$. You will see a lot of sleepers that don't seem like they should be running the times they are running but they are.

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Well I will be building an LO3 within the next 2 months so ill let y'all know some 1/8 mile time as soon as I get it broke in to give everyone an idea of what can be done .. But keep in mind this will be a 305 .30 over with factory LO3 heads w/ 1.94 valves ported and pushed by myself

Sorry, cowboy gonna have to see that one to believe it.

Sleeps, why would you put money into an L03 when for around 2 grand you can have a brand new L31 shortblock with upgraded Vortecs that will last longer and give you more power than that L03 ever could?

Hey, if you have an L03 in your car that runs, have fun with it and learn .... Look what Dewey316 did with his. But, in my opinion, it is a horribly inefficient use of money to put it into an L03.

Here are the XFI cams Comp lists for roller cam SBCs. It shows no 262 grind. Which of these do you have?

I agree and I'm all about TBI .. But a 305 LO3 W/ stock bottom end runnin 12.40's gotta see it .. If it was a 350 or even a stroked 305 (331-340) I MiGht believe it

Cause all I need is an intake , oil pump , rebuild kit and machine wrk .. Prolly under a grand at this point

I did it with a GM846 cammed 100K mile 305 Vortec in a 1980 Corvette running a big block TBI and a 4L60E with a converter that was flashing nearly 4,000 rpm, shifting at 6,500-6,600. DA was -700 ft and it went 12.48 @ 107 on a 1.7s 60'. That was on drag radials with the stock 3.07 gear. Even with a quadrajet carb, dual plane intake and stock stalled 1.78 low 2spd powerglide the car ran into the 13s and put about 4 lengths from 60 to 90 on my Titan that traps 98 mph in the 1/4!!

Thank you Fast! Some poeple kill me when they can't believe something that they haven't done yet. That's exactly how we take guys money when we grudge race! They all think the same way, and in the end they hand over the cash and look dumbfounded. Building the 305 can and is being done. Yes building a 350 with the same parts will get you more power but what if you already have a working 305 and just want to play with it. It is cheaper to build a working 305 then to go out and buy a 350 either new or a used one that you have to rebuild anyway. If you are not looking for gobs of power then just slap on some good heads, cam and other things and have fun with the 305 jeesh. lol

Boy I would love to have him set you out some cars then run you down and take your money lol. I would get some time slips from him but you wouldn't believe that neither. Maybe I can video the car but then again you would just say it's a 350 car (I'm just messing with you) lol. I said earlier in this thread why I didn't want to get into all this. People who are not doing it will say the same thing you just did.

Timeslips, videos or it didn't happen
at least that's the rules of the net these days.

Sorry the EXACT cam info is lol;

Comp Cams 12-412-8
XR264HR-10
it's on a 112 LSA

I was at work and couldn't remember the exact info off the top of my head. I have used that cam for a few builds because I know what to expect from it for street cars.

OOOOOk I will call him up to see if I get something as far as vids or scan some of his slips for you guys because I'm tired of people saying the same ole things when people talk about playing with this damn motor lol.

I'm not questioning you, just saying, if you want to shut up the haters, you gotta prove it.

What's the old saying? "put up ou shut up"?

You know what you are right and that's what me and my boys do. We just do it on the track for cash to add insult to injury lol. I wish I could do that in this situation but I guess I have to settle huh lol.

That's a 106 lsa centerline, according to comp, and in a carbed 356 with Dart Heads, they show it only made 335 hp.

http://www.compcams.com/Technical/Dy...4HR-10_001.asp

In a 305, installed 4 degrees retarded (???) with swirl port heads (no matter how ported), and a throttle body that flows less air than a 600cfm Holley 4bbl carb, I don't see how it could possibly have made more than 300 hp. In a 3,500lb car, that don't get you 12.40s

Similar to the Cam I'm putting In my 355tpi, 08-501-8, I'm hoping for 300hp.

A guy tried to sell me that cam, but the 110 lsa scared me.

Any trouble betting the ECM to work with that tight lsa?

Dude the car was 3400lbs with driver and with that cam I have a 355 that I built that laid down 410 hp 425trq to the wheels! Now that was using a 2" TBI base on a multiport conversion, ported sportsman IIs, EBL tuned by me. Now that build I do have vids, dyno and time slips in my possesion.
The 305 ran the times and made the numbers period. I know how to build cars and when I get the stuff on that guys 305 I will post it and then I'm done with it. lol

I see there is a lot of stuff that is not known. LSA is only a number, to understand how a cam will work with EFI or how it's idle will be is a lot more complex. It's not so much the LSA number but the total overlap that the motor sees. DCR is also a big factor. Once you understand all of what a cam does the door will be open to getting a motor to do exactly what you want it to do.

That cam passed the smog test in that 355 back then with a single cat and idled at 650 rpm with no lope after I tuned it!

Oh, well, 3400 lbs, instead of 3500. Why didn't you say so? That changes everything!

That cam comes out of the box with 4* advance...106* ICL...If it is in fact 4* retarded, that would be 114* ICL and I could see 340-350 HP out of a 305 using that cam and a set of 1.94 valve swirl ports. It would make more than 300 HP with untouched swirl ports.

I am making 300 RWHP and 350 RWTQ on a Mustang dyno with less duration and lift from an untouched L31 with stock heads breathing through the junk stock L31 truck intake with all the injector crap in the way and B-car LT1 exhaust manifolds.

454 TBI out of the box is 660 CFM @ 1.5 in/hg and the IAC port at 255 counts can contribute another 50 CFM!

I modeled his engine with my Desktop Dyno software and it shows even with stock 350 swirl port head flow numbers right at 355 HP @ 5,500 and 365 TQ @ 4,000 which I feel is about right...

FUNNY THING>.....I modeled his engine setup in a 3,400 lbs car with CarTest and it spit out 12.9 @ 107 and I could not model a launch above 1,000 rpm without spinning. I could go into even more specs if I had numbers like the torque converter STR, brake and flash stall, wheel weight, tire circumference, front/rear weight bias, temperature, humidity, and altitude, etc. The numbers add up to me.

With todays tuning, cams and parts availability it is NOT HARD to build power.

The SR heads in that build flow like junk 882 heads.

To further boggle peoples mind in disbelief....I recently trapped over 98 MPH in a 5,240 lbs race weight truck (with me in it) with an engine that is internally untouched and only rated at 317 HP! Intake, Exhaust, Electric Fans, Ported Throttle body and Tuning are the only modifications. I do not have headers, still have cats, still running an open differential, on 84 lbs each 20s, only put down 296 RWHP yet ran a 13.987 @ 98.37 on a 2.02s 60' time.