What do you guys think it would take to make a bone stock 305 tbi put out 350 hp. I don't want to do an engine swap cause I would have no idea where to even start there. And im not the most mechanically inclined person in the world. So I want to know what it would take to make my bone stock 305 put out 350 hp. Without using the bottle cause thats just a cheap way to gain temp boosts. Oh yeah and I would have to find someway to pass emissions to.

 

World S/R Torquer 305 Heads or Vortec heads
Edelbrock carb intake
Holley or 454 TBI
LT1 camshaft
headers, hi flow cat, and 3" cat back
custom chip tuning
good tune-up
open element
mics. mods like tbi spacer, injector spacer, ultimate TBI mods, crank pulley, etc..

and 3.73 gears, posi and a higher stall torque converter will not add any power but would knock a good 7 tenths off your ET.

Im not sure exactly how much power you will have, but your car would be fast a hell compared to stock.

 

how much hp can the 454 tbi handle?? the flow numbers and all. i was under the impression 350 is near the max it can support..
Shawn

 

im sure if you did the mods i listed you would just about be pushing the limit of the L03. Im sure the 2" 670 cfm holley TBI with 55 or 65# injectors would be able to feed a built up naturally aspirated 305.

 

Unless you use the bottle(with headers, a good fourbarrel intake and a better than stock cam) or a supercharger/turbocharger it would be easier and cheaper to make 350hp out of a 350ci engine.

Steve

 

FIRST... the 454 TBI can handle UP TO almost 700 HP... BUT
SECOND ... the 454 TBI WILL flood the engine... ALL THE TIME, It WILL NEVER RUN... 80 pound injectors ARE WAY TO MUCH,.. condidering STOCK are 45.. look for 55 (from a 350) OR 65 (from the older cop-cars)
THIRD... you will NEED MAJOR HEADS, and a pretty RADICAL CAM, and an after market INTAKE to get remotely close...
FORTH... if you wanna START WITH SOMETHING... you WILL need headers/3" cat-back (probably WITH OUT the cat) THEREFORE ... not emissions legal.. UNLESS YOU HAVE A HUGE CHECKBOOK
FIFTH... you will need AT LEAST 3.45 gears, torque arm/ control arms/ MORE SUSPENSION STUFF .. so your car doesn't break apart when you punch it...
SIXTH... GOOD LUCK... I'm trying to do that right now with an '89 305 TBI... I've been working on it for over a year and I'm RIGHT AT 320 HP/ 375 ft-lb torque .. HOWEVER I HAVE MINE TUNED to get about 16-18 mpg city/ 23-26 highway... If you have questions about what parts to use... let me know.. I've wasted SO much money on CRAP that didn't do CRAP...:rockon:

 

I know EVERYBODY says it ALL THE TIME... BUT.. DON'T UNDERESTIMATE A 305.. the MAJOR difference between a 305 and a 350 is that the 350 HAS A 4 BOLT MAIN... basically it can support MORE power because the crank in supported MORE... the ONLY OTHER DIFFERENCE is a .264 inchSMALLER bore diameter on the 305 (that's JUST OVER a 1/4 inch, for those of you NON fraction people)... PLUS .. with a 305 .. .you can achieve MORE COMPRESSION because it has a smaller combustion space... AND a 305 WILL react more to the same MODIFICATIONS done to a 350...(because of the smaller combustion area, with the same [intake, heads, whatever]) I SAY... DO IT TO IT, Man , I had SO many people say "hey man, get a 350... it's SO MUCH BETTER" I say... "wanna race" I was cheap that's why I started building up the 305... I couldn't afford a 350... NOW, I like being able to stop at a light... WAIT for the guy I just smoked, and saying .. YEAH It's a 305 why ??? It makes you so proud.. :rockon:

 

Your gonna need more than an LT1 cam to make that kind of power. With my setup, I bet I'm lucky to be around 300 hp at the crank perfectly tuned. My goal is to be a solid low 14 high 13 sec car with the setup I have now. If I did it again I'd go with a bigger cam. When all the bugs are worked out I plan on twin turboing it with the bottom end rebuilt. Should be a low 12 high 11 sec motor, I think.

txhotRS, what setup are you running? I'd like to compare notes alittle to see where I can improve. I still need a 670 tbi for sure but I'm always looking for more power.

 

The easiest way would be an engine swap. Quite a bit of work but not too hard.

I started out in your shoes about 2 years ago with my 305 TBI. I went with a full exhaust, professionally ported world s/r torquers, edelbrock manifold, ZZ4 cam (208/221 .474/.510 112 @.05), 55pph injectors, a 100hp nitrous kit, and 55pph injectors. Never got the car to the track before I broke it, but I think with enough fuel and tuning it would have made right around 300hp N/A. Good enough for a mid 13s 1/4 mile. Getting 350hp streetably out of a 305 N/A would be quite task. Just run a few searches see what people are running and what parts they used.

 

Im also lookin for 300-320 hp na. I dont think the LT1 cam was it, either. I recently purchased a Crane 2050 (for LT1s: .498 .498 218 218 116), but I dont even know when that will go in, maybe later this summer but not until July-ish.

I can tell you this from expirence though. All the parts in the world dont mean **** if you dont tune it and you dont have a solid suspension. I fell into the trap that I'd bolt **** on and go, worst thing you can do. I finally got my chip burning **** though and I passed emissions (Ohio ECheck) after a day and a half of tuning. I havnt even started on WOT yet and the car runs 50x better. It was so rich and idle previously that I'd get a puddle of gas that wasnt burning under my tailpipe. Now its great and my blms are right around 125 part throttle. This is after only a day and a half, too! Its cake to pick up the basics. Finally hitting the suspension hard too. Bought BMR subframes a few days ago, and Im doing BMR lcas, lca relocation brackets, and adj phr early May.

 

are yall guys talking RWHP?

 

It should be possible to come close to those numbers. A friend of mine has an 83 which has a 305 in it making 327rwhp! Should be near 350 at the crank. And here's the kicker, with the stock unported heads! He started off with the base block, took everything off of it that wasn't absolutely necessary for the motor to run. He put in a ZZ4 cam, 700cfm Edelbrock carb, Edelbrock RPM intake, and a standard HEI ignition. It's got a straight exhaust. No emissions, no ac, only water pump, power steering, and an alternator. He had the carb tuned professionally and then dynoed to the numbers up there.

His block is a bit strange though, he called it a freak block. Just above the water pump there is a plug in the block that looks like you could put a wrench in and remove it. He says that blocks with that plug were used by NASCAR for xtra oiling purposes. Has anyone else ever heard of that? I saw it with my own eyes on his motor, I've never seen it before.

 

My 305 has a small square headed bolt in it, right below the front of the intake and right above the timing cover.

"I think it's quite standard really."

I'm guessing 300 at the crank is the goal for most. Pulling 327 at the rear wheels is great but he is running a 4 barrel carb. TBI takes alot more tuning plus you only have a 2 barrels to get your flow from. I don't think mine perfectly tuned could pull more than 300 at the crank, but I also have near 120,000 on the stock bottom end. My rebuild is coming up though, so I think I'd like to try a ZZ4 or maybe even a LT4 hot cam with a spring upgrade for those vortecs.

 

I went with the zz4 cam (still have yet 2 get it) and on the 9th of May (my bday :lala: ) ill get my vortec heads and edelbrock performer rpm air gap intake. Anybody have any estimates how many horses and torque I should be puttin out, and 1/4mile times (dont 4 get the mods i already have done check sig) with tuning and w/o , thx guys vclite been a ton of help brotha thx a ton :hail:

 

txhotRS what setup are you running? do you have to pass emmissions? im planning on building up my 305 this summer and my plans are:

edelbrock intake #3704
full 3" catback
LT1 cam
S/R 305 heads
custom chip, etc etc
3.42 w/posi (have but havnt had time to install yet)

my biggest prob is that i have to worry about CA smog test, and i dont really want to have to change out a radical cam for one that will pass smog or anything like that, nor do i want to put in a 350 right now.

 

my set up is VERY similar...
LT1 cam, edelbrock EGR/TBI intake, ultimate TBI mods, injectors, custom chip, headers/3" cat-back... 3.42 posi... HOWEVER my big kicker is my heads... they are GM performance heads with MAJOR port work and 1.94/1.6 valves, plus... one thing I have that NO-BODY ELSE HAS, IN THE WORLD.. a custom HOME-MADE tubular ram-air funnel system... that forces air straight into the TBI throttle bores. this plus knowing HOW to drive and sfc's and control arms = FAST AZZ 305 TBI... like I said .. OVER 310 HP, and NO, I don't have to pass emissions... well, I'm supposed to but I have a friend that works at the inspection garage.. ... If I added air-injector hoses to my headers and put the cat back onto my car THEN YES, it would be legal.. (at a loss of about 20 HP though)
any questions... comments... let me know...

 

nice...so just the air hoses and the cat would make it smog legal? did you do your chip yourself or did you buy it from someone? i probably wouldnt do too much work on the heads and that stuff cause its still a daily driver that needs to get decent gas milage, right now im gettin about 19 city.

 

I have a secret for you... right now I get 16-18 city/ 23-26 highway... that is mostly the work of the LT1 cam and the chip (which I bought from a guy online... for $30 ... go to tbichips.com )

 

im interested now...

Do you have data from a dyno pull? Id like to see what the power curve looks like, just out of curiosity. Also, what does it run in the quarter mile?

As for the 305, the only difference is just teh bore. Journal size is the same and just like most 350s, its got two bolt mains. From what i hear the major restriction is its smaller bore which results in valve shrouding and the smaller bore prevens use of larger valves because theyll hit the deck. Just a few things to think about. If your engine has alot on the ticker its not a bad idea to consider changing it out. If its realativly new,. though, then by all means, mod away.

 

i was thinking about getting a chip from that guy once i got all my mods done but people were saying that it would be better to have a chip made specifically for my car (which is exactly what he does if you send him your data) so i got kinda confused. do you like the chip?

 

well here is my combo....

ported/polished 416 heads
weiand 7525 single plane intake
comp xr264 cam (208/212 .488 .495 112)

i am hoping to creap up on the 300hp mark with that combo.

to go to 350, i think you could do it with a larger cam, like the ZZ4, and some better flowing heads.

on another note, if you get 350 hp, i am betting you make above 300lb/ft, so if you have a manual tranny, you will want to watch that and be careful. plus you will want to run SFCs and do a few suspension mods to lay the power down.

 

get a zz4 and tell everyone its a 305 TBI


and Man-O-Man is this history repeating itself, all you new people, thats like 75% of you or more oughta read back into the archives of this board starting at about 5 years ago and youll see you making guesses that have allready been proven or disproven, or just plain spitting out incorrect data. Not to be a dick, but hey, if you arent informed, you arent informed. I wasnt born informed for one I had to search like hell for the info thats so easily available today.

going off on a tangent here, this reminds me of the parrallels one can draw from one great society to the next. Like have any of you seen that tv show "Highlander" ? I feel like a highlander that started off in like the time of the phonecians (very early sea faring society that i believe inhabited crete/lebanon?) so I live through their entire existence. They make mistakes, people screw up their rudimentary government with poor decisions. They figure out their mistakes fix them, move on to new problems and the same thing happens over again till their society eventually falls

Then you have what I will call a T'aint period where there is no society but Im a highlander and I just keep living

Some time later greek society grows and I live through that.. and i notice.. hmm these idiots are making the same mistakes as the phonecians and figuring out the same things as they go. They remember like 1 or 2 things but thats about it from the phonecians. Basically history repeats itself
the greek society dies out
another T'aint period comes along and then everyone forgets about the greeks
Mr Highlander is still alive and up come the Romans..
They remember a thing or two about the greeks.. some architecture.. but in general they forget all about the same stupid stuff they tried to pull and make the same governmental mistakes
yadda yadda yadda.. stuff happens all over again, romans die off

taint
then the byzantine empire.. and yadda yadda yadda
stuff just keeps cycling like this and here we are today in the united states and a whole mess of fools are doing the same things that led to the demise of phonecian society, or roman society... only a few of us who paid attention in history know better than to be a part of it as surely existed in the roman empire


the same thing is happening on the TBI board, its a matter of weeks before someone rediscovers that TBI injectors have different P/ns and flow rates, or color coding.. or that 454 TBI units have different IACs and have been flow benched at 670 cfm at 3" HG... then there will be the rediscovery of the 80th time that all flow rates arent equal, 1.5 or 3" is a big difference.. and so on and so fourth. In about a year the TBI board will have another exodus and new people will be in talking about what a spark plug does

That is my observation for the day... Enjoy

 

i guess that shows our age pablo :-(, we actualy know the highlander movies!

BTW, nice analogy, but i don't think it is the end of civilation if we have a few post re-appear, that way the newbies can read some of this info since most people don't figure out the search button until their 1000th post or so

 

First, how do you know the 454 TBI will handle up to 700 HP? It only flows 670 cfm @ 3" HG. Second, why can't he run a high-flow cat? It won't cost him much, if any, horsepower. And good high-flow cats aren't that expensive. Third, suspension stuff is always usefull, regardless of your combination. HAHA, where did you get your HP and torque numbers. Wait, I know, DD2000. LMFAO.
Ok, I don't even know where to start. Why didn't you just edit your other post and add this information? You're wrong about the mains thing. The differece that people care about IS the bigger bore. The 350's is better. That's why people don't really build 305s. That's why you dont see 400HP 305 crate engines (besides for the fact nobody would buy one). The compression thing, um yeah, you're wrong on that too. You can run all the compression you need on a 350.

You plan to spend money on a forged bottom end for a 305?

HEY!!! At least there are a couple people that are on the right track.

Those numbers are very hard for me to believe. Mainly due to his heads. But then this bit of information kinda confirms that he probably doesn’t know what he is talking about:

There is nothing special about that. Nothing special about it at all. The 350 I have in my car has one, the 305 that was in there before had one. I have seen 100s of SBCs that had one.

Yup, it is standard. What you are looking at is a ¼” NPT plug, IIRC.

I don’t think it matters all that much if you have 2 barrels or 4. What matters is the tuning and the CFM that the carb or TB can flow.
What are the casting numbers off the head? Which head are they? Your custom, one in the whole world "ram air" setup is actually nothing more then a CAI. That's right, those special tubular pipes aren't ramming any air down the TB. Cold air is better then hot air though, so it does have one good point. When you say fast, what's your defintion of fast? I thought a 15 sec ¼ mile time car was fast until I rode in a 14 second one. That was fast till I felt a 13 second one, and that felt fast till I rode in a 12 second one. And on and on. Where did you get your HP numbers? Oh, let me guess, DD2000. What do you run at the track? Houston is a big city and I know yall got a track. Also, are you trying to say that the A.I.R. system and a cat-back exhaust would take 20HP off of your combo? How do you figure? Any real dyno pulls?

I am not an expert PROM guy, but I do know that chips burned without the guy sitting in the car or looking at how the car does on a dyno are NOT the best chips. People need to burn chips themselves.

Are you thinking what I'm thinking (cough cough cough).
Bottom line: you are much better off burning the chips yourself.
I haven't been here as long as you, but I know exactly what you are talking about.




That's my $0.02 on this thread.

 

Brody = :hail:

On the TBIChips.com thing, he asks that you send him some WINALDL data so he can at least be close. Without it, its a shot in the dark.

For the 300hp 305 TBI, sure its doable. But in the end, its cheaper and easier to swap in the 350.

Also, if this board goes on long enough, we will touch on almost every subject. Eventually, it will get to the point where we would almost have no new posts, all threads would be locked, and the only option that really works is the search button. Wouldn't that be nice?

IMO, as long as the questions are not blatently retarded, keep asking.

 

Haha, more like a Dollars worth.

 

brody, you took the words right out of my mouth, same with pablo. I just didn't feel it was worth the time to go and quote everything. It gets old real fast. Thanks.
BTW, 305 is not great, it never was designed to be great, just like TPI was never designed for a 350 nore was it made for making awesome power past 4500rpm. TBI has a similar story except it got put on crappy heads. Moral of (short) story is question everything and don't believe somebody elses .
I'd like to see these ever so powerful 305's with stock swirl port heads making as much hp as claimed. Better yet I'd like all this horsepower to leave for good. Get track times else it's just a piece of paper. I'd rather use the 1/4 mile as a measure of performance. Sure you've got driver error but there are LOTS of reasons why dyno's can be so far from the truth which does include operators error etc.

 

Hey brody....
one, I didn't say he couldn't run a HIGH-FLOW cat, I said it 3" cat-back PROBABLY with out the cat (it's just easier than having one),... that's all..
two, I didn't get my HP numbers from DD2000, know why... because that stupid program told me that I would have over 365 HP with my set-up.. I may be ignorant about some stuff, but NOT EVERYTHING,
third about the 700HP ... I read it somewhere in a search... SO SUE ME IF I'M WRONG, everyone makes mistakes.., I have info from "my azz" and it's wrong, but when I use info that I read in a search from someone a while ago, it's still wrong..and then when the inexperienced people ask questions they are griped at and told to "do a search", It just doesn't make sense to me, I'm just trying to learn, SO I don't make more mistakes
about the 305-350 comparison, I typed it without thinking... I'm sorry, the major difference IS the bore..you are right
just so you know, I DON'T KNOW the casting # on my heads... BUT, I know that they have hella-porting and they work great, for lots of power (way way way more than the same set-up before I had the heads)
BY THE WAY, the tubular intake thingy... thanks for telling me what I HAVE in MY car, ... I know cold air is better, and I know that it helps, BUT.. despite my obvious stupidity... I know AND understand the difference between ram, and cai... the inlet for my "cai" just happens to be facing the front of the vehicle, in a place where air can be pushed into it, with funnels to catch the moving air, through the tubes, with a VERY gradual bend, to an angled collector, (yes, cusom made), INTO THE TBI, .. take a bendy STRAW... when you blow through it you feel the same air on the other side (like a WS6,.. straight ram).. but if you bend the straw and blow through it, YOU STILL FEEL THE SAME AIR on the other side (my intake, CURVED RAM)
about how fast my car is... you don't have to believe me, which is okay, and I can't proove it (because I don't have a scanner), but if you wanna know, I ran a 14.2 @98.45 at baytown (houson race-way park)... and I did get a dyno... yes a real one...
and apparently I had really good luck with finding a chip that worked, if I knew how to burn chips, I WOULD... I'm sorry if it seemed like I'm chucking a load of BS.. but I have no reason to lie to people I don't even know, i just don't like it when people cut me down,.. forgive me... thanks for all the help ..

 

Brody, you have alot more patience than I. I gave up on that sort of thing awhile back, youll just have to do it again next week though.
But hey Im glad someone did it.

 

Well

I did mod my TBI.

I have ported and polished heads , enlarged the intake and exhaust ports all this has been done to stock heads.

I instaleed edelbrock TES and 3 " exhaust
1,6 crane cams rocker arms
comp cams valve springs
`91 genuine corvette spec L98 camshaft
mallory fuel pressure regulator , pressure set at 15 PSI
hypertech custom chip
hypertech 160 F thermostat
open air filter with K & N

and
threw away the air pump and cat

The results were impressive the stock L98 fbody could do nothing but stare at my exhaust and I did prove something to me and my friends with 350s

But now summer has come temperature is 28 degrees celcius here and I have problems. The car often goes to 220 F temp and that`s
too hot for him, moreover the fuel pressure regulator broke down and the result is 0-100 km/h in 9,5 sec ((((

On Monday I`m having new fuel pressure reg installed and my radiator gets modified. Will it help what do you guys think of it??
Might it help?? I want my Formula fastest again

 

The car running up around 220* could very well be the fan switch. If your car has a single electric fan then the switch is in the passenger's side head, between #6 and #8, IIRC. The stock one doesnt turn the fan on until 220+. You can get an aftermarket one that will turn it on sooner.


<---------didnt mean to sound like a complete ********

 

Yup I`ve got one fan and it starts to spin at around 220 F.

 

Welcome to the club.

 

That means in a non-highway driving atmosphere your car is going to get up to about 220* before the fan comes on and cools it down a bit. What thermostat do you have?

http://www.jegs.com/cgi-bin/ncommerc...51&prmenbr=361

http://www.jegs.com/cgi-bin/ncommerc...23&prmenbr=361

 

160 F powerstat from hypertech

 

if you want to stick with that thermostat, i would invest in a new fan switch.

 

thanks for advice , I`m ordering one ASAP.

 

No problem. The fan turn on and off temp and thermostat has got to be matched for best performance...

 

lol broady, tell us how you really feel

 

Chuck, ya pretty much got my true feelings on that one...

 

enhance your calm brody... unfortunately, there are laws allowing retards to procreate, so, this argument will happen again.