First_Formula

Hey guys, I was bullshitting with my mechanic (me 19 years old he's 70) so naturally he believes in the old school stuff and I prefer the new slighly tech-y stuff,
like he wants me to me to throw a 600 carb on it and i want a tune port injected etc...

Currently i have a stock l03 and i was wondering what kind of performance i could get out of a set of 194 heads and a TPI intake manifold to boot, Also if that would bolt up to the block properly and if the TPI intake manifold would bolt up to the 194 heads...
I can see a problem with the 194 heads being larger than the stock (combustion chamber wise) so i might have to shave them down or something... not sure the exact specs or anything
The other route i was thinking for a few ponies was TPI intake manifold and trickflow 58cc heads eliminating the need for shaving or anything of the nature

What do you guys think? while i'm at it should i get a mild cam or leave that stock...anybody else running a similar setup?

RFmaster

Sorry to break OM heart but tell him to keep that venturi mixer on his model T!

TPI will make little or no difference on your current engine since the limiting factor on a stock LO3 is a tiny (TBI) cam and restrictive exhaust. To get the performance out of stock LO3 bottom end you'll need to yank the bump stick and get a low restriction exhaust. LO3 TBI is equipped with 55 lb-Hr injectors (at 13 psi) - and to support potential 220-250 HP you'll have to update your TBI injectors to 61 lb-Hr truck injectors (from LO5 - $10 from your local JY) and up fuel pressure from 13 PSI to about 15 PSI. This will require tuning (aka EPROM) - TPI is not really needed.

//RF

UnderCover89TBI

iTrader: (25)

So basically you need to decide if you really want TPI or TBI. Take RF's advice on it. And go for it. And if you decide TPI make sure to read up on it in the TPI section of the site so you can really get a feel for what people are doing and what works so you don't waste money and time

ex-x-fire

Get a set of 305 vortec heads, vortec 4bbl. intake, & a tbi adapter. It should make a nice increase in power. You'll still need bigger injectors or an adjustable fuel press. regulator, & tuning.

tonys91rs

iTrader: (17)

i have posted before that i was wanting to do a tpi conversion. i have searched through the threads like is being suggested to you. look through the threads and posts, then decide. i was dead set on a tpi conversion till i read through and compared the costs, work, and results from conversions to upgrades on both the tpi and tbi.
as for me, im thinking of selling my 92 tpi assembly and harness, and picking up a cam, 4bbl manifold and tbi adapter. i already have better exaust.

RFmaster

One additional (fine) point - going to a carb intake may not be a viable option if you live in a state where smog inspections are mandated. In CA carb intake on OE EFI engine is a big no-no (we have eco-idiots running this state, sorry not my choice). Even if you are allowed to install carb intake with TBI adapter plate your hood to air filter housing clearance will be tight (i.e got to check for hood interference).

Over the last couple of years I have built several TBI motors using stock GM aluminum truck intakes (90 to 95) with TB bores bored out to 52mm. These intakes were used on 5.7L truck motors and can be found at your local JY's. Based on observed performance they seem to provide adequate street performance (sorry - no dyno data, no 1/4 mile data yet.). The beauty of this intake it is Aluminum OE - it has all necessary ports for EGR and it looks stock (if you need emission compliance). It is not a hi-rise intake like most after market carb intakes, but this can corrected by installing 1/2" or 1" TB to intake spacer.

Like tonys91RS said - read what others had to go through, learn, ask questions before turning wrenches or spending hard earned dollars.

//RF

First_Formula

Alright, thanks alot! Very informative.
I've got 3 inch pipes from the stock exhaust manifold back and no cat so how much horse do you think that will support?

I think I will keep my throttle body after looking at some of the threads like tonys91rs said and you're right its alot of work for little gain in comparison to just bumping up the throttle body.

The only problem with doing things like that is as of yet.. I have absolutely no idea how to *eprom* or anything like that, nor do i have the tools necessary to do so, if any are necessary, What kind of cam would be good for a mild 220 250 horse build?
I was thinking an lt1 cam or something similar and the 194 heads. That ought a put me around that mark right?

RFmaster

I just realized that you were planning to bolt 194 (old 60's or 70's design) heads on top of a stock LO3 bottom end. Is this correct?

Stock LO3 heads have a small combustion chamber ranging from about 54 to 58cc depending on a casting number, etc which results in compression of about 8.7 to 9.2 depending on piston design and head gasket thickness.
The 194 head will have a much larger combustion chamber 64cc or more likely 72+cc chamber which will significantly drop your CR! Can you post a complete casting number of your 194 heads??

For tuning your new combo you'll need laptop and EEPROM burner - you can find more information on this in the DIY EPROM forum - tons of info and how to's.

//RF

camaronewbie

Consider the following ...

1) Last time I looked, it was about $300 out of pocket to get the equipment to do the chip tuning on your own

2) The ONLY way your ever going to get a decent tune out of a TBI car that has been modded beyond the very little mods a stock chip will understand is to do it yourself.

3) If you've never done any computer programming or much basic ebgine tuning regardless of the computer stuff, you have a very large learning curve here. There's no way you'll get a tune that the car will run half-way decently on within the 1st week, and that's assuming you get are spending everyday with it.

4) (should have been 1st really) There's very very little you can do to a TBI motor without needed chip tuning. You could do cam, maybe a better intake with a TBI adapter, and headers - beyond that the car won't run without major programming mods to the chip. This is from personal experience, not heresay - I've been there and done that.

If your 70 yo bud knows anything worth his salt, he knows what I've stated above and thus his suggestion of 'slapping a carb on it' - which in and of itself is by no means a cheap easy task either.

Now - I assume that your goal is to get more power, right? Based on that assumption, the EASIEST CHEAPEST LEAST HEADACHE routes available to you are ....

1) swap to a 350, and keep the TBI system. You need a prom from a 350TBI motor like a truck or Caprice, the 350 itself, 350 injectors, and a 350 knock sensor. You'll be amazed at the difference between a 350 and a 305 - it's night and day. You could in theory do the swap in a weekend (give yourself 2 weeks in reality).

2) swap to a 350, and go carbed, assuming it'll pass inspection in your area. This will cost more in the end (you need the 350, a carb intake, a carb, a vac-advanced dist, and fp regulator - plus if it's an auto, you'll need a TC lockup & TV cable corrector for linkage). Allow yourself a month for this swap.

The swap times assume you have a life - ie wife/gf, job, etc.

Now - before the chip programmers come in and say about the chip issues - I'm stating this from the perspective of a normal guy that has job, kids, wife, etc., and is not an engine or computer genius, and that (as the OP stated) has no clue about the programming, equip, etc.. I know the programming comes easy to alot of you gurus that have alot of time to 'play' with it, have other cars to drive, and are not as concerned with getting the car back on the road as you are in bucking the system just to prove that it can be done. A Gazillion folks here want to make umpteen million hp out of a 305 just to be able to say it can be done - great - more power to ya!

But - MOST folks here that are normal guys with 3rd gens that would like to go faster want it easy, and want it quicker, and have no intention of proving anything, they just want to get into their cars and have fun driving them - not get frustrated b/c they 'read somewhere' that it can be done but didn;t understand how hard it was, and that the end result is still less than desired.

To the PO - the point I'm trying to make is - The programming/tuning gurus 'played' with the 305 to see what they could get - as a hobby. The rest of the 305 folks that thought they'd save cash and keep their 305, follow suit and try to 'build what they had' - are (in the end) dissapointed that they didn't just do a 350 swap to begin with.

Comes down to the question - Do you want to prove something to the world of 305 doubting Thomas's like myself, or do you want to get more power to the street sometime this year and have fun driving it?

thomas1976

I do not know about the 194 heads, but the TFS 175 you mention, with something like a comp cam 8-500-8, full exhuast, EBL flash, anough fuel/air, VRFPR, ported/bored stock intake and TB should get easy around 270rwhp.

Tuning a computer friendly cam with EBL flash is easy and quick.

You load the EBL stock LO3 calibration with desired fueling changes, do 1 hour of VE learn and the car will run nice.
Then you can play with SA and keep doing VE learns.

camaronewbie

Oh - maybe there's new stuff (this EBL flash) that I didn't know about.

Again - not trying to bash any 305 prom guru's here - it's just that back when I tried it, might as well just flushed $1000 in parts and 2 years in my time. My carbed 350 however was easy, quick, cheap, and makes me very happy

First_Formula

I see your point absolutely. I've never done an engine swap and I'm on a moderately tight budget for now, so a 350 swap would be faster and probably cheaper. I just don't have any idea how to do that yet lol....

The main reason I like the 305 over a 350 is because while it is faster than a lot of the other cars i see running around (mustangs are my main competition) it still gets a decent 20 23 mpg.

A 350 i've always thought got worse gas mileage by a significant amount and it is a tad on the overpowered side. I don't NEED 300 horse to go to work and back , Though had I the option with my 20 mpg intact I'd jump at it lol.
The firebird I'm working on is my daily driver right now so like you said I don't really have all of that time to have it garaged and tuning learns etc, unless it really can be done in a few hours with this EBL flashing(?)

Either way I am beginning to lean towards a 35o swap later on. Possibly in a different body...
As for building an l03 I only wanted to make the engine I have a little more fun/fast. I have no intentions of having a 340 horse l03 lol. I figured a mild cam and new heads would make it pretty quick and it would be relatively easy (I've never done anything of the nature so if I sound out of my league as far as cars go its cuz i am) without damaging the gas mileage TOO bad.

Also I knew the 194s were larger combustion chamber i was just planning on having it shaved down at a machine shop. but if its a 20cc+ difference I don't think that'll be the most viable option...

the solitaire

RFmasters post on fuel pressure and Thomas1976 post on the heads, cam and EBL would be your best bet to keep the car running, have a fairly friendly budget and get more power.

With higher pressure and thus injecting more fuel your mpg will suffer, but most of the other mods (full exhaust from the headers back, including cat and what you already have and a cold air intake of some kind) shouldpretty much even that out, leaving fuel consumption roughly where it is now.

You definately want to get rid of the stock cast headers and Y. All the modifications you do will see litle to no effect unless you get this one big restriction out of the way.

A set of L98 heads with 0,035" shaved off would also work, but they involve a lot of additional work like replacing valves, springs etc. For low end power you could consider porting the stock heads and see what that brings, but porting takes time and your car will not be running untill porting is done, unless you can pick up a set of cheap stock heads. Do not expect anything above say 5000 rpm, but then again, that should suffise for street use.

RFmaster

High fuel pressure should be implemented with EBL modification. Actually, higher fuel pressure helps fuel mileage by allowing injectors to spay a finer mist of fuel. As long as ECM is operating in close loop fuel millage should be the same or even slightly better. The trick is to modify VE tables to account for increase in fuel pressure and other engine modifications.

As for milling down L98 heads down 35 mills - I would have to disagree with this approach - too much machine work plus intake manifold to intake ports alignment issues afterward. While it can be dealt with - it is a headache I like to avoid. A simpler and more cost effective (long term) approach for your LO3 would be:

1) swap TBI cam with LT1 or equivalent roller cam (keep LSA around 112 deg and duration below 215 deg at 0.050). Look around - there are plenty of them floating out there.

2) Find a pair of 059 Vortec heads and modify them to accept beehive LSx GM springs 12499224 (about $65 for 16 from SDPC). This mod will allow up to 0.550 valve lift with a minimum cash outlay. Com cam springs (918) are almost +$100 more expensive. Keepers, seals and full roller rockers should make a complete performance package (this is extra that you should budget for).
http://www.carcraft.com/techarticles...ade/index.html

4) If you are going with 059 vortec heads you'll need vortec style intake. GM performance offers vortec TBI intake, but it is pricey. I hate to say but a carb vortec intake with TBI adapter plate is straight forward approach.

5) EBL from Dynamic EFI - stock calibration is conservative (plus it would make tuning your engine combo a lot easier)

6) Replace stock TBI fuel pump with higher pressure fuel pump if you are planning above. Get Jet adjustable FPR or make your own. Get a spare TB from JY and 61 lb HR injectors.

7) headers - stock exhaust manifolds are restrictive. Enough said.

This would be my short list (I probably forgot a thing or two) - but if planed correctly you can collect parts while driving your car and then make a transition.

//RF

UnderCover89TBI

iTrader: (25)

350 doesnt get that much worse fuel mileage than a 305. really on 2-4 mpg. not enough to point your nose up too. from what I have seen anyway.