BMmonteSS

Ok, my head just exploded from the bajillion’th 305 to 350 swap question. So I’m going to compile some info here and just post a link from now on. You more experienced guys feel free to add or correct me where I’m wrong.

The age old 305 to 350 swap is probably one of the most popular swaps. Here is a list of items you need to make the swap, followed by an explanation of why you need them.

YOU NEED:

350 injectors
350 specific knock sensor
350 ESC module
350 chip

WHAT WILL WORK ON BOTH ENGINES:
Intake
Throttle body (the truck TB’s might have different throttle cable hookups, but otherwise are identical to the car variants)
Injector pod (although it’s easier to swap the whole 305 pod for the 350 pod)
Exhaust
Distributor
Accessories
ECM (as long as it’s a 746’)
Flex plate
Starter

WHY YOU NEED WHAT YOU NEED:

INJECTORS: Stock 305 injectors are 55 lb/hr, stock 350 injectors are 61 lb/hr, if you use 305 injectors with a 350 ecm the computer will think it has the stock 350 injectors and run lean. Get these from a junk yard or check e-bay.

KNOCK SENSOR: The knock sensors are different because they are tuned for the bore size of each motor. Get this from the junk yard or any parts store (I suggest new because they’re easy to damage taking them out).

ESC MODULE: Tuned for knock sensor and engine. Get this from a junk yard, e-bay, or any parts store. In a pinch you can get by with the 305 module, but I don’t suggest it.

CHIP: This is the most important part, the ECM is a speed density system which means it relies heavily on calculations to inject the proper amount of fuel. One of the bases of those calculations is the cylinder size and injector size. If you use a 305 computer and injectors on a 350 it is going to run LEAN because the ecm thinks there are 50 less cubic inches than there really are. If you just throw 350 injectors on there it will throw the whole tune back to the rich side because you will then have injectors that are much bigger than the ECM thinks it’s controlling. It won’t balance out with a 305 ecm and 350 injectors.

WHERE TO GET YOUR CHIP: The 746’ ecm was used in F-Bodies and Caprices, you could only get a 350 with TBI in the caprice. So you need to get your chip for a caprice, the “cop car” chip is popular because it has the speed limiter deleted and is set up for the larger cop car 65 lb/hr injectors, you’ll just have to source the cop car injectors (try eBay). A lot of people here get their chips from TBI chips or some other mail order company. I’m personally against giving these people money, but they cost about the same as a stock chip from GM ($80-120$) and you get some basic things done like the speed limiter delete, more timing, and unfortunately more fuel at WOT (you actually need much less). If you are going to be doing any major modifications to your 350 at the time of install or in the future, you may want to consider getting the chip burning equipment. It cost in the neighborhood of $120-$150 and you’ll be good to go for any modifications in the future. I’ll supply you with a 350 bin file (I’ll even make some “performance modifications”), or you can download them from one of the many sites that have them (Moates.net, tunerpro, ect.)

A word about the stock fuel pump, the stock camaro fuel pump is almost inadequate from the factory. So there is a good possibility that your 100,000 mile stocker might not be able to keep up with the added fuel demand of the 350 at high rpm’s. If you replace it go with a TPI pump or a walbro 190, your regulator will cycle the extra fuel volume back to the tank. Remember the regulator determines your pressure, the pump simply provides the volume.

Anything I missed? Anything need expanded on?

Lewism111

Yea a dumb question I have will everything work like gauges and what not will anything NOT work Im wondering because I have a 1980 350 Carb which Im gonna take my manifold and put it on the 350 and leave it a tbi

robertfrank

iTrader: (27)

If this doesn't become a sticky I'm going to smack someone!! Good job Monte.

DM91RS

bajillion’th ....................

BMmonteSS

Hey it's a word.......I think

Yes all your guages will work as long as you hook up all the sensors. The temperature and oil pressure guages use their own sending unit. The tach signal has it's own hookup at the dissy as well.

Fast355

iTrader: (2)

BTW, the 305 ESC module is the same as a 350, atleast on trucks.

dctrumpet

iTrader: (10)

ESC modules on our cars are different. 305 and 350 knock sensors are different part numbers as well as the ESC modules. I just completed this journey into the 305 to 350 swap. I did all the ultimate TBI mods along with all the bells and whistles, lol.

How do I post a "sticky" so I can put all the part numbers for EVERYTHING that works with our 3rd Gen cars? I mean ALL part numbers from ESC module to injectors to hedders to wires to plugs, etc. etc etc lol.

I have appreciated all the help here on third gen.org You guys are awesome. I want to put a plug in for Brian from tbichips.com and Craig Moates from Moates.net. These guys are awesome with tuning our cars. Highy recommended!!!

Thanks for everything

BlackBird92

Well done Monte! This is all one needs to know if a 305 to 350 swap is considered.

Just one thing: AFAIK the 305 injectors are 55# and the 350 are 61#, the copcar injectors are 65#.

BMmonteSS

Ahh, good catch the 4.3 injectors are 45 lb'ers. Will edit first post to reflect correction.

Fast355

iTrader: (2)

Yep

Early 9C1 injectors are 65 lb/hr. The later bubble bodies are 68 lb/hr. Some 1996 G-series vans had 72 lb/hr injectors in their 350 TBI-Vortecs.

Now I just need to send emails out to Extremefi! They are giving out ALOT of mis-information on their ebay sales. I called out the owner on the fact that he is calling 4.3 injectors "UPGRADES" from 305 injectors when in fact they flow 10 lbs/hr less EACH and he ignored me.

Here is another where they are saying that the 5235206 injectors are 55 lb/hr. I have personally flow benched several sets that were all right at 61 lb/hr each.

There is no way that a 305 could even make its advertised HP with 40 lb/hr injectors in it.

dctrumpet

iTrader: (10)

Yep he is a very poor business man. His communication skills are severely lacking and i as well question his products. I did get some injectors from him and he stated that they are rated at 55lb/hr @ 12 psi. Not sure. I dont have the capability of testing them myself.

Thus, I have been having troubles with my recent upgrade/swap and i am wondering if my injector constant BPW needs to be readjusted. I am thinking the injects that I have are 61lb/hr and not 55. I am right at 13 psi.

I only recommend CFM-TECH.com at this point for ported throttle bodies, manifolds, etc.

Those guys seem to know exactly what they are doing.

GOOD LUCK.

strocker383

it seem easy to swap now but do u know if all that will make my 350 with vortec heads run good for everyday

WheelsUp84z

iTrader: (2)

one quick question on this, when going from 305 to 350 on a TPI set up im assuming you'll need the knock sensor, ecm, and 22lb or higher injectors?

BMmonteSS

It depends on if the knock sensor circuitry is on the memcal or not. I'm fairly certain that the 730' ecm has the knock sensor stuff on the memcal, but I don't believe the 165' ecm does.

Boogie123

Probably a dumb question but what exactly is the ESC module?

Jtufts

the ESU is the computer if i am not mistaken =)

DM91RS

Electronic Spark Control

gheatly

iTrader: (2)

great sticky thread. My car had an incomplete 305-350 conversion.

GM still sells the ESC (also called an HEI module because it fits inside of the HEI distributor). It is pricey at around $90. The "talk" back in the day was that the GM product was better than what the aftermarket offered because it had more sophisticated circuitry. Anyway, I went with the GM module.

All that's left is the knock sensor - I didn't think about that one.

BMmonteSS

Hang on a second, just a wee bit of mis-information here.

Electronic Spark Control Module AKA: ESC--Flat pancake module that has a 2' or 3" wide connector, I believe it mounts to the same bracket as the MAP sensor on some models, mine was mounted on the fender.

Ignition control module: AKA: spark module --This is the module that is located inside of your distributor which does NOT need replaced.

Engine Control Module AKA: ECM, computer, brain-- This is what all your wires plug into and what controls your fuel injection

gheatly

iTrader: (2)

Sorry for the confusion... still getting used to all of these new acronyms.

Question: How many varieties of 350 knock sensors are there? From scanning many posts, it seems like there is at least one for pre-roller cam engines and one for roller cam engines, with the roller cam sensors being a little less sensitive to take into account the additional valvetrain noise.

Is there a difference between truck and car sensors? Is any year better than another?

I have a modified car, so I am leaning towards a later year version with less sensitivity.

gheatly

iTrader: (2)

I went to the GM dealer this afternoon to do some research and to order my new parts. As noted above, I found that the knock sensor and ESC module need to be paired. A 350 knock sensor should be used with a 350 ESC module. The 350 and 305 parts have different part numbers.

There are 2 ESC modules and knock sensors for 350s. For those of us without roller cams (i.e., 1984-1986 models), you need the following parts:

ESC module - GM p/n 16126761 (cost me $109.89)
knock sensor - GM p/n 10456287 (cost me $58.48)

I originally asked for parts for an '84 Vette with Crossfire. The parts guy said that these two parts work in ALL 350 applications for those year models.

1987-up engines have more knocking sounds in them due to the aggressive nature of the opening and closing ramps on the roller cam. Thus, the knock sensor is different. These year models have different part numbers.

I saw these part numbers in a post where someone was doing a 305 to 350 conversion in a 1990 Firebird. He used sensors from a 1990 Caprice 350. Those part numbers were:

ESC module - GM p/n 16128261
knock sensor - GM p/n 10456288

BMmonteSS

Way to bring the tech!

gheatly

iTrader: (2)

Just a note - the 84-86 Vette ESC module may not be the best way to go depending upon the year of your car. The Vette module was mounted in the engine compartment and is a sealed unit that requires a 5-pin weatherpack connector.

At least on the 82 Camaro, the ESC module is mounted under the dash next to the ECM and it is not a sealed unit. The 82 Camaro version also does not use a weatherpack connector. Rather, it uses a card-edge connector.

Thus, if your model of car has the card-edge style connector, you will have to upgrade to the later style weatherpack connector in order to use the Vette ESC module. I was able to order the correct weatherpack connector for $6.00 from Painless Wiring.

cheppibear

Just curious for those who have done the conversion (and or the conversion from Carb to TBI in general), how much does this run? Total cost?

Is it better to purchase new stuff and try and put everything together yourself or purchase a complete kit from CustomEFIS or Affordable Fuel Injection already built to your needs?

Pros, Cons ? Cost effectiveness ? Reliability ?

gheatly

iTrader: (2)

Update on 305 - 350 compatibility.

It appears that some sensors and ESC modules may have been used on both 305s and 350s. I was looking around on rockauto.com and their parts search indicates that the ESC module and knock sensor is the same for a 1983 Crossfire Camaro (305) and a 1984 Crossfire Vette (350). I will have to confirm next time I visit the dealership.

dwillis

iTrader: (6)

Before you all freak on me!I read this whole thread now Let me throw an iron into the fire here...I have a 92 RS that I am going to do this swap on...the doner engine is coming from a 90 model chevy full size van...I am assuming all the sensors will be correct for the swap..I'll use my bracketry to get the accessories down under the hood....
But my main concern with all the ecm and esc modules etc.....My car has a T-5 in it and thats throwing me off I have a computer from an older model truck with a tbi but I dont think it was a 5 speed....what kind of mods will I need to do differant since my car is a T-5.I know to put a new bigger clutch assy in it but other than that..any help will be appreciated and maby this will help others too...Thanks....Dave

dwillis

iTrader: (6)

Anyone?

GMZombie

ok im going to be doing the swap from my 305 to my semi built 355. Now with the bigger more rough idle cam will that work with the tbi? i like the tbi way better than the carb i was using as i wouldnt have to change any wires in the car. the motor itself just bored .30 over with standard pistons stock 327 Heads and the .480 lift comp cam. Will this even work with a tbi?

Colts45s

ok zombie I'm doing the almost identicle swap into my 92 rs. Except 305 tbi-350tbi. What I have run into is this. That cam is a good cam and will fil your application fine. make sure you look into the kit wich comes with the lifters. also the larger cam could effect your vacum signal so make sure you do your homework on that b/c that could potentionally lead to disaster when power assisted brakes um dont work so you might look into a canister if you find it will drop vacum dramastically. plus check your torque converter even if you can run that on stock converter you might want to check condition of your old one, **speaks from bad exp**, that cam should work fine though with your tbi unit, but deff make sure u go with the larger injectors otherwise you just kicking yourself in the ***** every time you go to run her just sitting there gasping for fuel hope this helped sorry if it didnt

BMmonteSS

I'll answer a few questions. For the gentleman with the T-5, the problem you'll run into is that there was never a 746' ecm that had a T-5 and a 350. You can try running an automatic chip, you'll have a check engine light and you'll loose your shift light function but it should still work. Your going to have to give it a whirl or get into DIY chip tuning.

For the gentleman with the rumpity cam. Don't even try it without planning on doing DIY chip tuning. Even an ultra mild LT1 cam will cause enough drivability problems that you'll regret it. You just simply can't make that many changes and expect the stock tuning to handle it. It might run, but you'll be nowhere near your power potential and it'll have all kinda of little quirks and bogs. Don't think that this is a "tbi problem", you'll have this with any kind of speed density (map sensor based) system.

dwillis

iTrader: (6)

thanks monte....I called tbi chips and they will burn a chip for me so it will all work good enough for what I want....thanks again

GMZombie

so BM you say i should look into Prom tuning. Now do you think that just changing some things in the prom will make it work right or will i have to get a performance chip for that application. Also i may be getting a t5 transmission to put behind that 355 will there be problems with that? Sorry for hijackin thread

dwillis

iTrader: (6)

if your good at prom tuning you can do alot.....I just dont know what all I need....I'm the kinda person that needs to be shown first....lol

TRICK_Z28

guess what, im doing a swap to what a suprise . now i have an 82 camaro, that i have installed an 88 iroc tpi system on, the engine in the car is a 355. now i have changed my esc and my knock to the ones for the 86 vette, i have a 125 psi inline fuel pump, and a BBK AFPR. NOW i hav e herd of guys useing the 305 injctors and the ecm all they did was adjust the fuel presure. dose anyone have any thoughts on this. i adjusted the fuel presure to 62 psi but havent run the engine yet, just because i am woried. how will that engine run and how long can i run it

92RS(real slow)

this needs to be sticky lots of good info, and much easier than having to search

BMmonteSS

Dwillis,

Good luck with the mail order junk, I've helped some guys with just a TB swap and the TBIchips.com chip couldn't even get that to run correctly. The truth of the matter is that there is just so much that needs changed there is no way to guess out of thin air what an engine will want. The only way to get it right is to datalog and tune then repeat untill your happy with the result. My first tune took almost 500 burns. I can get a motor tuned pretty good in about 25-50 chips now that I know what I'm doing.

Fast355

iTrader: (2)

With MAF it has taken me only about 10 burns to make it run correctly.

jskopic

I'm in the process of doing this swap right now, all the parts needed can be sourced from your local autozone for 300 dollars with the exception of the PROM which can be gotten from TBI Chips for another 100, and this is all new parts with caprice police car injectors.

BronYrAur

iTrader: (1)

apparently you haven't read the innumerable amount of posts saying you won't get by with a TBI chips prom.

DM91RS

Hey Jim....................maybe we could start up TBI CHIPS BY US or something........sounds like they will sell........

dwillis

iTrader: (6)

I wish you guys lived closer so You could help me out with this crap...I've read thru the stickys and posts and I just dont know what I need nor do I understand how to do it..lol...so do you have any other suggestions than tbichips?If so feel free to share cause I'm getting my engine this weekend to start on..thanks

Fast355

iTrader: (2)

This information is provided that you have a 8746 ECM and not the 8063 (only used in 1988). I would switch to the 8746 ECM as it is a pin for pin replacement for the 8063 and available anywhere for under $50.

Keep in mind that it is best if you have a laptop. As long as it functions and has a USB port all is good.

Download TunerProRT. Go to the Moates.net file library and download the Definition file $61 and the BIN file ANLU which is a 9C1 350.

http://www.moates.net/files/3)%20Bin...0Motors/61.xdf

http://www.moates.net/files/3)%20Bin...208746_TBI.xdf

http://www.moates.net/files/1)%20Sto...5/anlu5369.bin

http://tunerpro.markmansur.com/downl...ProRT_v414.exe

Also buy or build an ALDL cable and download WINALDL for dataloging.

http://winaldl.joby.se/winaldl_109e.exe

http://winaldl.joby.se/aldlcable.htm

http://www.aldlcable.com/sc/details.asp?item=aldlobd1u

Buy a Moates Burn1, G2 adapter, and some flash chips.
First find out which G2 you will need. The factory Prom has two different pin spacings. .45" and .60" are the two.

http://www.moates.net/product_info.p...products_id=37

http://www.moates.net/product_info.p...products_id=36

Here is the USB driven Moates Burn1

http://www.moates.net/product_info.p...products_id=48

Here are the Flash Chips

http://www.moates.net/product_info.p...products_id=39

This will set you back around $125.00 or so.

The production police 350 ANLU .BIN file will be closer to correct on your 350 with 68 lb/hr injectors than the work I have seen come out of TBIChips.com. He generally makes things into a rich running, pinging nightmare. I have personally tuned 3 vehicles he took a swing at first. In all three cases I ended up reading the stock chip and going from there. I have also seen some other .BINs that he created, all equally bad.

Basically for about $125.00 you have 3 options.

Moates Burn1, G2 adapter, and flash chips
TBIChips.com
Factory GM ANLU prom

Even if you only burn the factory ANLU calibration into the ECM for now you are money ahead by having the equipment.

Moates.net will even solder the G2 adapter into the ECM for a small fee if you do not feel comfortable with soldering. All you have to do is buy the installation package, ship your ECM to them, they install the adapter, and send your ECM back to you.

http://www.moates.net/documentation....entation_id=10

http://www.moates.net/product_info.p...products_id=71

DM91RS

Chris has laid it out for you guys.............you can spend more dough on a cam swap and still not have it run as good as a full exhaust change and a good tune..................

Fast355

iTrader: (2)

An near stock 305 TBI with 1 5/8" x 3" headers, 2 1/2" duals with X-pipe, 5,200 RPM Governor in the 700r4, 1.6:1 rockers, 1" open center TBI spacer, Ultimate TBI mods, AFPR @ 18 PSI, and Prom Tuning has run 10.80s @ 65 MPH in the 1/8 in a heavy 1991 G20 Van with 3.08 gears and a 700r4.

I know I said that it was a 350, that is what the guy told me. I found out differently when I saw that the casting number happened to be the same one that was on my old 305 in my G20. Thats right it is 14010203. Apparently I have an mid 80s 305 block, 193 swirl ports, an unknown compression ratio, an unknown hydraulic flat tappet camshaft, and a 350 TBI setup on top. Doesn't seem unhappy with it.

It is most likely a stock flat-top piston shortblock with the factory 929 350 cam, stock 193 heads, and 350 TBI setup (No wonder it has always ran rich).

https://www.thirdgen.org/forums/tbi/...350-track.html

dwillis

iTrader: (6)

Thanks alot fast...I like to mess around with electronics,I'm just a little weary when it comes to something new....
I program security alarms every day for work....all this stuff with proms and chips is all just a series of numbers that are put in the corrosponding order and location...
My problem I guess Is fear...lol...I'm gonna try to pick up just a cheap laptop just for this project....I'm assuming it doesn't have to be anything fancy right?just as long as it has a usb port..and was made in at least the last few years....
Is there anything I can do just so I can get my engine running for the time being..It doesn't have to perform to it full potential but I will have to put the engine in on a weekend and have it running by the next mon so I can drive it to work..Is there a chip I can buy from a salvage yard or somewhere that I can just plug in and go till I can gather up my stuff...
Let me just brief you on what I have
I have a '92 rs...305tbi...5-speed....3.08 open rear....I have done the tbi mods.....open element...3" cowl hood...no emissions<all been removed)...
no cat conv...no egr,smog pump,etc...made fpr adjustable(though I still dont have a guage)...and a useless tbi spacer....
Now I am getting a 350 tbi engine from a '93 silverado...I have an edelbrock intake,and a carb to tbi adapter...shorty headders...I will be putting a different cam in to up the rpm range in the engine....but other than that everything will be stock......If its too much to help with I understand,But I do appreciate all you trying to help me....Thanks...Dave

Fast355

iTrader: (2)

Grab a PCM and harness connectors from a newer 350/4L60E Truck PCM and repin your connectors to use the truck ECM. That way you can switch over to MAF a little later on and save yourself a headache. I can post up a chart to show exactly which connection to put into which slot on the newer style connectors. Took me maybe 45 minutes to repin my connectors on my G20. Eliminate the ESC module and connect the knock sensor straight to the PCM. The 1993 truck engine even has the correct knock sensor to use with the PCM, a $30.00 savings.

dwillis

iTrader: (6)

I've got a pcm from a '90 model truck I believe..the service # on it is 1227747 will that work and I have plugs with about 6" of wire on them...

Fast355

iTrader: (2)

Well the 7747 is a pin for pin swap from the 8746 (meaning unplug the 8746, plug the 7747 in, and start the car), although you will lose the function of the IAT and the Power Steering Pressure switch. No big deal either way.

Actually I was talking about the PCM from a 1994-1995 1/2 ton Chevy Van, Truck, SUV.

dwillis

iTrader: (6)

which one would be better...I could get one of those pcms pretty easily ...but I could actually just plug this one in that I have and start the car......what does the iat and the powr steering pressure switch do anyway...nothing for driveability right.....will it hurt to run the pcm I have (7747) for awhile before I do the computer mods
And thanks for helping man..

Fast355

iTrader: (2)

The power steering pressure switch is used with an anti-stall routine in the 8746 and the IAT is used for a little more timing advance in cooler weather. The truck 7747 has some advantages of its own. I would keep the 7747 for a while, then switch to the newer style PCM.

This is one of the things that can be done with the PCM.

http://www.youtube.com/watch?v=7nVQePIYzhI

http://www.youtube.com/watch?v=c4CY3...elated&search=