engine question

ok i know the only stupid question is the one u dont ask so please be forgiving... well i am planning on tryin to rebuild my first engine which i dont know anything about, but my dad can give some help (he knows how but was paralized and in a wheelchair now so cant get hands on) well i was wonderin i have a 305 tbi now and im gonna go w/ the 350. now the question is should i stay w/ the tbi or go carb, and if i do get a carb one (like out of an old vette mabey a 79 or 82) will it mess things up w/ the computer since it wont be fuel injected and if i dont use the computer wont it mess everything else up??? i cant ask my dad cause he only was able to work on carb'd vehicles before he got hurt. and also and even dumber question....if i do go carb will it clear my stock hood w/ a decent size air cleaner on it prob. 3 inch since its what i got now???

I'm not the most knowlegable by any means, but I'd say stick with fuel injected.

in some cases, i think you can by pass the computer. also, get a cowl induction hood. if you want to use a big air cleaner. or you can cut the hood, i think that looks like hell. if your going to completely rubuild the 305, you should just pick up a 350. you will get more out of it and be happy.

no i am rebuilding a 350 and i was wanting to know about a: how does one go about goin from fi to carb, and keep everything else running normal and b: if i go carb will it effect hood creance more than tbi

well ive got a friend who had exactly the same situation as you. he got another one of my friend's to work on his third gen. the kid apparently just removed all the injectors and stuff, put on a carb intake manifold, and spliced the injector harnesses together to complete the circuit. idea is that it tricked the computer into thinking that the injectors were there and firing. i dont know how it worked but the kid drove the car for a while afterwords. i know there is a better way to do it, but i thought that was an interesting story that was on subject...

my advice would be to stay with efi. find a pair of L98 heads or aftermarket ones that are designed for 87 and newer intake manifolds. your tbi manifold wont bolt up to heads that were made before 1987. bolt those heads on to your 350 block and bolt your old manifold onto it and drop in the distributer.

or find an entire 350 from an 87-93 suburban. those had tbi and are a direct bolt in. your ecm will work just fine with a 350, but you can also get a prom from a 350 equiped vehicle or a have one custom burnt.

if you switch over to carb just drop in an HEI distributer. your existing distributer wont with a carb. it will fire just fine but it wont advance the timing during acceloration, there may be a way to make it work but i dont know how. you'll have to either get a pressure regulator for your fuel pump, or get a mechanical one that bolts on to the block. your stocker puts out about 15psi and that will blow the needle valve back in the carb and cause flooding.

and yes your hood will clear just fine.

thanx alot man u dont know how much i appreciate everyones help!!! i just want to let u guys know its people like u who make ametures like me really want to learn these things that interest me by providing insight that would be a huge block in the road to someone lacking the knowledge

thanx alot man u dont know how much i appreciate everyones help!!! i just want to let u guys know its people like u who make ametures like me really want to learn these things that interest me by providing insight that would be a huge block in the road to someone lacking the knowledge

I could say the exact same thing :biggrin:

my advice, just for the ease of installation, is to keep the FI. if you are swapping in a 350 for the 305, its a direct swap, all the accessories, all the parts that bolt to the engine will bolt right on. if you go with carb, youll be splicing wires, modifying harnesses, and in a whole messy situation that no offence, i dont think you are ready for. The only change youll have to make with the 350 is to get the Throttle body off of a truck at the junkyard orriginally equipped with the 350, i think its the K motor. the Throttle body here is larger and allows more airflow, or you can order a direct replacement from holly with much more airflow. I think even though FI is said to be more complicated than Carbs, that you will have a much simpler job if you keep the FI.

so your sayin i can use any old 350 engine then just get a throttle body and replace it where the carb was right...if thats the case then ive got a world of possibilities because i was worried about the power of a old suburban motor really all the power i want is around 300-350 but i just dont like how damn slow my 305 is off the line although i do need a tune up

I this going from Fi to carb is a step down hill. It all depends on what this car will be used for. If you just want a street racer then build the 350 and throw a carb on it would be just fine. If you might drive this car in winter of daily then stay fuel injected. You can use the 305 hardware but it is not ment for a 350. I do believe it will work just fine though. If I were you I would find a good junkyard that has a Fuel injected car similar to your and tell them you want to trade your 305 with Fi for just a 350 Fi or the engine and all. They might do that if you drive the car in and let them here it run. Have fun whatever you do. Working of your car is always fun.

the only difference between a 305 and the 350 is the water jackets (which wont allow you to bore it out to a 350) smaller bore and obviously the pistons. other than that they are EXACTLY the same engine. so you can build up a 350 on an engine stand next to the car, unbolt the 305, pull it out and put it next to the 350, and swap EVERYTHING from the 305, to the 350, and it will look externaly the same because it is. then take the 350, and drop it into place where the 305 was. physically everything is exactly the same from the 305 to the 350, the engine mounts the tranny (except the T5, use that at your own discresion but dont say we didnt warn ya) rear end, suspension, fuel pump yadda yadda, all exactly the same.

one thing you will want to change, is the throttle body, the stock unit was small even for a 305, so with a 350, it will be the cork in the system, get a bigger one, like i said before.

one thing you will have to do, if you want the engine to run its best, will be to get the PROM chip out of a 350 equipped truck, probly the same one you get the Throttle body out of, and put it in your computer. You will have to find a doner truck from the same year as your car though, as PROMS changed over the years and are not interchangeable.

so your sayin i can use any old 350 engine then just get a throttle body and replace it where the carb was right...if thats the case then ive got a world of possibilities

yes and no. 87 and newer blocks have the dipstick on the passenger side. 86 and older have the dipstick on the drivers side. 87 and newer exhaust manifolds will block the dipstick hole on an engine that is 1986 or older. the only way you can use a motor that is 1986 or older is to buy a pair of headers, or get different exhaust manifolds and get a custom fabbed Y pipe.

your intake manifold like i said before wont bolt up to heads that or 1986 or older because the center 4 intake bolt holes are canted.

no thats not what im askin even though all this is still very helpful. i want to know if i could lets say get a 350 out of a car probably pre 87 and its a carb engine, if i could just take the carb off and go get a throttle body off lets say a suburban tbi and bolt it in were the carb was on the engine or is there more to it than that?? and i would probably get a edelbrock intake and a mild cam along w/ a complete rebuild kit (from crank to freeze plugs). so i know i couldnt use my manifold but from what i hear the stock intakes r no good anyway. now like i said before keep in mind i dont really need much more than 350 hp and not more than 400 ft lbs. due to this being my daily driver and we do get snow in the winter alot. i also dont want the compression to be more than 9 to 1 because i use just regular unleaded so i know i will probably not go w/ 64 cc heads just get the 74 instead and have them shaved and just use domed pistons. i know its not the best recipe but i think it should do if not let me know and i especially need to know about the carb thing...sorry for the length thanx

a throttle body wont bolt in place of a carb without an adapter plate. throttle body's use a 3 bolt triangular pattern and most 2 and 4bbl carbs use 4 bolts

350 hp and 400 ft lbs is ALOT of power for a small block chevy. You will not achieve this power or good reliability with what you are planning. You should be happy with 300+ ft lbs and 250 hp I should think. Its ok, most people over estimate their ratings.

yes this is true but my 305 tbi supposedly has like 190 or 170 hp and is a slug and alot of 350s put out close to 250 stock and i will have a different intake, cam, and headers and the rebuild kit im talkin about...but i was just wonderin about the carb to throttle body injection swap to know how much extra money i would have to spend and how well it would really work.

Justlearning I went down that road... got a 350 crate popped it in but i put the old TBI back on it, but I have a 600CFM holley carb for sale that i need to sell badly :naughty:

How much money do you plan on rebuilding the engine? because you might be better off buying a new one

i dont plan on spending a whole lot probably around 1000-1500 tops and i really want to learn how to do this myself because its somethin that really interests me

and also where would i find one of these carb to tbi adapters i looked in summit and jegs and all they have is two to four barrel carb adapters would i have to look in somewhere like pacific auto

wait, so do you plan on using the orignal camaro engine?

no i have a 305 tbi right now and i want to get and rebuild a 350 preferably a 350 from pre 87 which will most likely be a carb but seem to put out better power than the newer blocks stock and i want to take the carb off and put a throttle body injection on it so that it runs w/ my computer (and different chip of course for the tbi) is that a little bit clearer sorry for the confusion

oh, heh sorry can't help ya there

yeah u actually might be able to more than u think what was involved when u switced from carb back to throttle body cause thats exactly what i intend on doin

I don't know if anyone said it or not, but your plan will work, rebuild a 350 block but use vortec heads, and edelbrock has a vortec tbi manifold to work with those heads, as for computer www.tbichips.com

^what he said

but if you dont wanna go that route, the adapter plate that i'm talking about is actually made for holley's pro-jection kits. it's made to mount a throttle body on to a 4bbl intake manifold. summit and jegs both sell em, i'll try to find the part #.

if i you are planning using a pre-87 350 you better plan on buying a pair of headers. like i said before your, 305 exhaust manifolds will block the dipstick hole, you'll see what i'm talking about when ya go to put it back together. post-87 engines have there advantages: 1-it's a direct bolt in 2-they have factory roller lifters 3-they use a one peice rear seal and oil pan seal. the only disadvantage is that roller camshafts tend to be more expensive, and the stock cam isn't that aggressive. what ever ya decide will work just fine for performance, but you'll encounter some problems if you go with an older engine. i'm just trying to save ya the headaches i encountered the first time i attempted this swap :)

I highly suggest you do not go with TBI. Trust me it will strangle that engine. You will never get decent horsepower out of a 350 with a TBI setup. Carb is the easiest way to go and will give you the best performance. GM 350's have alot of potential but only when they get air. All you have to do to go carb is ditch the computer, and dont worry the computer ONLY runs the fuel injection, so it wont mess anything up. So ditch the computer and you'll need a different distrubuter and a lower capacity fuel pump, because the tbi's run a little more fuel. And if you use some of the 305 parts DONT use the heads, if you do that you will pry end up making less power than the 305. The 305 heads flow HORRIBLY. I suggest vortec or basically anything but the 305 heads. But yea go with carb it will work out the best.

tbi has just as much potential as carb. the only reason the stock throttle body sucks is becuase it's like what 450cfm? you can have the bores milled to 50mm, use an injector spacer and adjust the regulator to make just as much power as a carb and still keep year round driveability.

Holy shit geno, that may have been the most informative post i've ever seen you post.

*sigh* ok, im gonna outline exactly what i mean by my previous posts, this is the bottom dollar way to do this, on the cheap and make it the least cause of a painful headache.

find a post 87 350 at the boneyard. if you can find a K motor CK truck all the better. get the computer, the Throttle Body, and the short block, leave the intake and heads, if you can also find a R code 350, yank the heads and bolt them to your K motor 350, the yard wont know the difference and will only charge you for the single engine. take it home, tear it apart, clean and inspect everything, (you should have done all the junkyard checks, like looking at the condition of the oil, checking for metal shavings in the pan, turning the engine over with a breaker bar to check for smooth turning. to make sure you have a healthy core, also when you yank the heads, check the cylender bores for a ridge at the top, if you cant feel it, or if its barely there and you can see crosshatching on the bores, youre fine, if there is no crosshatching and there is a big lip at the top of the bore, youll need it to be overbored. ) so, with your K motor core, with R code heads, (062castings) and the TB off the K motor, and the computer, head on out. take it home, order the vortec/Tbi intake manifold. now rebuild it, with new piston rings, new bearings, all that. the stock cam will probly give you around 230hp. maybe 250hp, get an aftermarket cam, a mild one, probly a .420-.450 lift cam, and youll make 300hp maybe a hair more no sweat. contact comp cams cam helpline to get better info.

By this point you should have the rebuilt K motor with new cam, vortec heads, intake and 350 Throttle body all assembled and sitting pretty next to the camaro.

now disconnct everything from the 305, take lots of pictures, label everything, and keep everything that you take off in platic bags, believe me its worth the effort. now yank the 305 with all the accesorries and such still attatched. put it on a wooden cradle next to the 350, and swap everything from the 305 to the 350, all the accesories, all the wiring harnesses, al the sensors, yadda yadda, the 350 should now look EXACTLY like the 305 did, just alot cleaner. put it in the car, hook everything back up, bolt everything down, replace the 305 computer with the 350 computer, and fire it up. depending on the cam you put in, you might need to have your chip reburned to work correctly but i wouldnt think so unless you got a big cam.

as far as compression, it works out like this, for the purpose of my calculations, im going to assume you find a good core with good cylenders and wont need the .030 overbore.

cid - 350
cylender volume (cc) - 716.622
combustion chamber (cc) - 61
cylender dish (cc) - 20 (i think thats right, not 100%)
Piston below TOC (cc) - .025in = 5.148
gasket volume (cc) - .045in = 9.267

Total combustion chamber size (cc) - 95.415
compression ratio - 8.5:1

if you use steel shim gaskets, it would change to...

total combustion chamber size (cc) - 89.237
compression ratio - 9.0:1

So with a 9.0:1 ratio, the vortec heads and a low rpm cam, youll be making a shit load of torque at low speeds, have decent midrange power, and better higher rpm power than the 305, and still be able to run 87 octain, maybe even 89 octain gas, ive seen 350's with vortec heads and 9.6:1 compressions running 87 octain.

so hopefully that clears up a few questions, might make a few more though.

holly shit that was everything i needed to know, u dont know how much of a help that will be when i get this money saved up now ill just print all this off and start the savings