89formyoula

so i recently bought a 1986 trans am, lg4 5 speed car, t-tops, etc, well...the 305 is literally shooting oil out of the dipstick, its been ragged its whole life, im not going to waste my time with the 305, plan on buying a good running 350...im sure theres a thread about this, if so...send me a link? what has to be changed? can the t5 handle a 350? its carbed so it shouldnt be much, what gears came in the back of these cars? the rpo codes sticker is gone so im kinda stuck, any help would be great!

vetteoz

iTrader: (13)

Straight replacement ;305 is identical block as a 350

89formyoula

What about the ps, alt, etc? What year 350s are setup the same?

89formyoula

and does it matter what side the dipstick is on?

NagleMac

iTrader: (1)

A 350 is just a straight swap. You can reuse all your accesories from the 305 (ps, alt, etc.). The only problem is the carb. I assume you have a Q-jet right now, I'm not too familiar with those carbs but I'm almost positive you'll need a bigger carb (more cfm), the easiest thing would be get a carb setup from a donor car that had a 350. Also it doesn't really matter what side the dipstick is on as long as you have room on either side.

If youre looking for a 350 carb'd setup i think you'll be looking for 82-84(? or possibly 86, im not sure)

vetteoz

iTrader: (13)

Makes no difference.
All you have to do is make sure any SBC you want to swap in has the same bolt holes in the front of the heads that your 305 has
Some early engines have none or not enough holes

At 780CFM on a Q-Jet he won't be wanting anything larger
Q-Jets were used on BBC

NagleMac

iTrader: (1)

Thanks for clearing up the Q-jet info, i dont know too much about what they were used of or the cfm of them.

83C_CamAroZ28

iTrader: (12)

I did the same swap u can use the same carb no problem...

89formyoula

should i get a 350? or send the 305 off to be built? i dont care about originality, i just want a fun street car thats reliable, whoever had it before me put a 600cfm edelbrock on it...id rather have a q-jet.

NagleMac

iTrader: (1)

Your looking at around the same price to rebuild a 305 and 350, so if you want more bang for your buck, go 350.

89formyoula

Thing is most 350s I've found are from the late 70s...would they still make more power stock compared to a a 305 with a cam?

89formyoula

And where is the code on the rear?

Jim85IROC

iTrader: (2)

Your best bang for the buck will be an L31 Vortec 350 from a 96-98 truck. It will require a new 4bbl intake, but it's by far the best used 350 you'll find.

89formyoula

how much do they run for?

cypris09

iTrader: (1)

Also on a side note you could always buy a regular 350 and find a set of vortec heads and throw a cam at it. At the local junk yard they usually go for about 350 bucks not sure on the straight vortec 350s though. I thought there were a sb version and bb version of the q-jets but im not really familiar with them other then my brother had one on his stage 1 455

89formyoula

my 78 trans am has the factory 800cfm qjet..my old 78 camaro had a 750.

Jim85IROC

iTrader: (2)

Call a junk yard in your area and ask for a 350 for a 98 Silverado.

89formyoula

can i run hei on it with no problem? what about the flywheel? and headers?

Jim85IROC

iTrader: (2)

It's all fine. The only difference in using Vortec heads is the need for a new intake manifold. Otherwise it's just another 1 piece RMS roller cam small block.

89formyoula

So when I get headers..just get some for a 350 tpi car? What intake and carb should I run? The car already needs a new clutch...should I just get an stock one?

Jim85IROC

iTrader: (2)

yeah, regular thirdgen headers. Intake and carb choices should be made exactly the same way you would for a non vortec motor, but just make sure you get the vortec version of the intake. Edelbrock, GM, Weiand, whatever. I'm sure something like a Performer RPM or equivalent and a 650 Holley would work well.

89formyoula

will going carb down the power any?

Sojer

Vortec heads can't take much lift stock about .480 max I know a guy that had a TA with that engine and had a zz4 cam in it and killed 2 springs in no time. Zz4 cam has a little over .500 lift

89formyoula

will it break the stock t5? i just need it to last a few months haha

89formyoula

what about a lt4 cam?

89formyoula

Will I have to run an electric fuel pump? What about the distributor? And ignition?

Sojer

If u running carb no, efi yes. I don't know what the LG4 code is, H.O. 305 with q jet I think. But its a carbed car. Just keep it simple, I don't know what u want from it but get any 350 (that's worth buying) if u know how to work on them than put a cam with aroung .480 lift a most stock carb intakes should be good and a carb size about 600 cfm. Get a new clutch while u at it. You will have good clean fun. Vortecs heads are ok but to me not worth the trouble for what they put out. Some stock 113 heads flow about the same but can take more lift and they are lighter. They are the some heads used on the zz4 crate motor and that puts out 355 hp 405 torque.

Kush Barnes

HI, i have a 88 firebird formula 5.0 and i just bought a 350 out of a 99 yukon, the guy told me that it should drop right in, is this true?? if not what would i need?? im pretty sure both of them are injected, im in a crises!! never done a swap before and i have a deadline !!

Sojer

Is your 305 (5.0) TBI or TPI. It will drop right in but its some stuff u will need to buy. A 350 ESC and knock sensor if the 350 don't have one. I'm not sure if the truck intake will fit under the hood and u can't use your old one. Use your oil pan of the 305.

Jk_Under

Look for a 350 vortec block out of a newer Chevy SUV

Jim85IROC

iTrader: (2)

That's the same motor that the entire 2nd half of this threaf is about.

Kush Barnes

um im not sure if its tbi or tpi, where does it say?? ESC ...so new computer and knock sensor, maybe a intake?? i bought this car awhile ago and ive only seen it a few times, busy with music, just pulled her out and trying to get her right.

Sojer

U have to look it up go to 305 to 350 tpi swap

Kush Barnes

ok, what does ESC stand for?? they keep saying electric starter control at auto zone , so will both TBI N TPI engines drop in pretty easy then or is there one i CANT use,will it run smooth with just the esc n sensor