sotodn1

Ive read several other threads about the 305 to 350 swap, but I was wondering what the opinion is on which is easier and more cost affective. When I swap a 350 in, should I use a carburetor or keep the TPI system? I am trying to figure out which is cheaper, because I am working on a limited budget.

zraffz

If you switch to carb you need an intake, carb, air cleaner, throttle bracket, fuel regulator. I'd keep it tpi cause it can probably be done for the price of injectors.

sotodn1

Yeah that is true, I didn't consider that, for the price of 8 injectors it would cost the same if not more for a carb set up not to mention more work.

Guest

Don't go carbed. Dinosaurs are dead for a reason.

sotodn1

Ha ha ha, I hear you guys, so I'm guessing the verdict is in...better to leave the TPI on

zraffz

Unless you are actually building a motor the stock tpi setup is better. Once you start doing more serious mods the field levels out.

sotodn1

I found a guy who's selling me a short block and heads, no intake though, but I guess it would be alot easier to use the TPI because its what I already have, might as well use it.

NagleMac

iTrader: (1)

False. All nascar engines ran carbs until just this year, and theres a reason for that. A big reason companies like GM and Ford started switching to fuel injection was MPG. While fuel injection is more precise with gas use, you'll never have an engine thats starved of gas with a well tuned carb. Money wise, you'll be spending less in the long run with tpi, but you will NEVER make more power (or a least consistent power from off idle-WOT) with a tpi setup than a car setup. Carburetors are not dead and i cant see them being obsolete anytime soon. Aftermarket companies produce WAY more new models of carbs than they do fuel injection.

I'm sure you'll say "if nascar switched why shouldn't i?". Well you probably can't afford that sh*t.

sofakingdom

iTrader: (1)

What NASCAR does is not relevant to the issue at hand. Don't let that enter into consideration, it is not a factor here.

While I am not a fan of TPI at all, I would not advocate switching to carb. Especially not when cost is an issue.

TPI itself is identical between the 305 and 350; same plenum, runners, TB, lines, sensors (mostly), etc. All you need in order to switch to a 350, is the right injectors (22 lb/hr instead of 19), a chip, a knock sensor (which you'll probably find you'll have to buy one of those anyway, just ask for a 350 one instead of a 305 one), and maybe the ESC module. FAR FAR FAR FAR cheeeeeeeeper and eeeeeeeeeeeeezyer to do that, than to swap to carb.

NagleMac

iTrader: (1)

You're right, I'm sorry to the original poster if i lead you the wrong way. For you i would recommend staying TPI, its better financially and much less work. My post was pointed strictly towards the person who said that carbs are dead.

He's right with the parts list, it's a pretty straight forward swap and not real expensive.

Tuned Performance

iTrader: (92)

Another vote for Tpi, If you end up needing reprograming for the swap let me know. South Bay has the bosch 22#hr injectors for a great deal.

sotodn1

Thanks alot guy, I think In the interest of money I will stick with the TPI

sotodn1

I do hear however that if the vehicle has a MAF that the 305 ECM can be used with no issue. Doubt that is true however.

sofakingdom

iTrader: (1)

Yes it is true.

They are the same in 305 and 350 cars.

All they do, is to literally COUNT the air molecules passing through. (since as you will no doubt recall from your physics classes, that what "mass" is... how much of something you've got) Air has the same mass whether being ingested by a 305 or by a 350.

Just like the coolant temp sensor is the same... degrees are degrees, regardless of CID; and so on, for all the other sensors except the knock sensor. Reason that one is different, is because it's basically a microphone that's tuned to the specific "pitch" produced by a given bore size; so they're different between a 305 and a 350, not so much because of 305 vs 350, but because of 3.736" vs 4.000".

sotodn1

I do believe that the Prom must be changed though?

Tuned Performance

iTrader: (92)

The memcal can be reprogramed, but like sofakingdom stated you will need to get a new knock sensor and depending on the esc module part number or letters on the module it may or may not need replacing. You will also need 22#hr injectors instead of your 19#hr.


16126761 (ANRZ) is discontinued. Replaced with HKR for the 4.3l & 5.7L engines, and HKM for the 5.0l engines.
16022621 (BLH), is for 2.8l, 5.0l, and 5.7l engines.

sotodn1

Yeah I thought I read about that on here, what I was hoping on doing was using injectors and prom from a scrapped third gen that had a 350 with TPI

Tuned Performance

iTrader: (92)

With the amount of effort involved to replace the injectors I would stay away from Multecs . You never know what your going to get from a bone yard.

Redchevy808

Keep the tpi, I switched to carb and its great, but now my speedometer and torque converter lockup don't work.

sotodn1

Yeah I'm gonna keep the TPI, everything from the 305 should bolt up to the 350 I have. Got a decent deal from craigslist, got a short block with casting # 3970010 and heads and the guy even threw In an extra cam and a set of lifters all for $140.

Tuned Performance

iTrader: (92)

you never stated what year your car is or what transmission you are using but the 3970010 is a two piece rear main seal engine. If the lifters the guy threw in are use throw them away or you will wipe a cam.

sotodn1

Sorry bud, my car is an 86 Iroc-z with a 700r4. Not sure what I'm gonna do with the cam and lifters, they look brand new. Hopefully get some pictures up of what I'm working on.