Wineman

Have an '89 RS with a dog tired 305 TBI in it. Looking to swap in a 350, and have read every article (I think) on here, about LT1/LS1/TPI/TBI etc. I'm still confused as hell.

What is the most efficient and effective way to swap a 350 for a 305? I have a guy who has a 350 TPI that I can get for what I feel is a fair price. What steps do I need to take, and how can I ensure that this gets done right the 1st time. I am by no means a mechanic, however, do have some technical and mechanical skills. More than likely, I will buy everything I need and have my mechanic (read: Bay/Lift/Hoist) remove and reinstall everything for me - I need to make sure he has everything he needs.

What should I be looking for and what shoud I buy? Any and all help is much appreciated?

V6canvas

iTrader: (1)

Well, in a TBI -> TPI swap, it's going to be relatively straight forward. The in-tank pump will need to be upgraded (tpi uses higher pressure), the harness will need to be modified, not sure on the specifics on that, I believe that you need a different pcm, but I'm not the expert on that. Try to get as much tpi specific parts from the donor car as possible.

Physically it will fit no problem, engine mounts will be fine, exhaust will bolt right up, you'll need a new air filter/ducting setup. There will be a bunch of 'little things' that you'll run into, but far less than if you were swapping to a LTx let a lone an LSx.

eseibel67

I'm going to advise against this. It's definitely something that can be done, but cobbling together a swap with used parts isn't something a pro mechanic would want to take on when he's banging out high profit brake jobs on Hyundais all day long. Every time he runs into a missing piece on your swap he has to push it back outside. Then you have to find the piece before he gets back at it again. And he knows that he's going to own it from the first time he touches it, until he sends you down the road and you stop coming back with "issues". Not sure if he's going to want to go through that much grief unless you are willing to cough up the right amount of dough. These types of swaps are usually better to do on your own, as a hobby, that you can take the time to research.

five7kid

iTrader: (14)

Actually, I'd say get "all" the TPI-specific parts from the donor car.

Turning a TBI harness into a TPI harness is a major pain. Not worth it when you can find an intact used harness relatively easily.

novaderrik

i'd keep the TBI stuff from the 305, swap it onto the 350, and bolt it in... either do it yourself, or help your mechanic friend do it so you learn something... then later on you can tackle swapping it over to a TPI..

Wineman

So, I can keep all of the TBI stuff and bolt it onto a 350 as the intake? What all parts should I plan on keeping etc?

ninetyone

iTrader: (2)

Stick with the TBI. Just swap out the block. Much easier. You will need . 350 TBI knock sensor, ESC module , 65lb cop car injectors and 1989 ANLU prom chip.

ninetyone

iTrader: (2)

+1, get it running right first!

Tuned Performance

iTrader: (92)

If you need assistance with the computer reprograming let me know. the tpi is a better way to go but the expense of the conversion will be more, with wiring, replacing the fuel pump and a tpi setup. Tbi you just need larger injectors a knock sensor and depending on the esc module numbers maybe a esc module and a prom to recalibrate the computer.

https://www.thirdgen.org/forums/engi...ml#post5551096

Wineman

Thank You for making this make a little more sense to me. Now I know what direction to at least head in with this. If I have an 89 305 w/TBI, is there specific 350 block & heads that I would want to acquire? Is one better than the other or ? Assuming I am now keeping the entire TBI setup from this car to bolt on to my new 350?

Tuned Performance

iTrader: (92)

Do you have a budget in mind that your wanting to stick to ?

ninetyone

iTrader: (2)

I would go the vortec route

Wineman

I dont want to say money is no object, but I am wanting to do it "right" so that it is reliable. So, that being said, no, I do not have a budget, but I want to keep it reasonable, while expecting and knowing that good quality will cost a few $$$

Tuned Performance

iTrader: (92)

A vortec build will cost a little more but yield more gain than say a mild build with rebuilt 083 heads. I would look into a long block and do a cam swap.

http://www.jegs.com/i/GM+Performance...FUNgMgod22MAOw

http://www.mabbcomotors.com/catalog/...d_Warranty/932

http://www.jegs.com/i/Chevrolet-Perf...oductId=813788

bwiencek

I would skip the TBI on a TPI engine if you're not mechanically inclinded and are paying hard earned cash for the swap - all the work and you really won't be all that impressed as the heads on those aren't the best flowing and have limited potential...

I would personally do the following:
- Purchase a good used 96-2000 Vortec 5.7L engine
- Pull the intake off of it (and sell it with the spider injection setup - they should net $125ish for a good used one)
- Purchase and install a Vortec compatible intake (cheap import from ebay, a summit one - http://www.summitracing.com/parts/sum-226018/overview/ or an edelbrock 2716 or 7116 if you're going to upgrade cam/exhaust later)
- Purchase a TBI adapter plate (Trans-Dapt 2210, 2202, etc.) and bolt that to the intake then your existing TBI to it.
- Get a set of injectors from a 350 TBI pickup truck (they flow more fuel/hr)

Drop everything into the camaro and either order a "mail order tune" for the setup, learn to burn your own chips, or have someone locally dyno tune it (best IMHO).

You can start/run on a stock 350 TBI calibration but you'll need to get some more fuel into it and adjust timing maps to get the most out of the setup.

The Vortec engine has much better flowing heads, it's equipped with a modern roller camshaft, and being newer should be easier to find in good shape. Stock vortec was rated at 255hp and the TPI engine was rated at 225 - that's an easy 30hp for just buying the right engine up front - plus from what I've seen guys are wanting WAY more for the TPI engines than they do the "old pickup engine" - I've bought good used vortec 5.7's for $500-700 (and can still find them for that price easily)

If you're looking for more performance than a stock 255hp vortec then swap out the camshaft and there are drop-in valvesprings to support 'big' lift cams (or use a vortec friendly lift cam) and free up the exhaust with a good header/cat/exhaust setup.

If you want some real good info on this swap and some real world dyno numbers - head over to the full size chevy forum - the pickup guys swap their TBI 305/350's for vortec 350's using the adapter plates on a carburated intake all the time and get some good power out of them.

Wineman

That is some GREAT info - thank you very much. Been busy with work for the last few weeks, so only real change is swapping in the new rear end...rest is going to have to wait a few more weeks / vacation and some long work days lie ahead, so time is at a premium right now. Looking like early July before I can get back into it and I am surely looking forward to it!! This will give me just the project !!