Hey guys, I just joined, and I'm looking for some advice. I recently bought an '87 TA with a 305TPI. I want to swap it out for a 350TPI, but I'm not sure WHAT exactly I'll need. I figure I can buy a built 350 Long Block, and put my intake manifold and TPI stuff off the 305 on it. But if so, I have NO IDEA what years of 350 will work, or if the heads matter... and on and on. I need to know what the 350 has to be (if anything), for my 305's TPI stuff to work with it. I'm looking to get 350HP (ideally) out of a 350TPI with headers, and dual exhaust. So in addition to the first question, any information on how realistic a goal that is, and/or how to accomplish it with the least $$$ would be GREAT, I can spend some money, I'm willing to spend around $2,000ish total on the engine and exhaust, and i'm doing the exhaust myself. Thanks!

 

To begin with a great big welcome to the Thridgen website as this is your first post. Here you will find everything about you need to know about TPI engines including what you are contemplating. Do check out the technical articles on the home page and the suppliers of parts such as Hawks, TPI Parts and others.

As this is your first post here you can be given a pass for not searching this topic, which has been asked and answer several recent times. Do learn how to use the search function it will provide you with a wealth of TPI information. The search function is your friend.

Recently, I asked a question about this conversion which can be found in this thread:

https://www.thirdgen.org/forums/tpi/...litre-5-a.html

Another good source of information on this topic is found here:

http://tpiparts.net/305_tpi_to_350_tpi_conversion

If you do some searching on this board by the key words 305 to 350 or 5.0 liter to 5.7 liter you will find more information on specific procedures of this conversion.

You did not mention if you had a manual or automatic transmission.

If you are just going to swap over the 1987 TPI to a 350 there should not be a lot of issues about which year engine to use (i.e. 1987 to 1991) except what I have noted below. Someone else may be able to provide more issues about using other year engines.

When getting a long block look for the engine without the swirl port heads. If you search you can find which casting numbers for the 350 head to look for or someone may be able to advise you. I only know the 305 ones to look for off hand. If it is in your budget now is surely the time to consider better heads. However, the non swirl port heads are not bad.

A few years ago I replaced my 305 with a new 305 from my local GM dealership. If I had found this website at that time I may have gone to a 350 as you are contemplating. You may want to go down to your local GM dealership with your VIN and price out new or rebuilt engines for your year or the years you are considering. Consider the price of long vs. short block and heads at this time.

Make sure you consider a cam at this time. One of the years of the TPI engines came with a lesser cam. Try to avoid that. Check out the Camaro or Firebird Technical Data page off the home page. If you do consider going to an aftermarket cam search this topic as it has probably been asked and answered many times.

There are lots of header options out there to choose from price being a big factor as well as what to you are trying to address in the way of HP or Torque. While I think it has been done dual exhaust is generally not done. You would want to consider going to a 3” exhaust system. You can find more about that over on the exhaust board.

Also, now will be the time to consider vacuum leaks in the fuel induction system, porting the plenum, runners and intake manifold, bigger runners and intake manifold, new fuel injectors, an adjustable fuel pressure regulator and new sensor. You are going to need bigger fuel injectors for the 350 engine. The fuel injectors of choice here are the Ford Motor Racing injectors. They are cheap and good.

Here is a good article to read on these engines. There are lots of other good articles out there on TPI engines.

http://www.fuelinjection.com/portinj.html

You are probably going to need a custom PROM burnt for this conversion due to the bigger fuel injectors and the installation of a cam, headers and possibly heads.

Hope this helps.

 

Followed by;

For two thousand dollars, you can get your 305 to that level, if that's all your looking for....