92 tbi 350 rebuild or repower ?

[Kudzupatch]

I have been digging into this as I am going to be replacing mine in the near future. My conclusion is, it is cheaper in the long run to buy a GM crate motor with a warranty then build one yourself. A quick run of the numbers in my area, with the machine work the cost is about even. And there is no warranty on my work.

If you are going to change anything in the engine, you need to change the 'tune'. I am going to put in the latter model Vortec and that by all means requires a tune to match the engine. Lots of horror stories of people builind engines with Vortec heads, cams, etc and they run worse than before but they are trying to run the stock tune on a modified engine. Typically they are trying to tune an engine by mail order because no one here is working with the OBD1 anymore. I had about decided to just buy a stock replacement engine.

Then I discovered Moates Ostrich, it replaces the chip in the computer and can be connected to most software and tuned like the new computers. Any tuner, if they are willing, could tune it for you. The idea is once it is right, you get someone to burn you a chip and replace the Ostrich, but many just keep in place.

This is the way I am going go. I will buying an Ostrich and a crate Vortec and use my TBI. If I have too, I will tune it myself but hoping to get one of the local guys to do it for me.

[rickpilgrim]

Ok, straight wt 40 oil improved it to 35-38 psi warm hwy and 12-15 at idle so I know the tbi 350 is warn out. No surprise to me, it came without an air cleaner and very filthy oil but again, $500 1992-K2500 truck with an 10 month old/367x. mi goodwrench trans work order that started and ran out strong that was ok.
When I was talking about rebuilding the 95 parts truck 350 and putting in a cam I was thing mild RV type cam to help bottom end power a bit. No stroker, aftermarket heads or street/strip cam.
I have a good 98 vortec 5.7 4 bolt main in a bad frame/trans plow truck. Ideal would be to take that engine and the gmpp intake/egr valve and piping and exhaust to muffler and put it in the 92. I can see more fuel pressure but do I really need a re flashed ecm and everything else for a box stock vortec 350 to run with tbi?

[Kudzupatch]

Originally Posted by rickpilgrim

I have a good 98 vortec 5.7......but do I really need a re flashed ecm and everything else for a box stock vortec 350 to run with tbi?

Yes. Vortec will has much better flowing heads, some of the best stock Chevy heads and a different cam. Your existing TBI is tuned to match a very different engine.

You have to remember that the computers are tuned very specifically to the needs of the motor that is in the car. Change anything that changes air flow or fuel flow and it changes the requirements of timing and fuel. Going to Vortec heads is not a small adjustment, it is major improvement.