stxbuck

Hi guys,
I have a question and I want your opinion. I bought a 79 T/A it came with the original 403 engine with matching numbers. It needs a total rebuild. I found someone online who has a newly rebuilt 403 engine off of another T/A that comes with headers as well. I am conflicted. Should I continue to rebuild the engine waste ????$$$$ of money or buy a newly rebuilt engine with headers for a really good price ($1300)? A friend of mine tells me just change the engine block where the numbers are at. I really don't know what to do. What do you guys think?

stxbuck

Hi guys,
I have a question and I want your opinion. I bought a 79 T/A it came with the original 403 engine with matching numbers. It needs a total rebuild. I found someone online who has a newly rebuilt 403 engine off of another T/A that comes with headers as well. I am conflicted. Should I continue to rebuild the engine waste ????$$$$ of money or buy a newly rebuilt engine with headers for a really good price ($1300)? A friend of mine tells me just change the engine block where the numbers are at. I really don't know what to do. What do you guys think?

442Harv

If it is a complete motor, you can never rebuild yours for that amount of money. I would buy it and save your old motor, in case you want to rebuild later.

Loaded68W34

Buy the rebuilt engine, put it in the car and stick the original motor in the corner of your garage. Chances are you can't just swap blocks as your friend suggests (if the new motor was taken .030 over, or even finish honed to size for new pistons). If the motor has really been rebuilt, leave well enough alone and at the very most go through it to see the work was done properly. These cars have been bringing more money lately, keeping the original motor in the corner of your garage will ensure you don't put a rod through the side of it or cause any other damage if you decide to go out and drive the car like the bandit. You can always rebuild it later if you choose.

v8al

Agree. If possible before purchasing I'd suggest inspecting the "rebuilt" motor by pulling the oil pan. Also review any receipts for the motor/parts.

4speed455

If your car has a manual transmission make sure the other motor is setup for a pilot bearing.

joe_padavano

403 T/As were all automatics. MT cars came with the Pontiac 400.

fleming442

I'd want to hear the "rebuilt" one run, check oil pressure, and whatnot. Or, considering it's only 1300, just scoop it up, rebuild and inspect it yourself. Check the cam lobes well, too.

Sugar Bear

A "rebuilt" engine comes with a W I D E amount of variables. Are there receipts for the work and parts? Can you hear it run, do a compression test and find out WHY it is being sold if it is that good? And no, don't listen to your friend about changing the #'s.

What is wrong with your engine?

Andy

Buying a rebuilt motor is a gamble unless you can hear it run..you already said it was online sale so that’s probably out of the question. I guessI would ask why 1300 when just the machine work is right around that cost if it was bored, crank turned, heads alone are 800-1300 to be rebuilt..

stxbuck

The guy selling the Rebuilt 403 engine says he took it out of his trans am and sent it to get worked on. Then he sold his roller and after a few months got his engine back and has no need for it. He said it's .30 bored, new gaskets, all new internals. He claims 100% overhaul. My engine is locked, intake is completely rusted, some bolts are missing, oil pan is damaged. Just thinking if it's worth saving and how much money I have to put invest in it to get it running.

Sugar Bear

Sounds like yours would be $$$ to rebuild. If your car is really nice and you have the room, put oil in your cylinders and the intake, pull the matching #'s engine and store it. Look at the engine for sale but the owner should have receipts to back up the claims or tell you where it was done and you could talk to the builder. Pull spark plugs on it and look in the cylinders, they should be spotless with ZERO corrosion.

If you live in a cold climate and yours got water in it there may be cracks. Ask a ton of questions here, our experience is very diverse with some members actively building these engines. You are at the correct place.

Good luck!!!

fleming442

Some very good points made as well. If you can't witness it run and the seller can't provide receipts, it's a $500 core. "All new internals" is a red flag at that price, unless those "internals" are rings and bearings.

Olds64

If you swapped to a new engine what would you do with the one in your car now? It's my understanding that T/A owners prefer the Pontiac 400 over the Olds 403.

stxbuck

Just a quick update. I took everyone's advice asked the seller for receipts and/or to speak to the people that worked on his 403 and he flaked. He said no don't worry someone else is interested. He took offense to it. Either he was lying and it wasn't what he said he was or he got his feelings hurt. Either way thank you everyone. Today we brought home our original 403, it's already on the engine stand.

matt69olds

Sounds like you dodged a bullet. If I was selling something, I certainly wouldn’t be pissy if someone asked questions.

Sounds like the guy was trying to pass off a spray can ring and bearing overhaul for far more than. It’s worth.

Koda

Yeah, that dude's a bitch. Stay clear.

Waverly1984

Make the swap. Keep the original engine in storage.