what do you guys suggest for the fuel lines whaen i swap from the tbi to the tpi?

 

You will need to swap the old fuel lines for the TPI fuel lines. They are a lot shorter. You can order them or go to an auto parts store and pick them up. Don't forget to change the in tank fuel pump also, or you won't be going anywhere.

 

You can keep your return line as they are the same TBI and TPI, just be sure to use new correct sized O rings. You will need the high pressure inlet line from the chassis hard line to the hard lines just off the fuel rail. You won't be able to find this at the parts store unless the can make high pressure lines. GM claims this is discontinued but I was able to scrounge up a new one through a vintage parts source used by my local Pontiac dealer. When I bought mine there were around 10 nationwide including mine. I already had a used set when I got the new one so if you want them let me know. Being that your car is an '89 you may have to replace the line from the tank to the chassis hard line but I'm not sure, I didn't have to but mine's a '90 and there could be a difference. Another option is a company called Pure Choice. They offer hose kits for just about every system you could imagine in just about any length and there braided stainless steel with all the adapters. Buddy of mine used them on his IROC when he detailed his engine bay and they look killer. Do the job in a weekend? Maybe if you have help, absolutely everything you'll need and absolutely nothing goes wrong. Mine was done over the course of 4 weekends but I took my time with the details and such and then there's tuning and getting it running properly.