F body tbi Q's

[383 240z]

I have an entire L03 305 TBI car. will these electronics fit a 327 or will I max out the injectors? I bought this car as a backup while my rx-7 is getting a new motor and I may just drop these electronics into my z but only if the 327 will work with EFI if not I'll hold out till my 383 is finished!! Keith

[Mike C]

It will probably work. You will have to get a different MAP sensor at minimum from a 350 car like a Caprice. I'd swap chips as well and keep your cam timing less than 210@.050 I think the 350 Caprice motor, the truck motor and the Camaro motor all use the same throttle body.

[strotter]

I'm in the middle of doing this same swap. '89 Firebird 305 TBI on an early 327. I'm starting conservatively, to get the thing running, and will add the goofy stuff later. Use the knock sensor off a 350, which pretty much means you'll need to go roller lifters (which I had planned to do before I read about conventional lifters and knock sensors). I got a "K-kit" from Comp Cams, which includes virtually the entire valvetrain and is designed for older motors. You'll need to be careful to get ponies out of it, as the MAP systems (which includes your TBI) don't respond well to cams with overlap less than 112 degrees. Botches the manifold pressure at idle, therefore confuses the computer, which tries to compensate but can't, all kinds of ugliness. The biggest problem for me BY FAR has been the wiring. I'm modifying the factory harness, but I would suggest you *seriously* consider a Painless wiring harness. Wiring has been a major problem for me, but I sort of like the self-abuse, so it's just me. Painless wiring sets are supposed to be color-accurate, simple, and fairly affordable. You'll be able to use the stock injectors (assuming they're in good shape) at least initially, if you adjust the fuel pressure (which is possible using the factory components). Check

 

http://www.thirdgen.org/techbb/

 

and use their search function. Also check out the "Ultimate TBI Mods" in their tech article section. VERY useful stuff, including how to modify the factory fuel pressure regulator so that it's adjustable (a few psi). Also, get the JTR "TPI and TBI Engine Swapping" book, which is going to tell you not to retrofit F.I. onto an older engine. They're right, but I'm doing it anyway.

 

Something else that you're going to have to take on is the computer. It's not really optional to "chip" even an original motor to get any horsepower out of it, and is pretty much mandatory for a swap of this kind. Remember, a maladjusted carburator will make your engine run rough, a maladjusted fuel injection system will melt your motor to slag. You'll need to find someplace to burn you a custom chip, and hope they get it right, or you'll have to bite the bullet and get a n EEPROM programmer and some software to do it yourself. My take on it is that it can be done straightforwardly, but takes time and trial and error, yet gives a superior result to outsourced custom chips. The whole shebang costs about $200 or so, you provide the computer (ideally a laptop so you can drive around with it hooked under your dash and just *amaze* all your friends.

 

If you have any more questions (and I just bet you will) I'll do my best to answer. Hopefully I'll have the thing fired in the next couple of weeks, so we'll know what does and doesn't work. Good luck.

[Mike C]

The 350 knock sensor is a good tip. You should run hydraulic valve train, but it doesn't have to be roller. I have a 305 TBI motor, wiring and computer from a '90 model 5 speed car if somebody needs parts or a complete motor.

[383 240z]

Any tips you may have I will be great. Keith