Small block to big block TBI

[bstack]

I have an 87 1/2 ton, 305ci in my 4x4 that is going south and have a 454 big block that I might put in its place. The question? Did the big blocks of that era have the TBI or were they all carburated? Just wondering what I would have to do to put the big block in. I also have an older 350 that I could throw in if its too much of a hassle to go big block with that set-up? I'm sure someone has had this dilema before?

[rfmaster]

Hey Bstack

In 87, C30 was available with 454 TBI.
You have to check your local smog laws, but I think a straight over swap should be OK provided that you keep all smog equipment operation per mfg specs ( it is in Cali). Save all smog labels from donor truck! It would be a good idea to have a complete donor 454 TBI with ECM and sensors to swap over.
You can probably re-use your 305 ECM - (my guess it is 1227747), but only if you replace MEMCAL to match 454 requirements, as well as resistor pack for a ‘limp back’ mode. This will require some soldering inside your 305 ECM
ESC and knock sensor are different for 454. Check your fuel pump, and better replace it with a high volume unit (Walbaro, etc).
305 TBI injectors are too small for 454 CID application, also 454 TBI body uses 51mm throttle body (2") diameter. Small block TBI is smaller.

[bstack]

Thanks for the reply rfmaster. I'm kinda ignorant of TBI talk, what is the ECM and memcal? Thanks again

[tommy knotts]

i have a running 87 suburban auto with a bb tbi that i am going to part out,make me an offer on the tbi stuff, wiring, computer.im about 3.5 hours from you in wv.

[rfmaster]

Bstac

If you are going to do TBI 454 swap I would strongly suggest to get 'very' familiar with TBI system. A good backgrounder can be found here:

http://www.binderbulletin.org/forums...ad.php?t=45292

ECM-engine control module
ESC-electronic spark control.
MEMCAL-Memory Calibration Unit contains engine specific calibration information.

[bstack]

Tommy, PM Sent