Here's the deal.....I have at my disposal a complete TBI system, ignition and computer on a '87 454 in a 1 ton Chevy. My son has an off road Blazer 4x4 project that might get one of our stock '70 455s for that killer Buick torque. The reliability and drivability of the TBI setup would be natural for this application. The performance loss would be negligable I think. Has anyone done this? Thinking back to GN turbo V6s would I have to get a chip burned to zero in the tune? Any thoughts appreciated, Thanks, Steve weim55 Colorado
My opinion is that if it worked well on the stock '87 big chevy, it would be fine on a stock Buick 455. The system would probably wouldn't "know" the difference. Problems arise when you change vacuum levels (aftermarket camshaft) and/or exhaust flow (headers/mufflers), but the system should be able to handle minor variations between the two engines as long as these variables don't drift too far from the original calibration. I don't know if the aftermarket offers (offered) anything to give you more control than just a new chip. I don't remember...is the '87 ECU tied in to ignition timing as well? Just wondering if you'll have to swap over ignition components as well. Devon
how close are the intake runners, would you have to mill out some adapters? If so blueprint it and hang onto it, its a hell of a idea.
TBI not TPI Basically its an EFI carb, it sits on top of a wet flow manifold like a carb it just has the injectors mounted above the throttle bores and sprays the fuel in under pressure rather than has the fuel sucked out by vacuum. Its like the Holley Pro-Jection system. The hard part would be interfacing the timing controls using the electronic HEI distributor that comes on the TBI 454's. I'd also be worried about the EGR or lack there of on the 455 causing you to run lean or too much advance. Most computer control systems who are designed for use with an EGR don't take well to having it removed unless told so. I'd love to see it exicuted as I'd like to do something simular with my nailhead possibly.
Thanks for the input guys, got me thinking here.......... Good call on the EGR. Mabye I could adapt a '73 and up intake to the '70 heads?? As for the distributor, yes it does interface with the injection and computer. All timing input is sent from the computer. I haven't looked at the two side by side yet, but I'm sure it wouldn't be too tough to make a distributor come together. Cut and weld a base to the other housing shaft......or mabye make a computer V6 one work somehow. The stock 454 Chevy actually still uses a Q jet pattern on the intake with a factory TBI base drilled for it. Should be a piece of cake to get 'er on the Buick. This weekend I'll take a closer look at all the components in detail. I haven't looked at the complete system.... sensors, wiring, smog stuff etc. yet. I'll update you with what I find and let you know. Thanks, Steve weim55 Colorado
As for a distributer. You can take a 3.8 computercontroled distributer and press of the 6 cylinder reluctor wheel and take one out of a v8 distributer and press it on, then just use a v8 pickup and module(and make shure you use the 455 cam gear). If you need help i've done this before.
I don't know that you would really have a hard time with the computer if you put headers and diff mufflers on the truck. I have a 92 Chev 1/2 ton with a TBI 350. Two winters ago I freshened up the engine with rebuilt heads, shaved .010", Performer TBI cam, AirResearch 1" spacer under the TBI unit, shorty headers and a Flowmaster muffler. I did wonder if the computer could handle the changes all at once. I know the whole package is pretty close to stock specs at the end of the day but I have absolutely zero driveability issues once it warms up. The only problem at all is cold starts when it's under 40*. Otherwise, there are no problems. No check engine light, nothing. Runs on regular gas with the timing set at 6* advanced. All kinds of low end torque but it falls flat at 4000 RPM. Got 18 mpg driving from Reno to Seattle with a full load of 'stuff' from the move. Use the TBI if you can. Isn't there a computer controlled Buick distributer that needs just a change of cam gear to work in a BBB?
As far as the computer controlled distributor, I don't see why you couldn't just take a stock buick 455 HEI distributor and swap out the 4-pin module for a 7-pin module(the 7-pin is computer controlled). Just make sure you get the polarity of the pick-up correct and it should work. Does the 454 distributor already have the 7-pin module? Oh yea...you'll also have to lock the mechanical and vacuum advance mechanisims. There are different ways to do this. I took a little different route for a computer controlled distributor with the custom EFI 430 setup I'm working on. See the post about it in this section that I'm about to post... See this site for more info related to GM distributors: http://www.megamanual.com/ms2/GM_7pinHEI.htm
I know that this is an old thread, but I did this a while back. Junk yard 455: I used the TBI unit from a 1990 Chevy Suburban 454. Had an aluminum adaptor made. Also used the O2, map, temp sender, from the same application. Hooked up the crank sensor, hooked up to the tack (Buidk HEI), hot side of the coil, positive, ground, I even have a OBD-I hook up that works and a check engine light. Got a computer from a 86 TBI Chevy 350 van. It ran in limp mode until I got a guy in Detroit to burn a custom chip..... He said he could burn one for knock sensor, emissions, cam spec's, ect. This deal was SUPER CHEAP...... and runs great.....
I know TA was offering a complete system like the wet flow system described. You might want to research what they were offering for more ideas. Steve
Rivman, could you please contact me with some help on doing the V-6 7 pin conversion to the V-8 dist? Thank you 71 buick graham
