406-IROC

Hey guys, just got my hands on yet another project, 1988 Trans Am, with a 305 TBI. The car, in a whole, is in pretty decent shape (high mileage though).... and come this weekend, the tired 305 is getting yanked out in favor for a 455 Poncho.

The Poncho engine, as well as 'another' 700R4 that I had lying around, both have a great deal of work done to them (even had a knock sensor thread drilled into the block).... as well as the rear, suspension etc.

Right now, we're still contemplating the fuel system though. With the right intank fuel pump, the right throttle body (and adapter, of course), and utilizing an entire 454 TBI ECM system (which I'm already in the midst of getting).... this could very well work.

Of course, the right chip needs to be burned, and we have to somehow 'mesh' the computer controlled distributor to the Poncho's. But regardless, we're looking forward to the challenge though.

Any thoughts, and suggestions would be greatly appreciated....

(But please remember, were on a tight budget from here on out.... and can't afford an aftermarket EFI system. Not now, anyways)

dimented24x7

iTrader: (2)

The 454 tbi + 90 something pound per hour injectors should feed it ok. What are the specs? If your planning on a combo that makes power at higher rpms youll have problems with supplying enough fuel without some modifications like a vacuum referenced fuel pressure regulator and high pressure fuel pump although either way a good fuel pump should be used in place of the lame stock one.

You could also jsut use a standard dist. and use the tbi for fuel only. Not having to deal with timing would cut your tuning work in more then half. I know some people are using or have used tbi with a non-CC HEI dist. Dont know what needs to be done, though.

You definatly want to do your own tuning. www.moates.net has the basic hardware youll need. You want the flash and burn, 'G2' adapter, zif socket, and chips. This will cost about 130 bucks. I see that your on a budget but youll be dead in the water without it. The 'over the counter' chips are useless. Youll also need one of the freeware tuners and an ECU file for the 7747 or the 8746 ecm, depending on which one you decide to use. The ecu can be downloaded but you may want to ask around as to which are the better ones as theyre compiled by people and just uploaded, so there may be errors. I use TunerCATS (costs money) and I have to write my own definition files so I dont have much experience with the ECUs that are floating around.

Go over to the DIY-Prom board and have a look at the stickies. They give a pretty good rundown of the things youll need to know.

The actual installation should be relatively straight forward but the tuning aspects of EFI can be somewhat convoluted compared to a carb.

1981TTA

I haven't had the pleasure of working much with the 455. But, with the number of Pontiac engine parts that are common among different displacements, there might be an easy "fix" for your CC distributor issue. 301's came with computer control in the early 80's. If the distributors are the same across Pontiac blocks, this might be an easy way to get your timing problem solved......

406-IROC

Hey guys, thanks for you're responses!

The 455 sports an earlier 428 crank. I got pretty lucky with the heads, as I traded a posi-rear that I had lying around for a set of Edelbrock aluminum heads and manifold (both used), which have since received an extensive amount of additional work. The cam is a Competition Cams, Ram Air IV grind. Peak horsepower and torque should come in at around 5000RPM (with the right fuel and air distribution, of course)....

We haven't even had a chance to research the distributor problem like we had planned to this week.... but as of today, the 305 is out, and the 455 is on it's way in. I feel like a freaking kid in a candy store for crying out loud lol!

The exhaust is another issue, but from what I'm being told.... exhaust manifolds will be fine (and cheaper), and the local muffler shop already agreed to fabbing up a Y-pipe, leading to the stock converter.

Everything else is pretty much covered, other than the fuel system. Once the 455 is in, the rear will be dropped, and the tank removed.... in favor for a higher volume fuel pump. I would really like for the distributor to be apart of the computer system, as other than the fatter block, I want this to look very stock (to the unknowing eye).

I'll try to get some pictures up for those who would like to see...

Thanks again guys!

KrisW

iTrader: (5)

Use any pontiac HEI distributor, but 80-82 301,265 already have vacuum advance removed. Use 7 pin module (Jeg's sells a good house brand that can take high rpm) and wiring. You'll have a 4 pin harness plug coming out to hook to your computer harness. Its a small matter to hook up. Get a Chilton's total car care manual for an 82-92 firebird and it has the wiring schematic for both distributors. I did the same thing with an Olds Motor and it worked fine. You don't have to run a remote mount coil. I even used a connector from an 81 or newer olds 307 distributor and spliced it to the factory dual coil connector.