Rochester TBI throttle body, harness, conversion plate
That's conventional two-barrel to square bore, as 67Dart273 pointed out.
The Rochester TBI is an offset three-bolt pattern, like the picture I included. I believe this three-bolt TBI pattern is shared with Holley Pro-Jection.
Speaking of that Mr. Gasket adapter - that's one hell of a messy looking one-size fits all setup. I wonder how much turbulence those nut adapters create in the transition area.
I think I got the whole TBI, ECU and harness off a 360 TBI truck. Ill never use it. doesnt have a IAC, it used a throttle kicker. Its a Holley for Mopar but looks similiar
360 TBI - that's the '88-91 pre-Magnum unit, right? This is going on an '89 LA 360 with Magnum heads on it, so it's basically what I got rid of.
If it's the stock unit, I'll pass. From what I've read, they're a bit fiddly, and I'd prefer to rely on the Rochester system just because of the amount of knowledge out there about them.
I believe the TBI units are a special pattern
OP--Holley used to make a 2bbl TBI "Pro-jection" I don't know if the Holley bolt up is same as Rochester or not. So the Holley adapter would be to mount a 2bbl Holley TBI unit on either a 2 or 4bbl "standard" American V8 setup
They are a different pattern. Three bolts and offset the same as the Holley 2-barrel Pro-Jection.
Honestly, I wouldn't say no if someone put a complete Pro-Jection system under my nose for dirt cheap, but there's a lot more experience and knowledge out there about the Rochester/GM setup that I can fall back on.
-Kurt
