In case there is any confusion, here is the link to John Gough's post at ITOG about bolting the 4.3 TBI to the 2.8/3.4 manifold:
Here is the text of the post if you don't care to go to the link:
"The problem: The stock 2.8L TBI on my 3.4L was not adequate. After hearing
the Holley ProJection uses a 4.3L TBI base gasket, the wheels in my mind
started turning. I got a 4.3L TBI for only $45 delivered off the 'net
(thanks to my fellow ITOGgers for the website). After a thorough cleaning
with carburator cleaner, I put it on. IT WORKS GREAT!!! No more surge
during the open-loop and it allows my 3.4L to breath to it's full potential.
No high-tech tweeking or anything. It gets to redline and beyond in a hurry.
Best of all....160 HP with a total GM install, not one aftermarket part
(Actually the best part is the 270 bucks I saved with the 4.3L TBI).
I am sure the stock 2.8L V6 would benefit from this larger CFM too.
It was not a direct bolt on, but very close. The four main TBI wires plug
right in. The Throttle Position Sensor (TPS) did not. In 1991, GM changed
the standard TPS style on all of it autos. Therefor the 1992 4.3L TBI I
bought had a different TPS plug-in (but still 3 wires). I simply went to a
local salvage yard and got the male pigtail for the 4.3L TBI. With my trusty
multimeter, I figured out which wire went where. Here is the conversion:
Trooper Black to New Black (Ground)
Trooper Blue to New Blue (Position signal 0-5V)
Trooper Green to New Grey (5.0V source)
Second issue: The accelerator cable linkage. I had to use the shorter S-10
cable bracket that happen to still be on the TBI (thank god). Then I took
the Trooper throttle cable off and ground the end down flatter until it fit
the new style linkage. The 4.3L linkage is a lot different because it kinda
wraps around a pulley thing. I like the throttle "feel" better now. I don't
have cruise control. If you do, good luck.
Thats it...proverbial piece o' cake...$47 and a couple of hours at the most.
Now everybody hurry on over to www.car-part.com
before the cheap 4.3L TBI's
BTW we definitely are not talking about putting a 4.3 manifold on a 2.8, we're talking about bolting a 4.3 TBI to a 2.8 manifold.
And the post that was quoted here about the 3.4 swap/4.3 TBI was a previous one of mine, it's no B.S. Dudes, just what has already been done and known to work. The folks over at ITOG have been very busy!!
Hope this helps clear things up.....ed