4.3L tbi on 2.8L motor

[dekoningc]

Was reading a thread on a few cheap ways to put some more grunt in a stock 2.8L s10, im my case a 2wd 88, and read that a gm 4.3 tbi would bolt right up and net around a 20hp gain. Is this true, and if so, what year and vehicle should i be looking for to grab one off of? Also, I plan on getting a throttle body spacer, Airaid from LMC truck to be exact. If i go with the 4.3L tbi, should i buy the spacer for the 2.8L or 4.3L.

Any info would be greatly appreciated.

[dekoningc]

here is the thread should anyone be interested

http://www.s10forums.com/forums/showthread.php?t=2104

[Hard Driver]

If you going to put the 4.3 tbi on the 2.8,use the 2.8 injectors on the 4.3 tbi to keep it from running rich,also instead of the adapter have your intake bore to fit the 4.3 throttle bores.I found that a 4.3 tbi off an Astro or Sarfari has the right linkage bracket and requires no modification.No,it won't give you 20 hp unless you add a cam[260] and free flow catback.

[bobditts]

search feature is your friend.

[dekoningc]

thanks for the info. what year safari/astro vans would work to grab one off of?

[Hard Driver]

Quote: Originally Posted by dekoningc

thanks for the info. what year safari/astro vans would work to grab one off of?

I don't know what years came with the 4.3 without looking it up but just take pic of your 2.8 tbi bracket with cell phone and match it up at the wrecking yard.

[regal7point5]

I got mine off a 91 Astro...and as I understand there were only a few years of the Astro that used this style throttle body.

Let it also be known that it is not as plug and play as everyone says. Unless you get really creative with your existing throttle cable, it will NOT match up to the throttle arm on the Astro TBI. You will have to do some grinding and welding to swap the throttle arms. Not hard to do, but not "bolt on". At the factory, the throttle shaft passes through the arm and is then swaged/pressed. You need to grind the end of the shaft, swap the arms, and weld the 2.8 arm on the 4.3 TBI. Alternatively you could drill and tap the shaft and affix with some hardware.

[dekoningc]

could this be fixed by just getting a 4.3 tbi off a similar year blazer or s10?

[neo71665]

The astro you are looking for does indeed have the same exact lever as the 2.8.


Getting any other 4.3, 5.0, or 5.7 tb will work but does require grinding the old lever off and welding the correct one on.

[Hard Driver]

Quote: Originally Posted by neo71665

The astro you are looking for does indeed have the same exact lever as the 2.8.


Getting any other 4.3, 5.0, or 5.7 tb will work but does require grinding the old lever off and welding the correct one on.

Yes,mine was an exact hookup with no modification.Like I said look the 2.8 over carefully,take a pic with your cell phone and then match it up at the yard.

[dekoningc]

regardless of the arm issue, which it seems can be solved by getting a particular astro/safari tbi,i should have the intake bored regardless correct?

[neo71665]

If you don't have the intake bored the tb won't open all the way.

This guy used to sell a bored intake with a tb modded to work
http://members.shaw.ca/betterthanyou/
You can try emailing him and see what his price is. Saves you the trouble of finding and machining parts.

[dekoningc]

thanks for the suggestion. I emailed him and he does in fact still sell them, with all machine work done, intake manifold and tb for 375 shipped. Im thinking it maybe the way to go.

[regal7point5]

This is somewhat of a thread-jack, but I wanted to post my results, should anyone else be considering this mod.

I got my '91 Astro 4.3 TBI, ground-down/radiused the air horns, stacked gaskets on the 2.8 injector pod, bored intake to 1.7", and installed the Comp 1.6 roller tip rockers. I had to tear it down anyway to replace intake gaskets, valve cover gaskets, and distributor o-ring to get rid of some nasty oil leaks. Might as well have done it, right I also deleted the EGR, AIR, and other clutter...runs much smoother than before and no engine lights...yet.

I will say, DEFINITELY noticed a bit of a power bump. Hard to say any exact HP figures, but certainly pulls harder. Also has much nicer throttle response, though this could be from rebuilding the TBI.

[jimmykicker]

Stacked gaskets?

[regal7point5]

Quote: Originally Posted by jimmykicker

Stacked gaskets?

Yes, by stacking two injector pod gaskets (or however many you need, depending on thickness) you give a little more clearance between the injectors and the top of the throttle body base. It does two things....a little less obstruction for air to enter the throttle bores, and also raises where the spray pattern hits the throttle bores. Supposedly, for better distribution, you want the spray pattern to hit the walls of the throttle bores just above the throttle plates.