Need a key on 12V source:

[Georgeb]

Somthing like this with some silicone to seal it up if you wish.

 

[87scotty]

This is what i have done as well.

i think i am going to just jumper the plug that fits over this sensor. The fact that the choke is going to be engergized while i'm cranking the engine is of little concern to me because it doesn't get THAT cold here and the engine starts pretty quickly anyways even with no choke. So those few seconds really aren't going to make a big difference.

Whays wrong with choke being powered while cranking no diffrent than any small engine correct?

 

[fussfeld]

Whays wrong with choke being powered while cranking no diffrent than any small engine correct?

i think some people are concerned that if they have to spend a considerable amount of time cranking until the engine starts that the choke will open a little too much? Because if it's wired to key on power, then while the engine is cranking, the choke is receiving power?

In my case, my engine starts pretty quickly anyways, so those 1 or 2 seconds that the choke IS energized before the engine catches makes little difference to me.

 

[fussfeld]

Somthing like this with some silicone to seal it up if you wish.

Got it.

 

[fussfeld]

So anyways, to go off topic here are other differences between the 4.3 and v-8 small blocks:

Also, i will prestate that mine did not come with oilpan, valve covers, timing cover. i don't know if the newer, balance shaft 4.3 crates come with these. i would have to research that.

1) Obviously the oil pans are different; These are not easy, at least it was not for me, to find these. So i decided to re-use mine off the first used 4.3. This required cleaning which meant putting it in the oven (one advantage to the 4.3 pan is it can fit more easily in an oven) then spraying it with ez-off. But then this took some of the paint off, so i had to repaint it. i also had to research the different types of pan gaskets---2 piece vs. 1 piece. i think all 4.3's 86 and after use 1 piece. Then also had to research the sealant needed at all 4 corners.
ALSO NO corner studs or pan bolts included. i reused my old ones.

2) It did not come with an oil pump. These are the same as a v-8 but i had never installed one. So, i had to research how to set the height of the pickup---which required a special tool which i had to research, order and wait for it to come. Also, i had never done the thing with the nylon collar. It took me a while to figure that out.

3) No valve covers and these are obviously shorter than a v-8 AND they are not easy to find even in the aftermarket. So, again i decided to reuse the ones i had. You would think that this is a fairly popular engine (and it is) so i was surprised that i had to drive clear across the city because only a few stores had the gaskets in stock. This was about 50 miles roundtrip.

4) Timing cover. Same as v-8, BUT not really----the 4.3 uses a different harmonic balancer than v-8's It's much smaller in diameter, SO THE TIMING TAB is in a different position than on an 8 cylinder timing cover even though the timing covers are exactly the same. i had to use my old balancer as well coz these are not easy to find either. With v-8's they are practically growing on trees. And because i had to use my old balancer i had to research what tool to get and wait for it as well as how to install it.

So after researching how to put different timing tabs on i decided to just re-use my old one----this of course meant i had to put it in the oven, spray with EZ-OFF which again took some paint off and which meant i had to repaint it.

Also, guess what? No locating dowells included for the timing cover. So then had to research, order, and wait for these to arrive, then install.


After about 2 months i get to:

4) The distributor. And try finding a distributor for a 4.3...........
i used my old one.
i had to switch distributor gears because my crate/all 4.3 crates come with roller cams. This basically illustrates the differences between 4.3 crates and the basic crate 350 because some crate v8's also come with roller cams.

Had to research, order, and wait for the new distributor gear to arrive. Roller cams require a mellonized distributor gear.

i could not get the pin out of the distributor gear, so i had to go to Horror Freight and get a press. After i got the press the pin came out and back in easy.

5) Oil filter adapter: Totally different from a v8 and i have no idea why. After more exhaustive research, i decided to just use the old one. Requires a special hex wrench.

6) Engine mount towers:
Trucks before 85 never had the 90 degree v-6. The v-6 uses different engine towers than an 8. Well, guess what? Nobody likes this engine, therefore the after market doesn't either and thus they are not going to offer any after market engine mount towers.

At the same time i was researching custom universal type engine mounting systems---the type that can be used to install a small block into almost any chassis. i also tried searching salvage yards. Fortunately someone at the other 73-87 site had some from a previous project and sold them to me cheap.

i had to drill 3 holes on each framerail (all trucks 85 and after should have these pre-drilled). This was actually one of the easiest parts of the swap compared to everything else!

7) if you use a used or reman 4.3 with mechanical fuel pump, it's upside down compared to an 8. The v-6 and 8 fuel pumps won't interchange because the 8's have an oil weep hole on top. i think they put it upside down this so it would clear the front crossmember---other cars such as camaro, monte carlo, malibu, impala also had the 4.3 engine. No crate 4.3's have provisions for a mechanical pump, so in this case you have to go electric. More on that in another thread.


8) This has more to do with chassis than engines, but a v-8 exhaust WILL NOT work with a 4.3 in a 73-87 truck. It's close, but not quite the same.
So i had to get a new Y-pipe. i still have not gotten around to bringing it to an exhaust shop. The exhaust i have now is flexpipe and muffler after the y-pipe.

Now, i THINK but am not 100% sure that with trucks 88 and after the 4.3 and v-8 exhaust ARE interchangeable. This is according to the Walker exhaust catalog.


The whole swap took 4 months to complete! This was working on it in the evenings and on weekends only. i mean, now that it's running good i'm happy with it and will probably stick with 4.3 engines. But if i had just swapped in another v-8 i could have probably had the truck running in less than a weekend and possibly less than a day

 

[fussfeld]

So anyways, i did end up jumpering the 2 prong plug and everything works great.

Now, would anyone know where i can get the little white plastic plug thing that plugs into the choke coil. Mine either broke and fell off or just fell off. The metal clip from the power wire that connects to the choke coil is still intact, but the plastic "cover" isn't there.

i feel that it will be more secure with this plug thing.

 

[Rusty Nail]

Napa.