SBC to 4.3 V-6:

[Stewart G Griffin]

Has anyone done the SBC to 4.3 V-6 swap, or vice-versa?

[Marc]

Why do you ask?  I suppose you would need the motor mounts, engine, flywheel/flexplate as I think they are externally balanced and fan shroud, to start.  The 4.3 is great on fuel in my little truck and makes good power unloaded but pulling a camper it seems to lack grunt, and it's not a nice sounding or revving engine in my opinion compared to a V8.  It makes good torque pulling away but seems to not like revving much past 3000 rpm.  It's a three speed standard with 3.07 gears.  I'll keep the V6 for now though as I can enjoy driving it without spending a fortune in gas.

[Stewart G Griffin]

Well, the reason why is because i'm contemplating making this change---to the 6 as a long-term goal mainly for economic reasons;  i use the truck mainly for transportation and occasional light hauling/towing.

i get the feeling that everything is pretty much bolt in, yes you may have to get different frame mounts, fan shroud (although i would probably go electric at this point), different hoses, but everything is pretty much bolt in----except maybe the exhaust?


That's pretty much my only real concern----will the 4.3's exhaust manifolds bolt up to the stock v-8 exhaust, or will there need to be some re-working?

[eventhorizon66]

If you gear it correctly and you only ever use your truck for cruising around slowly, then a V6 can get better mileage.  But if you use the truck for hauling heavy stuff with any regularity you will be best served with a 350.  Either way, I'd suggest investing in a 700R4 swap first.

And if fuel mileage is your ultimate goal, might I suggest, as Vile has several times, that you're attempting it with the wrong vehicle.  If you want mileage and an older vehicle to tinker with, what about a Vega, a Nova, or, since you love Pontiac so much, a T1000/Acadian ()?

[1980c10]

Some 4.3 liter engines are externally balanced while the earlier ones are not. if they are you will have a larger flywheel  and it may not fit into the bellhousing. The ideal year would probably be an 85 as it is not externally balanced and came with a 4bbl intake. I had an 85 in my 82 s10 I bored it added a small cam polished the heads and intake a little.  it had about a 9.5:1 compression ratio and a holley 650 dual feed carb and a high volume electric fuel pump with my home-made headers. mated to a 4speed trans mission. don't underestimate the potential of the 4.3 they can be woken up quite well. But then again mine was in a 2500lb vehicle.

[Stewart G Griffin]

What i'm mainly wondering about is, since these v-6's are basically small blocks with 2 cylinders missing(hopefully the front 2), then does this mean that the v-6's exhaust manifolds will bolt right up to the stock pre-existing exhaust system----downpipes?

b) Would the exhaust manifolds bolt up anyways?

[Marc]

I don't know - but you would just grab the y-pipe off of the donor V6 to hook into your exhaust.  The manifolds wouldn't bolt up as the V8 has two more ports on the heads.  What do you want to put the V6 in...a small truck may give you a gain in mileage but a 4WD I would be doubtful.

[Irish_Alley]

i don't think he was talking bout the v8 mans to use on the v6 just he wants to know if the v6 will bolt to the v8s collectors but i guess it just depends on what size they are i don't see v6 and v8 being the same size since the v6 has less to move. also i doubt they are in the same place. in my impala it had the 3800 putting out 240hp 280tq so you can have a peppy v6

[Marc]

I think the collectors would be about the same size.  I would guess they are 2 inch or so.  The 6 in the truck is pretty peppy but it's only a little truck...add an automatic and 4 WD it may be a different story.  The 3800 is a nice engine...I am not sure why they didn't put it in the trucks.  My favourite V6 I have owned so far was the 3300 in a Ciera...peppy and miserly on fuel...the engine was too good for the car.

[zieg85]

I think the collectors would be about the same size.  I would guess they are 2 inch or so.  The 6 in the truck is pretty peppy but it's only a little truck...add an automatic and 4 WD it may be a different story.  The 3800 is a nice engine...I am not sure why they didn't put it in the trucks.  My favourite V6 I have owned so far was the 3300 in a Ciera...peppy and miserly on fuel...the engine was too good for the car.

X2 on the 3.3L  I had one in a 93.  Routinely got over 30 mpg and ran like a raped ape.

[dumbucket1]

I don't know about these trucks but I tried bolting a 305 that came out of a 92 truck to the 4.3 v6 y pipe of another 92 truck that was a v6 and it did not work