NEW DISCOVERIES, PT.1:

[Stewart G Griffin]

First off, i'm overjoyed to recently discover that GM makes and markets virtually a turn-key version(minus carb) of the 4.3 v-6 including distributor and carb manifold.

i want you to take a look at the first picture on the first page of the brochure.  You might have to dial down the size:

http://www.gm.com/experience/technology/gmpowertrain/engines/specialized/industrial/2010_4300_Industrial.pdf

What kind of carb can fit on this manifold?

2) More wonderful news:   The 4 cylinder "nova" engine is, apparently also still being produced---complete with HEI distributor ignition. i had previously believed this engine was discontinued 39 yrs ago after novas stopped having 4 cyl engines.   Yes, i know the last "toyota" nova had a 4, but i'm not talking about that one;  i'm talking about the one that was based off the straight 6.

It's all here:
http://www.gm.com/experience/technology/gmpowertrain/engines/specialized/industrial/industrial_engines.jsp

[eventhorizon66]

That could be a decent engine, but you could score one of those used from a late model C1500 for real cheap.  Why stick with a carb if fuel economy is of prime importance?  I would adapt TBI.

Oh, and I hope you aren't even giving consideration to dropping a 4 cyl in your truck.

[Stewart G Griffin]

1) well my main goals these days are dependability, time to runability, and ease of maintenance.  With MPG following close behind.  Because efi generally takes an excruciating amt of time to get running, i've choosen, in general, and without regret to stick with carbs indefinitely.  Although, yet another even more recent discovery could change all this---see #3 below.

2) RE: the 4 cyl idea--don't knock it---the marine version (even better) makes 143hp AND bolts to any of the common transmissions.   It's not too likely i would use it in the truck, but i think it would be great in cars.

3) Even better!   The marine engines:
http://www.gm.com/experience/technology/gmpowertrain/engines/specialized/marine/marine_engines.jsp

This particular 305 makes 253hp and 302lbs torque;  Now if this doesn't finally convince the 305 haters, i don't know what will;   This is a turn-key engine folks.

[1980c10]

If i were to use a 4.3 L  I would find one from a full size 85-87 (i believe these were the years.) they are a roller block,  2.02 1.94 valves, 9.3 to compression and come with a stock 4 bbl manifold that run awesome with a holly 650. i ran one in my 2wd s10 with a 4 speed trans and it was quick.

[choptop]

Id scratch the 4.3. Ive driven several, and the fuel mileage isnt any better than a V8. Go for the 305. The only problem with a 305 in most eyes is performance. 253 hp is respectable. It all depends on what you use it for. I live in the country, pull trailers, and in the lovely state of Texas we have many roads where 75-80 mph is the legal speed limit. Average is 70 mph. My 305 in my 86 extended cab get me about 20 mpg, which I think is great. It doesnt meet my power needs (ok, wants) but other than that, is very reliable. I have several bigblock trucks at my disposal to get my power fix when needed. The 305 would be a good choice for what you are wanting to do.

[zieg85]

Carb'd 4.3L only came in 86.  85's still had the I-6 4.1L and 87 they had throttle body.  Driving my 4.3L home the 200 miles I was impressed with the way it ran.  Burning the oil and a busted starter mount is the only reason I am going with the 350.  I just could not find a used one being 86 only.

[eventhorizon66]

Carb'd 4.3L only came in 86.  85's still had the I-6 4.1L and 87 they had throttle body.  Driving my 4.3L home the 200 miles I was impressed with the way it ran.  Burning the oil and a busted starter mount is the only reason I am going with the 350.  I just could not find a used one being 86 only.

Both 4.8 I6's and 4.3 V6's were available in 1985 according to my original Chevy truck 1985 brochure.

[HAULIN IT]

My '85 was originally a Q-jet carb sitting on a 4.3     Lorne

[dirtracer81_2]

My 86 last week had a 4.3 with a quadrajunk on top. It really didnt run to bad but it was a farm truck the past 7-8 years my dads had it. Now it has a 350.

[zieg85]

My apologies, I guess I didn't realize they used both I-6 and V-6 in 1985

[Marc]

A fuel injected 305 or 350 would be the best.  Since these trucks came with it, it is a relatively simple swap.  that 3.0 would not make enough power to be safe on the road.  I have a 72 Coronet with a 170 slant 6 in it - around a 90 HP/160 FT-LB engine - the car weighs near 2 tons, will cruise on the flat at 65 MPH, but on any hills is down in second or low right to the floor.  Highway mileage averages about 18 MPG.  The truck would lose any aerodynamic advantage the car would have, and would even be slower.  Perhaps a 6BT would be a better idea.