4.3 V6 swap

[Racer2172]

I picked up a complete running 4.3 V6 and 5 speed transmission. I am contemplating putting the motor and transmission into my 65 C-10. has anyone done this? Any thoughts or ideas? I have two good straight 250 straight sixes with the good old 4 speeds. But thinking something a little more modern with the overdrive transmission.

[kieth]

It has been done but most go the v8 5 speed route since it costs so little to do. The 4.3 will do a fine job and probably get good fuel mileage. make sure you know how the transmission, rear axle ratio, and tire sizes will play together before changing everything out. I can send you a spread sheet that will show torque to the ground for your current truck and then send it set up for your new engine trans set up so you will know how it will perform before you make the change. send me the following info and I will send you the performance information.

1. current engine

2. new engine info (hp, at what rpm) peak torque and rpm

3. transmission od ratio

4. rear axle ratio

5. height in inches from the ground to the top of the rear tire

pm me on this board and give me your email address.....thanks, Kieth

[61_FL_Apache]

That 4.3 is an awesome choice!! I have many trucks and vans with that engine. Plenty of torque and power..

Sorry I cant help with the install, but good choice on the engine.

[LT1 Burb]

Originally Posted by 61_FL_Apache

That 4.3 is an awesome choice!! I have many trucks and vans with that engine. Plenty of torque and power..

Sorry I cant help with the install, but good choice on the engine.

I disagree, the 4.3 is a dog and gets terrible fuel mileage compared to a v-8. I just can't see doing this swap for any reason, a 5.3 with a 4L60E is a much better choice.

[61_FL_Apache]

Originally Posted by LT1 Burb

I disagree, the 4.3 is a dog and gets terrible fuel mileage compared to a v-8. I just can't see doing this swap for any reason, a 5.3 with a 4L60E is a much better choice.

Man that hurt!! You are right! There is no replacement for displacement!! Im no engine expert by any means, but I have had great luck with 3 different vehicles with this engine. Thats all I was stating.

[Trsmotrhed]

Originally Posted by LT1 Burb

I disagree, the 4.3 is a dog and gets terrible fuel mileage compared to a v-8. I just can't see doing this swap for any reason, a 5.3 with a 4L60E is a much better choice.

I agree, I'd go with a V8 fuel injected with OD tranny. You'd spend the same on swapping the V6 add the V8 as far as harness and fuel lines. That's where the money is at, is in the fuel set up that most forget about.
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[theastronaut]

I gotta agree with LT1 Burb. We have a '97 S10 SS with the W code 4.3 (10 extra hp) and 5 speed and while it has decent torque, it still doesn't feel adequate at times when passing at highway speeds (55+). Your truck is probably around 600 pounds heavier than a S10 too, making acceleration and fuel mileage that much worse. For what a good used 4.8 or 5.3 cost it's not worth swapping in the V6. Even a 4.8 has another ~100 hp over a 4.3. Our S10 gets about 18-19 mpg city/hwy average. With an overdrive trans theres no reason a 4.8/5.3 couldn't do that good or better.

[joedoh]

Originally Posted by theastronaut

Your truck is probably around 600 pounds heavier than a S10 too

most of the weight in the old trucks is in the frame and big iron engines. most of the weight of the s10 is in crash protection and insulation and systems.

I am on the fence about buying a 4.3 auto s10 this weekend and a 49 ford with which to plop on it. My avatar truck is a 2.2l 5spd truck and it will never be a race truck but it works great especially on the highway, 70+mph and cruisin. just depends on what your expectations are. always somebody faster, I like cruisin.


EDIT: Not going to bump an unpopular thread but I am not on the fence any longer. 1999 4.3 auto tilt cruise air longbed



I cant believe people say the 4.3 is underpowered. This has plenty of power, passing, pulling, its all very nice. Just need the 48-52 f1 to plop on the drivetrain now. My first tank was 23 mpg combined. I just did an 'italian tuneup', a gallon of xylene mixed with 3 oz of two stroke oil in a 1/4 tank of gas and drove the crap out of it for 2 hours. Runs SO much better.

[jayoldschool]

I'll plus one what LT1burb said. The 4.3 just does not offer enough fuel economy savings over an 8.

[FetchMeAPepsi]

You guys that say "no way" are forgetting that he already owns the 4.3. He'd have to buy the V8 so yeah, the savings are in the fact that one is in hand vs having to buy a new engine/tranny entirely.

Put it in there, drive the wheels off of it, and enjoy. Just another iteration of these great old trucks.

[LT1 Burb]

Originally Posted by FetchMeAPepsi

You guys that say "no way" are forgetting that he already owns the 4.3. He'd have to buy the V8 so yeah, the savings are in the fact that one is in hand vs having to buy a new engine/tranny entirely.

Put it in there, drive the wheels off of it, and enjoy. Just another iteration of these great old trucks.

Its not even worth doing the swap if someone gave you a free motor and tranny. It is a big waste of time to spend all that money doing all the electrics and fuel systems to end up with something you will hate. I wouldn't do it if a motor was dropped on my doorstep and my truck had a blown 6 in it.

[theastronaut]

I had a friend offer me a good running 4.8, 4L60E, and stand alone harness/retuned ECU for $700 bucks. I think he ended up listing it on Craigslist for 1200 after I passed. Not sure what he actually sold it for. The cost of the swap would increase the resale value by atleast as much as it cost you, in my opinion.
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[Racer2172]

Thanks everyone for the input, think I will have the 4.3 sold this weekend for more than I have in the entire parts truck. Once its out and gone hopefully rest of the truck will go to scrap for a few more dollars, also snagged a good 40/60 bench seat out the truck and steering wheel and will save more miscellaneous parts, now to decide whether to install the 5 speed behind one of the 250 I6 in the garage. Trying to keep costs down on this build. Otherwise would love to drop in a 4.8 or 5.3 love those motors my DD has the 5.3 love it.
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[72step]

I drive a blazer at work with the 4.3 and I hate it with a passion. It is under powered bigtime and does horrible mpgs. It also likes to run on the hot side during summer.
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[61K10]

funny--i had a early 90's 1500/c10 with the 4.3 and a 700r and 3.07 rear gears. yes it was a dog for sure, but on the hwy it got 25 mpg.