4.3 Vortec swap?

[dogsht]

Both engines optimized with the right carb, timing, intake, cam, gear, overdrive transmission, & lock up torque converter... the 4.3 might save 3 mpg over the 5.7. Honest, you have some additional pumping loses due to more displacement but for the most part it still takes X amount of power to push that same car down the road at the same speed and if you are useing the same fuel to provide it, both engines are going to require about the same amount of fuel to provide the power required to get the job done. Its a mathematical fact.

My 509ci or 8.3 liter powered Cutty got 17.0 mpg hwy about one less than my 307 in the same car with the same transmission & gear. About 4 mpg less than a fuel injected 3.8 in another gbody that I drove ie same driving habits location roads etc. I think you will be disappointed in the swap and putting your focus on finding out what your actual measured mpg is and what you can do to improve it would be time and money much better spent.

Do you have an overdrive transmission? Lock up torque converter? Efficient vacuum operated spread bore carb or a fuel slobbering square bore? Start with the actual measured mpg over a few like tanks full so that you are not throwing darts in dark. Mileage gained starts with mileage measured just like power gained starts with power measured.

 

[oldmansmonte]

Both engines optimized with the right carb, timing, intake, cam, gear, overdrive transmission, & lock up torque converter... the 4.3 might save 3 mpg over the 5.7. Honest, you have some additional pumping loses due to more displacement but for the most part it still takes X amount of power to push that same car down the road at the same speed and if you are useing the same fuel to provide it, both engines are going to require about the same amount of fuel to provide the power required to get the job done. Its a mathematical fact.

My 509ci or 8.3 liter powered Cutty got 17.0 mpg hwy about one less than my 307 in the same car with the same transmission & gear. About 4 mpg less than a fuel injected 3.8 in another gbody that I drove ie same driving habits location roads etc. I think you will be disappointed in the swap and putting your focus on finding out what your actual measured mpg is and what you can do to improve it would be time and money much better spent.

Do you have an overdrive transmission? Lock up torque converter? Efficient vacuum operated spread bore carb or a fuel slobbering square bore? Start with the actual measured mpg over a few like tanks full so that you are not throwing darts in dark. Mileage gained starts with mileage measured just like power gained starts with power measured.

Everything you said is right about fuel efficiency, but if this guy is having money concerns that 4-7 mpg is the difference between being able to drive the car and having the car sit, he should sell it. For one his dad did the original swap back in 93, he should probably ask him what he thinks. He might feel putting the 4.3 is bastardizing the the hard work he put into it. He might also be upset with the car being sold. All I know is puting a 4.3 in that car will strip it of any value.

 

[azmalibuwagon]

If you know someone with a 2wd S10 that has a 4.3 in it, that's who you should be talking to.

FWIW, I have one of those 2wd S10's, and personally I wouldn't put the 4.3 in my wagon. It's reliable, and power is ok, not great, but the gas mileage isn't very good - only about 20 mpg in the truck. So I just don't see any advantage to it.

 

[DRIVEN]

^^^Valuable advice from someone who knows.^^^

 

[jrm81bu]

I've owned quite a few S10's and Blazers. I like them and the 4.3. Even though the current one keeps giving me fits. Just for the record the current one is a 92 Blazer with the early Vortec 4.3. Valve seals are leaky hene smoke on start up. However I have 11,000+m miles since it's last oil change and i've added less than a quart. I'd call that average, not horrible. If I were to swap one, from a relibility stand point(and cost), i'd stay with a tbi 4.3.

All that said, I really dont' know that it would be worth it in the long run.

 

[Kwik_Cutty88]

If I were to swap a newer model V6 engine, I would stay away from the VORTEC. The fuel "spiders" under the intakes are a pretty common failure part, and it runs about $400+ for the replacement. I would go with either a 3.8L Camaro RS engine or a newer Camaro/G8 3.6L (they are like 255hp and get 28mpg)

you'd be insane to want any gm v6 after the 3800 series was discontinued, they are all trash (except for the pickup truck engines)

The 3.6L thats in my moms 2011 Malibu LTZ screams, and at nearly 40K miles we havent had any problems yet....and Chrysler Corporation bought that engine for use in their jeeps, and they upped horsepower to 323 for use in the 2013 V6 Camaro's...so I'd say its pretty solid. 8)

 

[dogsht]

Two different 3.6 motors.

 

[Kwik_Cutty88]

Two different 3.6 motors.

...oops. My bad.

 

[dream on mcss]

If I were to swap a newer model V6 engine, I would stay away from the VORTEC. The fuel "spiders" under the intakes are a pretty common failure part, and it runs about $400+ for the replacement. I would go with either a 3.8L Camaro RS engine or a newer Camaro/G8 3.6L (they are like 255hp and get 28mpg)

you'd be insane to want any gm v6 after the 3800 series was discontinued, they are all trash (except for the pickup truck engines)

The 3.6L thats in my moms 2011 Malibu LTZ screams, and at nearly 40K miles we havent had any problems yet....and Chrysler Corporation bought that engine for use in their jeeps, and they upped horsepower to 323 for use in the 2013 V6 Camaro's...so I'd say its pretty solid. 8)

Yeah i can definitely agree with you there, they are solid motors. The technology they put into these sixes nowadays is amazing, most of em have already broke 300hp and still get 30 plus mpgs. Thats how everything should be, power when you want it, fuel economy when you dont. But still even though they have all this power it sucks that the computers limit everything so you never really get em to their full potential. Still fast as sh*t though, lol.

I should also add, while like i said before the 4.3s are strong motors, if your looking for something with some good power and better economy, one way to go would be to take the 3800 series ii from the 4th gen camaro, thats 210hp right there. Then for about 40 more hp, take the supercharger setup from the grand prix and throw it on there. BUT you need to atleast get the longblock out of the camaro, as the 3800 in the grand prix is a fwd setup and it would take alot more work to get it in there. Then all you need is the supercharged intake, computer, and wiring harness from the gp and you're good.

EDIT: sh*t i forgot that on the grand prix, because its fwd, the throttle body would be at the rear of the engine, unless you could fabricate some piping you would have to cut a hole in the firewall to accomodate for it, either that or make some custom pipes to move the tb up front or on top or something. BUT, if you could get this to work, you'd be able to put the six speed in the 4th gens behind it.

 

[clean8485]

Dream On, GM has been having issues with the newer 3.6 engines with timing chains, so they're not quite as reliable as you might think.
Miller, in the end, its your decision on what you decide to do with your Regal. If you're concerned about fuel economy and decide to do the 4.3 swap, I'd be interested to see how it turns out. Since the car was originally built with a 3.8, and the 355 was swapped in, the car will only be worth whatever a potential buyer is willing to pay for it.
All I can say is good luck with whatever course of action you decide to take.