Could I get away with this?!?!?!?...

[iluvmy72]

I am aquiring a 1996 2500 4wd Burb with a bad engine(bottom end gone) Could I put 4.3 Vortec from a Astro van in it? I checked and the body weight is almost the same between the two. I'd probably put a more economic rear end in there as well. Any thoughts? If I plan to tow.....it would be something like a tent trailer.

[FlatBrokeRacing]

I would say go for it.

[tommie]

I don't think it would tow very well at all, and I think it would probably not have much power when you were driving it either. I think there is a reason, GM did not put the v6 in the burb...

[Marv D]

Originally Posted by iluvmy72

..... I checked and the body weight is almost the same between the two. .

Wow, are you sure about that???????

[Sinisterspeed]

Last I checked the 4.3 was 195 or 205 hp. Basically the same mounting as a 350. I believe they even use the same bell housing. Torque might be an issue. Check that out first. Most earlier burbs were far below the hp of the 4.3. I know my moms AWD safari got about 20-22 mph and actually would get out of its own way if you wanted it to. I would say go for it.

[ChevLoRay]

I would guess that it could be done, but all kidding aside, I don't think you'd be at all happy with the lack of performance. You are apparently looking for better gas mileage. If you have a big anything and you put a smaller-than-normal engine in it, it may very well move it around but in the end you'd be flogging it to get into traffic and up hills and if you pull any kind of weight around with it, the mileage will only get worse.

Large engines in small vehicles will often get better mileage than a small engine in the same vehicle. If you put a 100 Watt (RMS) amplifier in a stereo system with a pair of speakers rated at 25 Watts (RMS), you can drive the speakers with a lot less volume than if the set was the other way around. I used to use this analogy to explain using a higher-powered amp with smaller wattage speakers by using the big engine/small body concept.

But, you can over-drive the small speakers with the big amp, just like you can install too much performance in a small body with a bigger engine. If you put the small engine in the big body, the lack of performance will be like having too little amp with big speakers and then you risk distortion. The distortion of the small engine/large body will be one you don't like.

I just don't think you'd like the results, even if it got you where you want to go. NHTSA has performance minimums that are reflected in acceleration, among other criteria. The 4.3 just didn't meet that minimum or GM would have put the two on the order sheets to help meet their CAFE numbers. With extra loading of the smaller engine, smog issues would probably also become apparent, if you have to have it smogged to get it licensed.