5.7L Hemi Swap

[JParker93]

I recently acquired a 1973 Winnebago Brave D20 with the 440/727 combo. I don't have it on the road yet but I am contemplating an engine swap. I have my eye on a 2005 Dodge 2500 truck with a 5.7L Hemi and a 5 speed automatic in it. Has anyone swapped a 5.7 into a camper like this?? Any thoughts on it? I know it is a smaller engine in terms of displacement but from what I have read online the HP and Torque specs aren't too far off and you can beef up the 5.7 to put out as much if not more power than the 440. I'm just thinking it will be a modern engine with fuel injection and will make the old girl more highway friendly and get better fuel economy with the extra gear and overdrive. I appreciate anyone's input. 

[Oz]

The 5.7 is a great engine with lots of upgrade potential. But, for comparison, you can also beef up the 440 and change to fuel injection as well, plus add overdrive and the 5.7 couldn't touch the results.

The 5.7 is far from a plug and play conversion as well. 
If you're looking at such an involved conversion, you ought to consider a diesel, LS swap, weight these options, and choose what you think you prefer best.

[eXodus]

I got a 2004 Dodge Ram 1500 Hemi 5.7, aside of exhaust manifold bolt snapping a great Mercedes product 😛 tons of power and reliable. I'm towing with the pickup heavy for 220.000 miles no issues and but for fuel economy I would get a LS swap. The Hemi loves gasoline, my pickup gets 12-14mpg without nothing attached and 10-12mg with a trailer. My Chevy 5.7L 24Ft Class A gets better fuel economy then the Hemi. For the power - yes a Hemi is a great project, it will pull your RV up the mountains without even blinking. Just don't expect better fuel economy from those years - they only got better after 2007.

But big disclaimer: you can't idle the 5.7L Hemi for extended periods. That's killing the cam. There are some videos about that. "Fatal Flaw" It's a interesting design, as long as you drive and tow heavy no problem. Long stop and go and prolonged idling kills the engine.  It's not a catastrophic failure - but the cam wears down cumulative.
I think in an RV, where you usually - start driving and don't commute, sitting in traffic all day the Hemi could work.

The transmission on the Hemi is nice. 6 gears! Having a modern engine with electronic controls something I like to play with.  Just really don't expect any better fuel economy. - Power yes, fuel economy no.   I mean you still would win - you get more power for the same bad mileage
And no worries about the displacement - 5.7L is still a large engine.  I got a one of those in a 24ft  10.000lbs Class A.   It only starts getting to it's limits when I'm adding my 5000lbs trailer.  I don't think the D20 is that heavy...

[Travcoresto]

5.7 comes no where close to the torque output of a 440 especially in the lower rpm range.  If you are going to swap a hemi, 6.4 is the one to use- but I still would just improve the 440 as a first choice and keep things simple.

[Oz]

I second the above reply.

[Eyez Open]

If I were in your shoes a leakdown/ compression test would be the first move. Switching to a 5.7 would be expensive and labor intensive..Those tests would tell you your engines primary health. If good speaking for myself....Going to a 5.7 would be a costly down grade, restoring the 440 would be rewarding. That is a opinion however.