Besides gas milage and a little hotter temps maybe?

 

You're only increasing displacement by 9%, so fuel economy shouldn't change more than that (unless you're doing more mods at the same time and/or you change your driving habits).

Done properly, there shouldn't be any cooling issues.

The real cons of running a modded motor for a DD are the increased potential for reliability issues, and the added expense if something breaks.

 

cons - you will want to get into it a lot more

 

only thing ive seen is tire life seems to decrease
honestly just the cubic inches should have no real bearing on drivability
you should be able to go a lil bigger on a cam while keeping it equally as streetable as a smaller cam in a stock displacement motor
of course you fuel economy might drop a bit depending on cam of course and most importantly tunning
then you gotta look at drive train parts is your tranny up to snuff
on an auto rear end should be fine i have a buddy runnin mid to low tens on a slightly beefed up ten bolt
but then again ive seen him break one in a v6 auto car soo yeah lol
keep it mild and put the right stuff behind it and it shouldnt give you any trouble in being reliable

 

Right now its not on the table to do, but about to do a cam swap in the fall and if I run across anything thats looks bad while I have the pan off and checking all the bearings its something I've thought about doing, and may consider it in my LT4 truck for some more low end torque in the future if I don't end up replacing the entire truck.
The rear may get replaced soon as its already making alot of noise and banging from time to time, has a bit too much backlash in the gears too after 100k mile and my current tranny setup bangs into 2nd gear extremely hard which ain't good on it, thats going to be changed to shortly after the cam swap...going to a smaller cam.
Thanks for the input

 

Over the years, I have seen some 383 setups that got better mileage than when my car was stock. It just depends on what you do.

 

I had a 383 with a WILD cam (240s duration, comparitively tight LSA, lots of overlap)
it gave me 10-12 mpg with my 3.73s and 3500 rpm stall.
take about 20 degrees out of the duration on the cam and cut cam overlap from nearly 30 degrees at .050" to closer to zero and it would've been a bit better on gas.
stick with 2.73s or 3.23s and it would get a little better. replace the automatic with a 6 speed, hell even keep the 3.73s and gas mileage wouldve gotten better.

its all in how you build the engine. you could build a 383 that has driveability that is better than stock.

 

Doing a 383 Procharger setup with a 3.23-3.42 Gear ratio, 224/230 112 LSA cam, with a 4L80E. Normal Driving on the highway should still net 20+ MPG making close to 700RWHP.
Camshaft OVERLAP and Gear ratio along with the tranny used depends on how driverable the car will be IMO.

 

RPM is not a major cause for fuel consumption, but rather how efficient an engine runs. Throwing 2.73 gears at a certain combination isn't going to change mileage. It may actually hurt it depending on the load, RPM and torque curve of a given engine.
It's just like this propaganda crap we see every day about how speeding consumes gas. That's a bunch of tree hugging drivel. Speed does not consume gas. Having overweight and underpowered vehicles where their owners bury the foot into the throttle, demanding power out of an engine that cannot deliver at every stop light is what kills gas mileage.
It's all about efficiency...

 

Built right and built to be daily driven, no issues. People used to daily drive 383/396 LT1 cars all the time back in the day.