hard to tell, if I knew that kind of stuff for sure I'd be really happy.Depending on driving habits and how well it's tuned you could probably end up with anything from 12-18 mpg, or maybe more if you're lucky. I've seen people with 400 horse V8's getting 23mpg before. BUT, near impossible to say... Granted probably better than I'll be getting since I'll be running a bigger cam.at least be happy for THAT.

 

oh really? that much ya think, because i thought that even just a stock 350 only gets around 15 mpg...oh what cam are you getting?

 

Jason, from what limited driving I have done with mine the mpg is not that good. I would estimate about 11-12 mpg maybe more if I drive it nice,,,,, but why would I do that?

If I went to a 700R4 I might get another 4-5 mpg.

 

ok, so i dont know how a 383 with more HP,displacement and torque would have better mpg than a stock 350? thats what im going to get, the 700r4

 

Engine size has nothing to do with economy. Well, it does to some extent, but yeah. A motor you build can be more efficient if you pick the right parts. I'l getting a Magnum 270cam from Comp cams. It also depends on atmosphere too, It seems like ppl in this area get better mpg than a lot of other places. The 383 is making more compression, for one, and the 383 is going to make the same power with less effort so it saves the extra gas a 350 may need to equal it. Plus, that 700r4 will bump you up a bit. Edelbrock sells a big block (I believe the 555ci) that was reported to get 19.8 mpg in a '68 Nova that my brother knew of. Parts make a big difference!

 

oh ok bob..oh thats a nice cam, gonna get you some good power wow thats crazy to think of a 555 BB getting almost 20 mpg.. lol yeah i guess parts do

 

Yeah, I got the flow #'s from my heads and put them in cam-quest to see what it would say. It added about 40 horses over what it was with just "high performance mods" heads. Kicked it up to 480 horses although I doubt I'll make ALL of that. I'm still guessing it to be around 450 or so.

Yep, parts do matter. Lobe separation, valve overlap, duration... The LS7 Corvette are reported to get 28 mpg on the highway and they have 500 horses. Of course that's helped along a bit by two overdrives...

 

wow even 450 is still some pretty sweet power you can raise some fronts with that lol...lol yeah that always helps but i'll atleast have one OD later on