Ok. Here's the scoop. I have a 66 Malibu in need of an engine. I has a dead 350. I'm not sure of the rear end gear ratio but I cruised at 2200rpm at about 65 and it has a t-10 transmission. I was getting really great gas mileage (like close to 20) and want more torque but don't want to screw my mileage. I've scoured all my CHP, Hot Rod and every other mag I have and it seems to me a 383 will have a flatter, fatter torque curve. I only plan to spin the motor to 3500rpm max. My questions are 1) Is the torque curve indeed fatter than a 350, all else being equal? Will that kill my gas mileage compared to a 350? It seems that logically there shouldn't be that much difference, but everything I read says there is. My problem with the last motor was it wouldn't launch the car from a stop, it did pull like a freight train when I hit 3 grand though. Any comments would be appreciated.

are you planning on rebuilding your old engine or buying maybe a crate engine? those strokers make a lot of power but you could get a strong 350 and with a cam decide where you want the torque. i just ordered a cam for my big block with a flat power curve. might be what your looking for. the research your doing is the way to go. graemlins/thumbsup.gif

I'm not sure which I want to do. I'd like to make more power in the 2000-3500rpm range and wonder if it would be better to use a longer stroke. I know I could make a potent 350 cheaper since I have one already, but would a 383 be more appropriate? I only want to do this once. The main question I suppose is gas mileage. I know compression improves power and gas mileage. What about stroke? It should make more effecient power at lower rpms, but is this the reality? How would you get power at these rpms? Would it be solely the cam? What lift? Or is duration more important? Ramp rate? How would this affect fuel mileage? Or is rod/stroke ratio more important? All else being equal, what effect does a longer stroke have? Longer rods? I suppose I may just have to guess and see what happens. I can live with two cams and some experimentation, but don't want to blow a bunch of money on the short block only to redo it.

John, what kind of big block do you have? Can a person get decent mileage with a big block? I love the way they sound and look but I'll be driving like 100+ miles a day.

If you are doing that much driving i would deffinitely go with a small block. Look up cjlandry he is a member on this board. He has been doing some really interesting things with carburators and gas mileage. Really to get the most out of it you might want to go fuel injection, if mileage is that big of a concern.

Daniel

I just built a 383 for my Nova, I know its a little lighter car, but it performs quite well(12.5s) and still returns 18mpg with an M-20 and 3.31 rear gears. I cruise about 2700rpm at 65mph. I am very impressed with it and it didn't cost too much to do. The most expensive part was the Sportsman II heads. I love the 383, my dad also has one, but in a work truck(77 crew cab it weighs about 5800lb and has 4.11s) that gets about 12mpg with plain ol' smog heads. We both used Crane cams and very standard off the shelf stuff. I'd say go for it, but its hard to know what may change in a different car. Good luck with it.

Okay no offense, but why even build a V8 if you only want to rev it to 3500?? and get good gas mileage, to me this seems like the exact opposite about what these cars are about. Are you saying you are never ever going to get on it and rev it past 3500 rpm? or did you mean your cruising rpm is 3500? fuel injection in most cases will give you better gas mileage if you want to trade off some peak horsepower.

I think he is wanting to build an everyday
driver motor that is reliable and not a gas
guzzler. I don't think you would see much
difference in gas milage between a 350/383 if
you are just driving it normal, but the 383
would use more gas if you are driving it harder.
Just my 2 cents. I am building a 383 for my
every day driver pickup.

Keep your cam that you pick small, like 210 or so and smaller at .050" duration so that you keep your gas mileage. Imho...

I bet 3.08's and a "Performer" cam at 204/214 would be great in a 350 SB... But may be very or too small in a 454 BB pdq67

Originally posted by cody:
.....fuel injection in most cases will give you better gas mileage if you want to trade off some peak horsepower. HUH?

Fuel injection will give better fuel economy AND power. That's comparing a properly tuned carb and a properly tuned injection unit. I certainly wouldn't install injection for better mileage though, the initial cost is much higher than that for a carb.

Mike

Thanks for the info guys. Pdq, I'll definitely keep that in mind. I plan to drive this car everywhere. It's just such a cool car to be in. I'm not trying to build a road racer, I just want it to be dependable (I spent three months trying to get a caravan not to leave me walking, screw these new pieces of crap) and get decent mileage while still giving me that rush when I want it. I won't spin it past 3500rpm, not out of choice, I just know that's the hardest I've run it.

Rad Racer, I'd really like to know how your engine is built. That's what I want in a car. I only want to go 13s really, but it's great to know people can run that fast and still get very respectable gas mileage.

Stikman, I'll go look up cjlandry now.