Hey guys I'm considering making my first engine build up a 383, but there is one thing stopping me. This car is gonna be my daily driver (70 chevelle) and gas money is and option I need to think about (I'm starting college $$$) I was wondering is anybody has had any experience with a 383 as a daily driver, That gets gets good gas mileage (around 15-17) and yet makes a good amount of power (aound 380 and up in horsies, 400 and up in torque) Thanks for your help

The more horses you have the more food they need. :D

I would think that as long as you choose a relatively mild cam, to go along with a compression ratio of 8.5 or 9 to 1, you could build a very managable street 383. A decent dual plane intake and a Q-jet would help reliability. For what you want, I would go with a cam with a lift of no more .435 and duration @.050 of no more than 212 degrees. The reason for the low duration is so that you can still run a stock converter. You might check out the figures on the GM Performance Parts HT 383 and see what they used to build that engine combo with. That's supposed to be a very stout, yet very reliable engine.

I'm currently working on a 383 for my daily driver.

I don't foresee any trouble getting over 400 ft. lbs. of torque and still being streetable.

My idea is that I'm doing so well with a solid cammed 357, 700R4, and 3.55 gears, a 383 and 3.08 gears will do just as well for streetability and low-end torque, and the highway performance will be even better.

I'm getting 23mpg with my current combo.

If I get better than 17 with the 383 I'll be more than happy.

My '67 Camaro with a 9.5 to 1, 406 and a 280/230, .480" cam, M-20, 3.31's and 26.5" tall tires always got about 15 or so on the road!!

I was running her 80 miles a day commuting when I stopped driving her for my first '87, 3-banger Corn-popper..

BUT it sucked when I got the itch to floor her!!

I would putz around about 55/60 or so on I-70 and get bored, drop her down into second and cob her sorta thing... Loved the way the frontend would come up at each gear change and she would take off!! Run her up about 95 in third, pass a couple a cars and back her off in forth and putz somemore... By that time I was almost home..

I bet if you drop a CC 268HE cam in her and just a good stock, Q-Jet, and you will get your gas mileage goal AND run just fine for a mild motor!!

Imho. pdq67

Here's a link to the GMPP HT 383 with all the specs. It shouldn't be too hard to build something similar. This is a relatively tame engine, but it still has plenty of power for what you want.

http://www.sdpc2000.com/cart.asp?action=prod_detail&catid=120&pid=465

Originally posted by cjlandry:
I'm currently working on a 383 for my daily driver.

I'm getting 23mpg with my current combo.
WOW! Thats excellent for a chevy. I would be more then happy with over 15. Currently My 396 Chevelle is getting about 10 miles to the gallon and my 350 Monte Carlo about 14-16 depending on how I drive it. My setup has alot to do with it though,

All else aside with what everyone else is saying about the motor, its important that if you do alot of highway driving (and of course I realize your building a 383 for a reason) (More Power) you should match up your transmission, Tires, and Gears to fit the type of driving your doing. The best way to save gas is to ride low RPM's and a good way to do that is with a 700R4 Overdrive Transmission. Match that up with a set of 3.55 or lower gears. Also, running a larger tire helps too. With that transmission you will still have a lot of power it will just be more practical. On the other hand, In City Traffic (top and go), noting really helps. It’s all up to how you built your engine. I find a TH-400 with 3.73’s or 4.11's to be more enjoyable even though it’s a little less practical.

I noticed something when I put the 200-4r trans in my 355 powered driver. It is a very mild engine with 3.36 gears and a stock converter. With the lower first gear, it now takes more throttle input to leave a light at the same rate rate of acceleration it had with the 350 trans. Before I could leave with very little throttle input, I now have to give it more gas to get the same go. My engine is quite torquey and seemed to like the taller 1st gear of the 350. Of course, with heavy throttle it leaves quicker but I don't drive it that way. I don't know how this effects mileage. Just an observation.

lets see, 380 hp, 15 to 17 mpg. year 1970. the correct answer is no. you can't get high h.p. and great milage unless you cave and drive some new junk, it won't last as long, has no personality, and has $4000 in electronics in the engine alone, my 70 elcamino gets 10, sounds sweet, but with more money she'll get 8 and that will be realy neat.....

He, He!!

"with more money, she will get 8 and that will be realy neat."

Kinda like me putting my foot through the floorboard ta haze the tires through the gears for the h-ll of it!!

I just love ta roll her away from a stop sign, nail her and let the slappers, slap, then feel the frontend come up and away we go!!! Three shifts later, back off ta cruising speed.. pdq67

15-17 MPG should be easy with an OD Trans. and 383. I'm getting 13-14 with my 461 and 400 Trans., and 3.73 rear. But that is with an economy carb. My 350 Monte Carlo getrs 22 with a 200-4R and 3.42s.

Pat Kelley,

I'm glad you mentioned that deal about needing more throttle to get going at the same rate as before. I noticed this right away when I installed my 200R4 with 3.73 rear. I sort of figured it out but was really surprised when my wife drove the car and noticed it right away. She drove the car for 10 years with 307/th350/3.08:1. Said she wasn't too impressed with it's new roller 406/200R4/3.73:1. smile.gif

I think it's the overall first gear ratio that's the culprit. 2.74 x 3.73 = 10.22. This is similar to running a 2.20 close ratio four speed with a 4.56 rear gear. Lots of grunt but the car doesn't roll very far. Takes RPM to get it up to 10-15mph, if you don't give it much gas pedal it slow getting there.

I wasn't expecting this deal, but otherwise the new combo is great. If I had it to do over, I'd go with higher rear gear, maybe 3.23 or 3.31. This would give me better drivability before dropping into OD. Most all of my driving is in-town city streets, often don't get up to a speed to drop into OD.

Tom

Metalmechanic, [i]au contraire[i/]. How about 16+ on the highway with a old-school HP-built 440 ci rat that has enough oomph to get the Old Red car up to 118 in the 1/4 mile.
Trouble is, around town, man, I think Bob West's big dog 500" gets better gas milage! Tripower is great for steady cruise, but with a "triple pumper", having fun around the 'hood is expensive these days!

383 getting 16+. NO PROBLEMO! Copy Chad's design. You'll be there. You will have to pay attention to the 'systems' design to do this right though.

I have a stock sb400 (from a '73 Caprice, 400 torque @ 2400rpm), Holley 670 carb, 200-4r tranny and 3.42 diff. I get 12-13 miles/gal in the city. I have not calculated the hwy mileage but I do 75mph at 2000rpm.

Theo.

Man, I guess then something must be really bad/wrong with my combo :( I'm gettin roughly 8 miles/gallon with my 388ci, TH350, 4.11s out back and 275/60s. I'd love to get at least 12 miles/gallon, heck 15 miles/gallon would be really great!

My Chevelle became a 383 two weeks ago after 3 years as a 350. I hear what you guys are saying about needing more throttle to get moving however with just a bit more throttle after that the car becomes a mini rocket ship and at full throttle its awesome when compared to a stock 350. I am well satisfied.

383 , TH 2004R , 2800 stall converter , 12 Bolt w/3.73 gears.

He, He!! I just gotta, I just do!!

I bet the old stock, 265hp/400 motor's old tried AND true, -929 hy-cam will get you to 15 mpg EASY!! AND have enough lowend to pull a truck!!

You notice the duration at .050" numbers the torque 383 crate motor's cam has!!!

pdq67

I've always wondered if it would be possible to make a 383 have so much torque that you could run a stock converter, a stock 3 speed auto and maybe something like a 2.73 rear, and get 15 mpg and still run with the same guy with a 400 sbc/TH350 w/3k stall converter and a 3.73 rear?