I just installed a freshly rebuild 350 on my 77 chevy 1-ton 4x4. I have a edelbrock performer intake manifold and a 750 CFM Edelbrock Q-Jet carb (#1902). My gas mileage is right about 9 mpg, how can I improve this number? Should I put the stock 2 barrel carb and manifold on? Also, it doesn't have much power and the carb sounds like it is sucking in air, is this typical for a fresh 350 bored over .030? I'm gonna adjust the valves at 500 miles and time the engine, I haven't got it timed right. Also, it idles great, but when I give it gas, the engine is a little behind. Any ideas are greatly appreciated

first off, at 9mpg you're nopt doing too bad but a few ideas are as follows:
timing is going to affect both off-idle power AND gas mileage, alot of your power may be going out your tailpipe in the form of unburnt gas. Another thing, what distributor are you running? maybe you need to check ans see if the vacum advance is working if you have one? and maybe you need to buy a re-curve kit with lighter springs and new bushings for your mechanical advance.......just my .02


-Scott

Um...if you don't even have 500 miles on it yet, and you don't have the timing set right, why in the hell are you asking about gas mileage? Is your oil pressure good? Is anything leaking? Is it staying cool? These are the things you shoud be concerned with, not gas mileage. Your motor will need almost 1000 miles on the clock before it will really be making the power it should and getting the gas mileage it should get. You need to get your timing nailed down first thing, and keep an eye on everything, setthe valve lash, and run it, it will get better. A buddy of mine finshed his 429 three hours before we left on a 500 mile round trip run, it took four tanks of gas to get there, one more to play around on the dunes for the weekend, and 3/4 of a tank to get back. Most people call it the BREAK IN PERIOD.

"Is your oil pressure good? Is anything leaking? Is it staying cool? "

Oil pressure is reading about 30 idling and 60 when running pretty hard. Engine isn't leaking at all, tranny is (Jackass that owned truck before me filled transmission and transfer case as full as possible, front and rear seals are shot). Stays at 1/4 in temp gage 90% of the time, on a 45 minute drive during the day, it got to 1/2 on gague, is that too high? Thanks for responses

Also, when should I change the oil? I had to at about 200 miles because the oil pan gasket was leaking pretty bad, I put a new one on and it seals great. How long should I go before changing the oil again? Thanks

I got about 9mpg during the break in period on my 350. Now with 9000 miles on it I get 12-15 depending on my driving style. I run 4.10 and 35"MT. Gas mileage is directly related to the effiency of the engine and until the engine "wears in" the friction is pretty high. This is why you should change the oil at 500 miles - its working harder during break in. Do you have a stock camshaft? If so you need to consider a higher performance aftermarket cam to help the engine breath.

what cam do you recommend? It has the stock one in there right now. Thanks

its a 5.7 350, not a 2.8 6cyl, there is your answer

Originally posted by greaser
what cam do you recommend? It has the stock one in there right now. Thanks

The best thing to do is call the cam help line and talk with a rep. I like comp cams but they aren't the only choice...

I really liked the 260 comp cam I had in my old truck. The intake was a performer and performer carb.

I just built a stroker for my truck and used an Engle cam..
The tech guys there are great, and they can tell you if the cam you want will let you pass smog or not if you have to worry about that.
I used a dual grind camshaft and love the results.
I got a 480 E lift and 440 I lift with 220 Duation on the exauhst and 212 on the intake set on a 112 degree center it's got a nice little lope when you idle but you can't feel it, but when you just touch the throttle it smooths right out and hs great low end torque. the Cam was bout 93 bucks plus shipping.I had a new crane in the motor the first time and it went flat after 3 hours of break in. cost me a couple of hundred bucks to go thru the motor again and redo alot of stuff. I really recomend Engle.
Hope this helps a little.

Thanks all for your replies! Where can i get an Engle cam and what is the number for the info line? thanks agian for all the help. I will also check the 260 comp cam.

The number for Engle Cams is
310-450-0806

The cam I got is part# EP16-18H
This is the one That I am running now.

Hope this helps.