Does blow by cause bad Gas milage?

Im getting 15 mpg on a good day with my POS engine thats eating oil.
Do you think i will get better gas milage with my 302?

flat top pistons with valve reliefs
performer rpm intake
650 holley
e7 heads
e303 cam
new rings


The only difference from the motor now to the new motor is no blow by
and the cam is slightly bigger.
Ive herd of people getting 22 mpg with a stock 4 barrel motor and cam

 

Might just be the plugs getting all crapy.

 

I don't think you will keep your foot out of new engine,,,, so tank to tank,,, no.

Unless you put a egg under throttle,,,, Yes!

 

All the parts need to play and get along with each other to get good mileage. The wrong combination of parts hurts mpg. Just because something works great on my car doesn’t mean you will have the same results on your car. I'm getting 19.75 mpg on long trips with a 400 hp 289 if I act my age. This is with a 3.25 gear and 24.5" tires at 3300 rpm. If I drop the rpm to 2800 gas mileage go down too.

 

I'm getting 15mpg up from 9-10 after I chaged to a T5. I don't have much blowby that I know of. But I had the edelbrock carb tuned for WOT so I know that's hurting my milage quite a bit. I've been meaning to redo it but haven't gotten around to it.

 

I get decent mileage with mine. X303 cam,E7heads,600 Holley, 4:11's. Keep in mind I drive it pretty easy and it doesnt see much throttle most of the time. It only takes a tickle of the throttle around town to get up to speed. Runs around 3300 on the HWY to work and it loves it. Its pretty efficient at that rpm it seems.
Yes blow by hurts mileage. Your down on compression so the engine isnt very efficient. You need to get those cylinders full and burn the fuel.

 

Mabey its that dang holley! im going edelbrock....

 

well statement can start a sure fire argument. i get prolly 15 mpg outta my race car. 750 holley

 

I <3 my holley carbs

http://lmgtfy.com/?q=how+to+tune+a+holley+for+mpg

 

I do to, I just like messing with you guys

 

THIS IS ONE OF THE MOST IMPORTANT NOTES OF ENGINE BUILDING! WELL PUT!!! :Handshake

 

Wont matter. They wont tune themselves.

 

Go ahead if you want to go slower. If you want fuel economy put the 2 barrel back on it.LOL. You guys and your fuel economy....Oh boy. Sorry it just seems odd to me to talk about fuel economy in 35-40 year old carburetor cars.

 

I am getting around 20 MPG with a 302 mild Cam, eldebrock 650 vaccuum secondary and Dual Exhaust and a 4 speed manual. IF i Keep my foot out of it.

If I get into the throttle at all MPG drop DRASTICALLY down to the 13-15 MPG range.

On the other hand I also had another Maverick years ago that had a Holley 650 Manual secondary, jetted out as much as possible. Little hotter Cam single exhaust and a C4 and it got 10-12 MPG on a good day and less when I put my foot to it.

 

If the cam is even relatively close... Im sure you'll pick up MPG because the new motor won't be wore out.

These guys talking of swapping carbs and all of that are making no real points to the thread as you asked would your new motor get better MPG vs old one. You didn't ask what to do to get better MPG.

So, the answer should be yes... you will get better MPG with a motor that's not wore out if you drive the same as you do now.