engine performance

Reply Subscribe

Thread Tools

Search this Thread

Sep 25, 2002 | 09:37 AM

boss_351

Thread Starter

New User

Joined: Sep 2002

Posts: 14

Likes: 0

From: lethbridge canada

engine performance

Sep 26, 2002 | 06:35 PM

bubba21095

New User

Joined: Sep 2002

Posts: 11

Likes: 0

From: Minot AFB US

engine performance

I recently rebuilt my 69 300, block bored, crank turned, head rebuilt, new cam(fuel saver) new lifters, engine all new internally, new carb, headers feeding cherry bombs. I have roughly 600 miles on the engine, and have noticed the performance is increasing as expected but the truck is running really rich and has a bad hesitation on take off. Have tried tightening the mixture screw but all this seems to do is make it idle ruff. The timing is set according to the timing marks(the notch on the damper and the marks on the timing marks cast on the timing cover) to 6 degrees BTDC idle set at 600.. Am I missing something or should I continue to work with the screws on the carb, by the way its only getting about 11-13 miles per gallon, any help or suggestions would be greatly appreciated....

Sep 27, 2002 | 12:10 AM

krazdndenver

Senior User

Joined: May 2002

Posts: 298

Likes: 0

From: Denver

engine performance

Your rich mix could be to the exhaust system. Not enough pipe, and not tuned to the engine.
Robert

Sep 27, 2002 | 12:55 AM

bubba21095

New User

Joined: Sep 2002

Posts: 11

Likes: 0

From: Minot AFB US

engine performance

I installed Pacesetter headers and ran 2" dual pipes to two cherry bombs and then out the side in front of the back wheel, should I have ran larger pipes? These are the the sizes of the original pipe and the flange pipe that came with the headers... Appreciate your time any suggestions on how I can get this leaner???? Thanks again...Bill

Sep 27, 2002 | 09:44 AM

dla4634

Junior User

Joined: Aug 2002

Posts: 56

Likes: 0

From: Rochester US

engine performance

This probably wont help with your mixture but have you considered a hotter ignition system. They usually make a big performance/milage difference.

Sep 28, 2002 | 09:26 AM

bubba21095

New User

Joined: Sep 2002

Posts: 11

Likes: 0

From: Minot AFB US

engine performance

Got a Crane XR700 system ordered and on the way, dla4634 think this will make any difference????

Sep 28, 2002 | 10:15 AM

mlf72f250

Elder User

Joined: May 2002

Posts: 799

Likes: 0

engine performance

You could always lower the carb float height to lean it out a little. I set mine about 1/8" lower than the stock spec in hopes of improving my mileage. It gave me a slight hesitation off the line and I suspect a little better mileage, but it's hard to separate effects. Around the same time I gave it a tune-up, advanced the timing, pumped up the tires, etc., and I maybe went from 7 to 9 mpg. An additional complicating factor is that I tightened the steering and added a sway bar, so I drive a little faster now. ;-)

--Matt

1972 F250 Custom Sport Camper Special 4x2 360 2v C6 3.73
Soon to have a 104" wheelbase as part of a Broncification project
My FTE Website -- http://www.clubfte.com/users/mlf72f250/index.html
My Galleries -- https://www.ford-trucks.com/user_gallery/displaygallery.php?userid=1108