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Engine Modifications for 390 FE Camper Special

 
tom_m2718
New User
Posts: 15
Joined: 03/08
Posted: 04/03/11 01:48 AM

Hello All:

I have a ’65 F 250 camper special.  I drive the truck daily to work, about 5 miles round trip.  I have recently purchased a 9 foot camper for family camping trips.  With the added weight of the camper and the aerodynamics of an 8 x 8 foot sheet of plywood flat into the wind, and I find my current set up is not quite up to hauling the load.

Here is my current set up:  The engine is a freshly rebuilt 390 FE.  On top is a Holley 600 carb and an Edelbrock dual plane aluminum intake manifold.  Heads, cam shaft, valve train, and block are all stock.  Exhaust manifolds are factory stock, or at least the passenger side one is original from the factory.  The driver side manifold cracked, and was replaced with a ’75 FE block factory manifold.  The two manifolds are slightly different sizes inside, as are the openings for the exhaust system attachment.  This feeds into a 3 inch single exhaust system.  The fuel line is original ford 5/16” hardline to the Edelbrock mechanical fuel pump/filter, and another 5/16” hardline to the carb.  Behind the engine is a T-18A manual, Gear Vendors overdrive, 4.10:1 rear end, and 225/70R19.5 tires.

Here are the symptoms that have surfaced:  The engine does not open up power wise until over 2000 rpm, with a real flat spot between 1400 to 2000 rpm.  Climbing hills on the freeway, even casual ones, has me dropping out of 4th and into 3rd overdrive.  Pushing the throttle open on the long hills has the engine occasionally coughing, as though it was starving for fuel.  I am hoping to improve the performance of the engine and realistically figure out what I should expect.  I do not have plans to drive faster than 65 with the load, and realistically it will probably be 55.

The first modification that was recommended to me was to improve the intake side of the engine.  I am not sure just how to approach this.  I would prefer to keep my power and torque band in the lower RPM ranges, below 4000 RPM.  Most of the modifications I see on the web are aimed at race engines, not really my application.  I would like to keep this within a budget too, enough to stay under the wife’s radar.  Options I have seen range from porting the existing heads to buying after market heads, such as the Edelbrock aluminum set.  A cam change would have to come with this.  On the exhaust side, I am considering a set of tri – Y headers from FPA and a 2-1/4 inch dual exhaust and H pipe.  I understand that increasing horse power from an engine usually requires pushing up the RPM envelope, and I am afraid of pushing things up so much that the low end of the engine drops down to being useless.

Here is another option recommended to me from Dove manufacturing products: a pair of F5WE-A aluminum heads, a comp cams 260H Hi Energy cam and either a stock Tri Power setup for fuel economy and performance or a single 4 barrel Ford Police Interceptor or 428 CJ manifold.  Aside from being pricy, I do not know just what RPM range this would put my engines power band in.  I have to admit, the tri power setup really looks cool, just I am not sure how useful it would actually be in my application.  I would hate to drop 5 grand on parts only to be disappointed in the change in the performance of the engine, something more applicable to a ¼ mile run rather than a long haul up a mountain road.

Thank you for being patient with my long post, I was hoping to be as complete about my situation as possible.  I am hoping to tap into the wealth of knowledge on this site and see what ideas, opinions, and advice you may have for my situation.  I do want to improve the engine and performance.  Ultimately I may have to drop the rear end to 4.56:1, but I want to see what gain this may lead to first.

Sincerely,
Tom  

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waynep7122
User
Posts: 146
Joined: 10/09
Posted: 04/04/11 12:05 PM

a few things....    

do you have electronic ignition..????  if so.. what kind...  factory distributer with a drop in electronic conversion kit?? or a whole 75/76 FE duraspark distributer and some kind of module to drive it...  the blue duraspark modules have been in fashion lately.. some of them have been failing once in a while.. so always.. carry a spare...    you can bake the internal potting material slightly. to remove the circuit board...  use the wiring to hook to a GM 4 pin module and screw that to the inside of the duraspark box/heat sink.  nobody will ever know...   and EVERY store keeps the 4 pin modules in stock..

if aftermarket distributer.. have you read up in the manual that came with it and thought about selecting a different advance curve...   and do you have a vacuum advance???   hooked to manifold vacuum... (vacuum at idle.)


on the carb...    are you using it right out of the box.????   which model is it????   List # ????

between 800 and 2000 RPMs...   most of the fuel metering is done on the IDLE transition ports and idle circuits..

there is some power valve operation in there also but the power valve feeds the main circuits...  if the airflow is not on the mains...    power valve changes won't help..

a few minutes typing the engine operation when the flat spot happens...

is this happening as you are accelerating..????  

or when trying to increase power already at that engine speed...

how about some manifold vacuum readings at

idle....

at 25 mph...

at 35 mph

at 45 mph...


do you have an exhaust shop nearby that can weld in an oxygen sensor bung... so you can install a oxygen sensor and at least a cheep air fuel ratio meter...  so you know where the air fuel ratio is to prevent melting your engine...

you can even and its usually advised to run a heated oxygen sensor.. with a relay to power it up... to provide the best readouts..  

Post Reply
David289
New User
Posts: 16
Joined: 06/11
Posted: 07/13/11 06:44 PM

TOM,I JUST FINISHED MY 460 ENGINE SETUP FOR TOWING WITH MY 1977 CAMPER SPECIAL.
WHILE I KNOW THESE ARE VERY  DIFFERENT ENGINES THE SAME THEORY APPLIES.
NUMBER ONE AS LONG AS YOU ARE NOT GOING THE FUEL INJECTION ROUTE THE AIRGAP INTAKE IS VERY BENEFICIAL EVEN IF ONLY FOR THE IDEA THAT WHEN TOWING IN HOT WEATHER VAPOR LOCK CAN BE A PROBLEM BUT WITH THE AIRGAP INTAKE CERTAINLY LESSENS THE LIKELY HOOD OF THIS HAPPENING SINCE THE AIR CAN GET AROUND THE CARB BASE AND THE HORSEPOWER GAIN WON`T HURT EITHER! 4:56 GEARS...WOW I KNOW GAS MILEAGE WON`T BE GREAT NO MATTER WHAT GEARS YOU USE BUT 4:56 IS WAY TO LOW (UNLESS YOU FREQUENT THE DRAG STRIP)3;50  3:70 OR EVEN 4:11 WOULD BE GOOD CHOICES.SINCE YOU ARE USING AN AUTOMATIC TRANS IF YOU ARE USING THE STOCK TORQUE CONVERTOR WHY NOT JUST GO WITH THE BIGGEST CAM YOU CAN FOR A STOCK CONVERTOR?IF YOU HAVE A HIGH STALL CONVERTOR THEN YOU ARE ALMOST LIMITLESS ON CAM LIFT.THE BIGGEST CAM FOR THE STOCK CONVERTOR WILL GIVE YOU A LITTLE BIT OF ROCK AND ROLL IDLE BUT NOT MUCH.HOW GOOD IS THE CARB YOU ARE USING?COULD THAT BE THE PROBLEM YOU ARE HAVING OR IS YOUR TIMING OFF THAT MUCH.A GOOD SET OF ALUMINUM HEADS WILL WAKE UP THAT FE BLOCK,FOR THAT MATTER EVEN A CHEAPER SET OF ALUMINUM HEADS WILL MAKE YOU SMILE.SO MY THOUGHT WOULD BE....ALUMINUM HEADS AN AIRGAP INTAKE (ELECTRONIC DISTRIBUTOR IF YOU DON`T ALREADY HAVE ONE) YOU KNOW THE CURVE ADVANTAGE OVER A STOCK ONE.A GOOD SET OF HEADERS 3:50 OR   3:70 OR  4:11 GEARS,A 650 0R 670 CFM CARB HOPE THIS HELPS.....DAVE FROM WESTERN NEW YORK  

Post Reply
jjtrujillo90609
New User
Posts: 1
Joined: 05/12
Posted: 05/17/12 12:18 PM

I built my 352 in my 1967 daily driver about 4 years ago. I wanted a hard working "Work Truck". I didn't want to spend alot of money on power parts because I had no intention of building a bracket racer. To keep the cost down, I changed over to factory ford 390 heads. I install oil restrictors in the heads in an effort to keep more oil at the crank and cam. This is actually the weak spot in FE engines that work hard. I installed an isky cam spec'ed for towing and good torque from 1400-5000 rpm. I have a 3:50 rear gear ratio and a 4 spd NP437 from an old UPS Truck. I also installed a Pertronix ignition system, Edelbrock Carb and Manifold. I get approx. 17-18 MPG on the Highway and never have any trouble towing my 4 horse trailer over any grade.  Hope this helps   Cool  

Post Reply
pepsi1
New User
Posts: 36
Joined: 03/12
Posted: 05/22/12 04:03 AM

Your now pushing a Box in the open air,so anything you can do to help in aerodynamics,will be a big help.... Grin  Cool

Lunati cams has a Voo-Doo Cam P/N 6200 good for RV and towing vehicles...The cam I noted at .050/duration of .203/.213 lift @ .503/.524...Carb size a 650 to 700 CFM with vacuum secondaries. Make sure your distributor is working. Set base @12* and total @30* all in at 2000RPM.... Confused
Install new lifters,and valve springs to match the cam,and I would install a Cloyes early timing chain full true roller.

Unless the cam in your truck is made for towing rejetting the carb/ and setting the timing will not help much...You really need a cam that will work for you now in that power range....(Your cam should pull for you in that RPM range)

Bob  

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mustanghcs
New User
Posts: 2
Joined: 10/10
Posted: 08/26/12 09:53 AM

Where is the timing set? At what altitude is the truck being used in?  

Post Reply
tom_m2718
New User
Posts: 15
Joined: 03/08
Posted: 12/26/12 06:50 PM

So far I have not touched the engine's components other than having the distributer rebuilt at "Ignition Engineering".  This seems to have cured many an issue.  I have also installed a pertronix II module and installed a relay system to bypass any resistor wires in the ignition circuit feeding the module.

Thanks for the feedback so far, when I get more time I will dig deeper into the questions some of you raised.

Sincerely,
Tom  

Post Reply
pepsi1
New User
Posts: 36
Joined: 03/12
Posted: 12/29/12 03:30 AM

Tom
  Glad to hear your making progress. Some things take a little time.
Almost any electronic update to your ignition will take the ballast resistor out. You don't need it. The ballast resistor is for point ignitions mainly. It takes battery voltage and cuts it down so it doesn't wear out your points too fast.

"HAPPY NEW YEAR"

Bob  

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