Chassis Dyno #2 - Five Years Later

62Ranchero200

62Ranchero200

Famous Member
Greetings Ford Six Fans,

Five years ago, I dynoed my aluminum head 250 when it was barely broken in. The best results were:

140 HP
187 ft-lb torque

Since then, I have made the following changes:

* Swapped out the DUI for a DS2 (custom curved by wsa111) with an MSD 6-AL
* Swapped out the C-4 for a T-5z
* Swapped out the chrome top 13" air cleaner for a K&N filter top high flow 14" air cleaner

Over the last week or two, I adjusted the valves, changed the plugs, went from a #6.5 PV to a #5.5, and went from #70 jets to #71.

Today's best results were:

157 HP
221 ft-lb torque

That's an increase of 17 HP and 34 ft-lb of torque. Most of this is undoubtedly due to the C-4 to T-5 swap.

I found a magazine article where a stock 170 (the Ranchero's original engine) was putting down about 50 HP to the rear wheels - so I've tripled the Ranchero's RWHP compared to when it was new. I also found a CI dyno article where a nearly stock 250 was putting down about 75 HP to the rear wheels - so I've doubled the 250's RWHP.









I also did a pull without the air cleaner, it didn't change the HP or torque readings, so it seems that the K&N air cleaner is not any restriction at all (at least, on a dyno pull with the hood up). The dyno's AFR shows that I'm a bit rich at WOT, so I should be able to improve by using slightly smaller jets for the PVCRs.

I plan to swap out the 272/272/108 cam for a 280/280/108 cam and mill the head to gain about a point of compression. Once that combo is sorted out, I have a Holley 4-V carb that I can use to replace the Holley 2-V carb that I have now.

Thanks
Bob the Builder
 
Bob, was it on a dynajet dyno or a mustang dyno?? Bill
 
Bob, you have the torque as expected from a long stroke 250.
With the better head you should be getting much more HP. The restriction must be in the carb.??
I have a 205" which cranks out 139 rwhp through a C-4. Of course my torque is no where yours is.
I have to increase my torque via gearing.
Wish you the best with more cam & compression.
You might consider a camshaft with a 110 L/C. I would call Jerry @ Schneider cams & give him all your specs & he will design a camshaft far superior to Clay Smith's profiles.
You can mention my name. Will not save you money, but will go the extra mile for a profile for you. Bill
 
fast64ranchero":o9nyr2p1 said:
You need to lean it out a lot. Guessing you will pick up another 5-10% by just leaning it out to 13.5 AFR
Click to expand...
Not with ethanol possibly in ???? amount.
Don't go over 13.1 & that is with pure gas.
Bob needs more carburetor to supply his engine.
13.5 leaves a possible detonation condition which will take out a piston real fast.
 
Gene, with some ethanol in the fuel, 12.5-12.9. If pure gas, 12.8-13.1.
 
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