Flathead fire up for dyno ( maybe)

BTW, sounds like that 39 engine is making about what Henry would have claimed, 90+ HP.
Also, look at the torque, pretty well 2X the hp which seems to be about right for the heavy rotating crank/assembly of a Flathead.
 
Henry didn't put a 4" crank in a 39, and power was peak at about 3600 rpm. Hence the questions. Mr fuzzy bits.
Inquiring minds need to know, well I do anyway.
Martin.
 
scooder said:
Bubba, you said it has a 4" crank in it, is the rest bone stock?
I'm not gonna get sucked in to the trap of comparing dyno A against dyno B on power numbers, but hp peaked at 2900rpm? Normally on a single carb flathead the peak is about 3500rpm. Like I said, not talking about the hp number, just the rpm the peak is.
Any idea what's going on here?
Martin.
Click to expand...


Yep we discussed that at breakfast this morning. Seems as if the hp dropped off quite a bit after 2900 rpm. ( 78.95 at 3300) seems as pretty normal for the flathead to drop at speeds above 3500 in the factory ford charts.
At this time we still think we could have a better carb on the engine..
 
From the 1939 Service Bulletin books.......

scan0005_zps2d9a3fd2.jpg
 
BUBBAS IGNITION said:
Yep we discussed that at breakfast this morning. Seems as if the hp dropped off quite a bit after 2900 rpm. ( 78.95 at 3300) seems as pretty normal for the flathead to drop at speeds above 3500 in the factory ford charts.
At this time we still think we could have a better carb on the engine..
Click to expand...

It would be interesting to see what a run with a velocity stack on it would do
(as opposed to a carb spacer).
The power falls off mainly due to intake/exhaust runner restrictions (and/or valve lift) so the old 99 cent trick was to try and ram some air into it.
 
Be good to find out why it's dropping so early. As you said, normal would be dropping at 3500-3600 the Ford dynomometer sheet agrees with this hp peak (not the hp number, the peak rpm) not the 2900 rpm that you dyno is saying.
Martin.
 
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moefuzz said:
Interesting videos you have there..
Is that a Allen Syncrograph Distributor Machine you are spinning the distribs on??


There is one for sale locally here and he's looking for $300. Looks to be an older model and it comes with nothing but the machine and arm. Not sure if they are reliable and or what other do-dads are missing or needed?



Yep the Allen blue syncograph is the caddy of all distributor machines . The ones that are good to have are the ones that use aluminum punch cards in the front of machine.
Anything else is too old to mess with....
Click to expand...
 
Check out the Dyno runs in JWL's book. Very little power above 3 grand in a stock engine, Can we *** u me the engine under test was a 255 or better.
 
That would make it a 260, I'm *** u ming it's a 3 3/6 bore + .040". 8BA rods don't fit through the 3 1/16 bore.
 
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I think the power graph is very close to what I would expect to see on my dyno with a stock 39 cam and a 260 inch engine. Very flat torque curve for excellent cruise characteristics and highest fuel mileage in the "driving range". Quickly dropping as the RPM goes past the cam and porting.
 
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