[DeTomaso] Another 408C on the dyno - TFS 2V heads and Wilkinson exhaust

[Daniel C Jones]

Just thought I'd let you know the results of our initial tuning on a street 408
cubic inch Cleveland Ford V8 that Dave McLain built using the TFS PowerPort 2V
Cleveland heads for a Pantera owner in Denmark.  There were a few
other engines in
the queue so it took a while to get around to dyno testing this one but it was
worth the wait.  The basic engine specs are:

 408 cubic inch Cleveland Ford V8
 TFS CNC PowerPort 225cc Cleveland cylinder heads (TFS-5160T004-C01)
 production iron Cleveland block 4.030" bore
 9.5:1 compression
 Probe dished pistons
 Scat 6 inch I-beam rods
 Scat 4 inch stroke forged crank with Cleveland main bearing diameter
 93 octane Mobil pump gas
 Morel hydraulic roller lifters

Dave flow benched the cylinder heads on his SuperFlo which is the most
conservative
of all the benches I've tested on (I've tested the same heads on both
Dave's bench
and another in town which flowed 20 CFM more):

 Lift   Intake Exhaust
        2.08"  1.60"
 0.025   13.2   10.2
 0.050   31.6   26.5
 0.100   65.1   55.6
 0.150   98.0   80.9?
 0.200  138.0  110.9
 0.250  173.6  138.4
 0.300  204.9  160.8
 0.350  235.4  176.8
 0.400  258.8  193.7
 0.450  282.1  207.7
 0.500  295.0  214.9
 0.550  308.0  217.0
 0.600  318.6  218.9
 0.650  328.4  221.6
 0.700  323.1  224.3
 0.750  -----  225.2

Tested on Dave McLain's SuperFlow flow bench at 10" and converted to 28".
Clayed intake radius but no exhaust pipe.  2.08" diameter intake valve,
1.60" exhaust.  Sounded smooth and stable through the tested lift range.
Like the other Cleveland heads we've tested, there was no appreciable swirl
until higher lift (0.500" and above).  Tested on the same bench, CHI 3V
flowed around the same numbers (with the raised 3V intake ports).  Port
dimensions for the TFS CNC 225 cc heads are:

 Intake port:  2.195" high by 1.485" wide, 1.85" throat diameter
 Exhaust port: 1.470" high by 1.540" wide, 1.40" throat diameter

I designed the hydraulic roller camshaft to peak at 6000 RPM, making
best average
power between the 4000 and a shift point of 6500 RPM.  This power
range works very
well with the Pantera close ratio ZF transaxle.  I spec'd a couple of
intake lobes
for this engine, HR291/356 which has 0.356" lobe lift (0.616" valve
lift with 1.73:1
rocker ratio) and HR292/378 which has 0.378" lobe lift (0.654" valve lift).
Dynomation predicted the higher lift lobe was worth a few HP but it wasn't clear
at the time what the maximum lift of the supplied valve springs was so we went
conservative and picked the lower lift lobe.  Turns out the version of
the heads we
purchased comes with springs with a maximum lift of 0.680" so either lobe should
work.  The final cam specs are:

 Bullet custom hydraulic roller FC291/298-HR9+2
 HR291/356 intake lobess
 HR298/340 exhaust lobes
 236/240 degrees @ 0.050"
 291/298 degrees seat duration
 0.616"/0.588" lift with 1.73:1 roller rockers
 109 LSA, installed 2 degrees advanced

Initial testing was performed with a Holley 750, a Weiand X-CELerator 351C-2V
single plane intake manifold (p/n 7516) that Dave had had done some plenum work
on (welded in runner extensions) and a 1 inch HVH merge spacer:

 http://www.bacomatic.org/gallery2/v/hidden/dan/dan-cars/album04/album07/album08/Weiand_plenum_2.jpg

Dave did a series of pulls to determine the best total ignition
advance, starting
at 33 degrees.  It picked up a bunch going to 30 degrees and picked up
more going
to 27 degrees.  24 degrees hurt HP and torque just a tiny bit so it looked like
25 to 26 degrees total was best.  Subsequent testing was at 26 degrees.  Such a
low mean best spark is an indicator the chamber is very efficient.
It also never
lit up the knock sensor under load like many of the other cylinder heads we've
tested.  We certainly could have gone up at least another point in compression.

Several exhaust systems were tested with the following results (rounded to the
nearest HP):

1. Wilkinson stainless steel Pantera shorty 4-into-1 headers and exhaust
(2 1/4" OD) with stock appearing mufflers:

 552 HP @ 6000 RPM
 518 ft-lbs @ 4500 RPM

That's really amazing power to be pushing through shorty Pantera headers and
mufflers with 2 1/4" tail pipes.  Compare to the following test and
the Wilkinson
exhaust is worth 31 HP on this engine (perhaps more when we test the Funnelweb
intake manifold and 950HP carb).  Given the stainless steel construction, low
cost and HP increase, the Wilkinson exhaust are excellent pieces.

2. ANSA Euro GTS headers and exhaust

 521 HP @ 6000 RPM
 500 ft-lbs @ 4800 RPM

These are the better flowing Euro GTS version of the Pantera ANSA mufflers
and matching headers.  Down 31 HP and 18 ft-lbs to the Wilkinson version.

3. Mustang long tube headers without exhaust (no mufflers), specifically Hooker
Competition headers (part number HOK-6920HKR) with 1 3/4" diameter by 27" long
primaries, 3" diameter by 8" long collector with 12 inch long
collector extensions

 564 HP @ 5900 RPM
 546 ft-lbs @ 4600 RPM

4. The above Hooker Mustang long tube headers with 3" inlet/outlet Magnaflow
stainless steel mufflers.

 555 HP @ 5900 RPM
 535 ft-lbs @ 4800 RPM

Only 3 HP peak more than the Wilkinson exhaust but 17 ft-lbs more peak
torque due
to the long primary headers.  Open headers were worth another 11 HP
and 11 ft-lbs
so I'd bet a cross-over would be worth some power when running mufflers.

On all of these pulls, The torque curves were very wide and flat:

 http://www.bacomatic.org/gallery2/v/hidden/dan/dan-cars/album04/album07/album08/Weaind_Xcelerator_TFS_2V_heads_exhaust_testing.png

Dave needs to get another customer's engine on the dyno but we hope to test
a few intake manifolds.  In prior testing on a 393C iron Aussie 2V heads, the
Weiand placed 3rd of the seven intakes tested with the tall Parker Funnelweb
single plane making about 12 HP more at the top end without giving up anything
down low (started pulls at 3000 RPM).   Makes me wish I'd sprung for the
matching TFS single plane.

Based upon results from an earlier 408C we did with similar cam timing, I'll
wager this engine will pull 20 MPG on the highway at 70 MPH in a Pantera, too.

I agree with Dave that these heads are very impressive, especially when you
think about how low the 2V port entrances are.  Given the wide variety of
intakes and exhausts available, they should work very well in a wide range
of applications.

With a taller single plane, the 950HP dyno carb, an exhaust cross-over,
950HP Holley, optimized exhaust, UPM's hydraulic roller lifter oil and maybe
a bit more compression, this thing could be knocking on 600 HP.

Dan Jones

P.S.  Dave's wife stopped in just as he was making a pull and took a quick
video which has been posted at http://youtu.be/5a6IqHUhxwk