ALL things related to the Ford 351C
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PostPosted: Fri Apr 10, 2015 11:10 am 

Joined: Tue Oct 30, 2012 8:27 am
Posts: 61
Location: St. Louis, Missouri USA
While I'm posting engine results, I thought I'd post the results for another street 408 cubic inch Cleveland Ford V8 that Dave McLain built a while back for a Pantera owner Torben Thøsing in Denmark. Similar dished piston 4" stroke SCAT kit as he usually uses but topped off with the 225 cc CNC ported version of the TFS PowerPort 2V Cleveland cylinder heads. Compression came in at a modest 9.5:1 because we used the larger 72cc chamber TFS 225 heads. As I recall, the parts list included:

TFS CNC PowerPort 225cc Cleveland cylinder heads, p/n TFS-5161T004-C11 (72cc, ti retainers)
production iron Cleveland block 4.030" bore
4.03" bore Probe forged dish top pistons (p/n 14213-030, 1/16", 1/16" with 3/16" oil rings)
Mahle rings (ductile iron top, cast iron second, standard tension oil ring)
SCAT 4340 forged steel rods (6.0" long with 7/16" ARP bolts)
4.00" stroke Scat 4340 forged crankshaft, SVO (Windsor snout design with 351C mains) crankshaft (p/n: 4-351C-4000-6000)
4.03" bore x 4.00" stroke = 408 cubic inches
93 octane Mobil pump gas
PBM/Morel hydraulic roller lifters (street version, standard travel)
Weiand X-Celerator 351V-2V (p/n 7516) single plane intake manifold (modified by Dave McLain)
Holley 750 CFM carb
9.5:1 compression

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

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). For comparisons sake, here are the flow numbers Trick Flow advertises:


The notes supplied by TFS say the was 28" H2O with a 4.125" bore tube and a 1 7/8" exhaust pipe stub. 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

TFS sells the assembled version of the 225 cc CNC ported 2V heads with three different spring packages:

1. Hydraulic Flat Tappet Springs
1.460" O.D. dual spring with damper (TFS-16534)
120 lbs. @ 1.900" installed height
394 lbs. @ 1.175" open
390 lbs. per inch rate
0.650" maximum lift

2. Hydraulic Roller Springs
1.550" O.D. dual spring with damper (TFS-16094)
155 lbs. @ 1.950" installed height
442 lbs. @ 1.250" open
427 lbs. per inch rate
0.680" maximum lift

3. Solid Roller Springs
1.560 O.D. dual spring with damper (TFS-16318)
240 lbs. @ 2.000 installed height
600 lbs. @ 1.280 open
500 lbs. per inch rate
0.700 maximum lift

Note that early heads may have had TFS-32400413 springs for the hydraulic roller option:
1.550" O.D. dual spring with damper
138 lbs. @ 1.950" installed height
430 lbs. @ 1.250" open
420 lbs. per inch rate
0.680" maximum lift

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 Bullet 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 were:

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 done some plenum work on (welded in runner extensions) and a 1 inch HVH merge spacer:


Dave did a series of pulls to determine the best total ignition advance, starting at 33 degrees. It picked up a bunch dropping to 30 degrees and picked up more at 27 degrees. 24 degrees hurt HP and torque a bit so it looks like 25 to 26 degrees total is 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 good 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. 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

Down 31 HP and 18 ft-lbs to the Wilkinson version. The ANSA Euro GTS mufflers are the better flowing version of the Pantera ANSA mufflers and matching headers. The standard Pantera ANSA mufflers and tubular log manifolds are even more restrictive.

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:


We'd hoped to test a few other intake manifolds but Dave needed to get another customer's engine on the dyno so no additional testing was performed. In prior testing on a 450 HP 393C iron Aussie 2V heads, the Weiand placed 3rd of the 7 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). TFS makes a matching single plane that looks like it would work very well. It would be interesting to test one against a Funnelweb. Note the TFS single plane is made in three versions to fit 9.2" deck Cleveland, 9.2" aftermarket (Windsor end seal rails but Cleveland deck height) and 9.5" deck Windsor blocks.

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.

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

Dan Jones
St. Louis, Missouri USA

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