The engine from my Mk II (382100328) has now been rebuilt with dyno tests to
tune the engine and to compare CAT headers with stock cast iron exhaust
manifolds. The tests were conducted today by Precision Machine Service
(Sevierville, TN 865-429-4172) with the following results:
Block 0.020 over
bore (giving 292 cid)
Stock flat top pistons, 9.3:1 cr
Stock heads using 1967
hardware, no modifications
Crane Fireball Cam (~1970) with anti-pumpup
hydraulic lifters
Dual plane Ford part number (~1969) dual plane aluminum
intake
Holley 600 cfm carb
CAT headers Jet-Hot coated inside and outside,
silver
Pertronix Ford-type billet distributor (did not work properly)
Pertronix Flamethrower coil
Pertronix spark plug wires
New spark plugs
Max
power at 38 degrees advance
The distributor seemed unable to fire the coil
properly, giving eratic ignition.
The coil was removed and the distributor
feed changed to an MSD and coil as
installed on the dyno, then the
distributor worked properly with smooth
ignition. Several tests were
conducted as full throttle torque and hp versus
time runs, 8-10 seconds each.
Exhaust of headers and exhaust of manifolds into
2" dia downpipes
were unrestricted (no mufflers).
Header test 1: 271.0 hp @ 4933 rpm, torque
max 308.6 lb-ft @ 4434 rpm
Header test 2: 277.5 hp @ 4950 rpm, torque max
301.8 lb-ft @ 4243 rpm
Max from all tests: 281.8 hp @ 4950 rpm
With stock
cast iron exhaust manifolds
Max from all tests: 250.3 hp @ 4965 rpm, torque
max 283.6 lb-ft @ 3930 rpm
Conclusion: CAT headers are worth about 32 hp with
25 lb-ft more torque at 500
rpm higher peak. The cam (specs long lost)
provides a broad torque band in the
mid-range, 1950 to 5100 rpm, anticipated
to make a strong running Tiger with
shift points at 5000 rpm.
FYI
Alex
Gabbard
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