Dave Mclain and Dan Jones have rebuilt 5481 engine and it is awesome.

Spec's that I have: 384 cui Cleveland, A3 heads, 331 intake, 830 annular carb..

Dave writes:

I put a lot of effort into this stuff and I try to do the best job possible. Engine building is so much work anyway why not.... After a break for lunch I spent another couple of hours working on the jetting on your 830 to get it to run as good as possible. I knew that if my Holley was close to 20 horsepower better that there was a lot in the carburetor. The best combo ended up being 92 and 96 jets staggered with 30 degrees timing on the 1 inch HVH merge spacer. This it running through the Pantera headers with a 2 and half inch pipe and muffler I think that should reflect pretty close to what you're going to have in the car. I did some hold and go tests where I held at 5500rpm for 10 seconds before going to 7000 and even then 30 degrees timing was best. I think that after some new bowl gaskets that this thing will be ready to put in the crate.

His Holley that he refers to is a 950.



Images (1)
Original Post
> Dan Jones might be willing to make some comments.
I'll do a full write up a little later this week when I can find the
time but some basics are:
A 4.04" bore Probe forged flat top pistons (1/16", 1/16" with 3mm oil
A 6.125" Scat forged connecting rods
A 3.75" stroke Scat forged crankshaft, internally balanced (Part
Number: 4-351C-3750-6125)
A 4.04" bore x 3.75" stroke = 384.6 cubic inches
A 11:1 compression
A Solid roller cam using Reed ULX lobes:
A 254/258 @ 0.050" (R290ULX/R292ULX), 0.692"/0.701 less lash (0.024"
and 0.026"), 110 LSA
A Competition Cams solid roller lifters
A PBM/Erson 3850 chrome silicon double valve springs with dampers
A Installed at 1.950", 223 lbs seat and 582 lbs open for the intake,
601 lbs for the exhaust
A Titanium retainers
A Rollmaster timing set that's made for the Cleveland block/SVO style
crank combination
A Oiling mods are bushed lifter bores on the right side only with an
0.040" restrictor in the back of the left side galley
A Stock volume and pressure Melling M84A oil pump, Melling oil pump
drive shaft and Aviad Pantera pan
A Clearances are .0025 mains .0022 rods using Federal Mogul mains and
Clevite rod bearings
A Main bearing size is 1/2 under and rods are -1 to get these
clearances with the Scat forged steel crank.
A Romac harmonic damper
A Ford Motorsport A3 high port aluminum Cleveland heads
A Ford Motorsport A331 (modified by Dave)
A 1.73:1 ratio Competition Cams "gold" aluminum roller rockers
A Jomar stud girdle
A Manley guide plates
A SI stainless valves (2.19" intake, 1.71" exhaust)
A Cooling system modifications
A 0.100" diameter block bypass passage plug, petcocks in the back of
the heads to let air out of the rear of the engine with a -4 AN line
from each head that tees together and runs to the suction side of the
water pump with a 0.060" restrictor so that the engine always pulls
coolant and any bubbles out of the back of the heads
A Cometic MLS head gaskets with Fel-Pro gaskets elsewhere
A MSD Pro Billet distributor with bronze gear
A Autolite 3923 spark plugs for street (moderate heat range), AR 3910
for race (about 2 heat ranges colder than the 3923s)
A 30 degrees total timing
A Precision Proformance high port Pantera headers
A 830 annular discharge Holley (from Mark's previous engine)
Mark runs his Pantera in open road races and rarely drives it on the
street.A His ZF has the original gearing so we wanted something that
would pull well from 3500 to 7000+ RPM.A I designed the cam to
maximize the power between 4000 and 7000 RPM, with a torque peak at
around 5000 RPM.A I designed several cams using the Reed ULX lobes and
the one chosen was the smallest (lowest overlap) and had the best power
below 6000 RPM, along with the flattest torque curve.A The Reed ULX
lobes are older designs that are relatively easy on the valve train so
work well in endurance racing and marine applications.A Dave spent
some time modifying the A331 intake.A A 1" thick open spacer was
milled to level the carb and welded to the intake.A On top of that,
several 1" spacers with an HVH 1 inch merge spacer working best.
Dynomation was predicting a little under 600 HP and usually
under-predicts the so I thought we'd hit 600 HP.A Final results were
623.1 HP at 6900 RPM and and 521.6 ft-lbs at 5100 RPM running through
the 4-into-1 Pantera headers with 2 1/2" pipes and mufflers.A The
torque curve is really flat in the operating RPM range.
More details to follow...
Dan Jones

Add Reply

Link copied to your clipboard.