1969 Dodge Dart Custom Sedan Slant Six, Father-Son Project

I should include some information on what our homework led to for building this particular motor.

The motor has been a fun build; we took a comprehensive look at the car's gearing (A904 + 7 1/4 rear with 2.76:1) and daily-driver status to build it up as a low/mid-RPM torquer motor that ensures this 2800 pound Dart can get out of its own way.


Here's some of the high points:
Rebuilt Heads:
Stock Valves
Hardened valve seats
Moderate amount of conservative port cleaning/smoothing work
Head shaved 0.020"
Erson dual valve springs
Stock rocker arms

Engine Block, Reconditioned stock 1969 :
Polished & Balanced stock forged '69 crankshaft
Cylinders Bored +0.030"
Block decked 0.050", which with the head shave probably gives ~ 9.4:1 compression ratio
New bearings, oil pump, etc, plus some smoothing on the oil pump inlet/outlet areas

Camshaft:
Erson Cams Custom Grind: Intake per 'RV10M', Exhaust per 'RV15M'
254 / 266 Advertised Duration, 110 deg LSA, +4 deg adv
0.435" / 0.435" Theoretical Lift
210 / 218 Duration at 0.050" Tappet Rise

Intake
AussieSpeed 2bbl Long-Runner intake
Holley Avenger EFI

Exhaust
Dual Dutra Dual cast manifolds into custom exhaust

Ignition
Pertronix Ignitor II module in stock distributor
Coil: Pertronix Flame Thrower II, 0.6 Ohm, 45kV
(deleted ballast resistor accordingly)
Wires: Magnecor KV85 Competition 8.5mm
Plugs: NGK Spark Plugs ZFR5N, gapped at 0.044"
(removed crush washers before installation)

Should give about 190hp peak before 5000 RPM, with a torque peak of about 235 ft-lbf in the mid-range.

The motor started on the very first turn of the key, thanks to the wonders of EFI. We did the 20-minute cam break-in process, holding at at 2000 RPM, but have not driven it yet. It has a fairly quiet muffler set-up, but at higher revs I gotta admit it sounds pretty good for an in-line six.

I suspect it'll never do burn-outs off the line, not with the 'granny gear' 2.76:1 rear axle ratio. But it should be peppy enough at speeds. In fact, part of the cam choice had to do with ensuring it was in a fat torque band doing a 3-to-2 downshift at highway speeds (i.e. passing power).