|
Horsepower
Base horsepower (Bhp) / rpm
Note: 72 figures are SAE net
Bhp
|
300 @ 5400
4V 70
285 @ 5400
4V 71
280 @ 5800
CJ 71
330 @ 5400
Boss 71
266 @ 5400
4V/CJ 72
275 @ 6000
R code 72
|
|
Torque (lb-ft @ rpm)
Note: 72 figures are SAE net
|
380 @ 3400
4V 70
370 @ 3400
4V 71
345 @ 3800
CJ 71
370 @ 4000
Boss 71
301 @ 3600
4V/CJ 72
286 @ 3800
R Code 72
|
|
Compression Ratio (max.)
|
11.0:1
4V 70
10.7:1
4V 71
9.0:1
CJ 71
11.7:1
Boss 71
9.0:1
4V/CJ 72
9.2:1
R code 72
|
|
Bore
|
4.00
|
|
Stroke
|
3.50
|
|
Bore spacing
|
4.38
|
|
Head Volume (c.c)
|
61.3-64.3
4V 70
64.6-67.6
4V & Boss 71
73.9-76.9
CJ 71, 4V/CJ R
code 72
|
|
Crankshaft-Material
- Journal Dia-Main Rod
|
Nodular Iron (Boss selected for
hardness)
2.749
|
|
Con Rods-Material
|
Forged Steel with 180,000 psi nut
& bolt
(Boss & 72 R Code
Magnafluxed & shot peened)
|
|
Length (Ctr-to-Ctr)
|
5.78
|
|
Pistons-Material
|
Cast Aluminum
4V and CJ
Forged Alum.
Boss & 72 R Code
|
|
Compression Height
|
1.65
4V & CJ
1.657
72 R Code
1.631
71 Boss
|
|
Deck Clearance
|
0.035
4V & CJ
0.045
71 Boss
0.019
72 R Code
|
|
Cam-timing-Open/Close
|
Int.
14 /72 Exh.
70 /20 70-71
4V
18 /72
82 /28
71 CJ
14 /76
78 /32
72 4V/CJ
34 /76
86 /24
71 Boss
17 ½ /77 ½
77 ½ /17 ½ 72
R Code
|
|
Duration/Overlap
|
226 /270 /34
70-71 4V
270 /290 /46
71-72 CJ
290 /290 /58
71 Boss
275 /275 /35
72 R Code
|
|
Valve Lift
|
0.427 I & E
70-71 4V
0.480/0.488
71-72 CJ
0.477 I & E 71 Boss
0.491 I & E
72 R Code
|
|
Tappets
|
Hydraulic
4V & CJ
Mechanical
Boss & 72 R Code
|
|
Rocker Arm-Ratio
-
Type
|
1.73:1
Lightweight stamping on pedestal
4V & CJ-non adjustable
Boss-adjustable
|
|
Valves-Head Dia-Intake
|
2.183-2.198
|
|
- Exhaust
|
1.705-1.715
|
|
Valve Stem Dia
|
0.342
|
|
Valve Spring Load
-
CLOSED Int. & Exh.
(lbs @ installed ht.)
-
OPEN Int. & Exh.
|
90 @ 1.82
4V & CJ
92 @ 1.82
Boss & 72 R Code
285 @ 1.32
4V & CJ
315 @ 1.32
Boss & 72 R Code
|
|
Firing Order
|
13726548
|
