CHEVROLET
1970-75 Tune-up Specifications
| Year | Engine Car Model | Spark Plug Type
(AC)
- Gap |
PointGap | Dwell Angle | Firing Order | Ignition Timing
(BTDC
or Mark)
1 |
Hot Idle
3 |
|
| Std. Tran | Auto Tran
2 |
|||||||
| 1970 | 6-
250hp 7 |
R46T -.035 | .019 | 31-34 | 153624 | TDC | 750 | - |
| 6-
250hp 8 |
R46T -.035 | .019 | 31-34 | 153624 | 4° | - | 600D/ 400 | |
| 8-350
250hp 7 |
R44 -.035 | .019 | 28-32 | 18436572 | TDC | 750 | - | |
| 8-350
250hp8 |
R44 -.035 | .019 | 28-32 | 18436572 | 4° | - | 600D/ 450 | |
| 8-350
300hp 7 |
R44 -.035 | .019 | 28-32 | 18436572 | TDC | 700 | - | |
| 8-350
300hp 8 |
R44 -.035 | .019 | 28-32 | 18436572 | 4° | - | 600D | |
| 8-400
265hp 7 |
R44 -.035 | .019 | 28-32 | 18436572 | 4° | 700 | - | |
| 8-400
265hp 8 |
R44 -.035 | .019 | 28-32 | 18436572 | 8° | - | 600D/ 450 | |
| 8-454
345hp |
R44T -.035 | .019 | 28-32 | 18436572 | 6° | - | 600D | |
| 8-454
390hp |
R43T -.035 | .019 | 28-32 | 18436572 | 6° | 700 | 600D | |
| 1971 | 6-250 | R46TS -.035 | .019 | 31-34 | 153624 | 4° | 550 | 550D |
| 8-350
245hp 7 |
R44TS -.035 | .019 | 31-34 | 18436572 | 2° | 550 | - | |
| 8-350
245hp 8 |
R44TS -.035 | .019 | 31-34 | 18436572 | 6° | - | 550D | |
| 8-350
270hp |
R44TS -.035 | .019 | 31-34 | 18436572 | 8° | - | 550D | |
| 8-400
255hp 7 |
R44TS -.035 | .019 | 31-34 | 18436572 | 4° | 550 | - | |
| 8-400
255hp 8 |
R44TS -.035 | .019 | 31-34 | 18436572 | 8° | - | 550D | |
| 8-400
300hp |
R44TS -.035 | .019 | 31-34 | 18436572 | 8° | - | 600D | |
| 8-454
365hp |
R43TS -.035 | .019 | 31-34 | 8° | - | 600D | ||
| 1972 | 6-250 | R46T -.035 | 10 |
31-34 | 153624 | 4° | 700 | 600D |
| 8-350 | R44T -.035 | 10 |
29-31 | 18436572 | 6° | - | 600D | |
| 8-400 | R44T -.035 | 10 |
29-31 | 18436572 | 6° | - | 600D | |
| 8-402 | R44T -.035 | 10 |
29-31 | 18436572 | 8° | - | 600D | |
| 8-454 | R44T -.035 | 10 |
29-31 | 18436572 | 8° | - | 600D | |
| 1973 | 6-250 | R46T -.035 | 10 |
31-34 | 153624 | 6° | 700 | 600D |
| 8-350
145hp |
R44T -.035 | 10 |
29-31 | 18436572 | 8° | - | 600D | |
| 8-350
175hp |
R44T -.035 | 10 |
29-31 | 18436572 | 12° | - | 600D | |
| 8-400 | R44T -.035 | 10 |
29-31 | 18436572 | 8° | - | 600D | |
| 8-454 | R44T -.035 | 10 |
29-31 | 18436572 | 10° | - | 600D | |
| 1974 | 8-350
145hp |
R44T -.035 | 10 |
29-31 | 18436572 | 8° | - | 600D |
| 8-350
160hp |
R44T -.035 | 10 |
29-31 | 18436572 | 8° | - | 600D | |
| 8-400 | R44T -.035 | 10 |
29-31 | 18436572 | 8° | - | 600D | |
| 8-454 | R44T -.035 | 10 |
29-31 | 18436572 | 10° | - | 600D | |
| 1975 | 8-350
2 bar carb |
R44TX -.060 | - | - | 18436572 | 6° | - | 600D |
| 8-350 | R44TX -.060 | - | - | 18436572 | 8°
13 |
- | 600D | |
| 8-400 | R44TX -.060 | - | - | 18436572 | 8° | - | 600D | |
| 8-454 | R44TX -.060 | - | - | 18436572 | 16° | - | 600D | |
ATC- After top center
TDC- Top dead center
1- BTDC - Before top dead center
2- D- Drive
3 - Where two speeds are listed, lower speed indicates idle solenoid disconnected.
4 - With Air Injection reactor emission system (A.I.R)
5 - With A/C on
6 - With A/C off
7- Std. tranny
8- Auto tranny
9- Marketed as 396 but actually 402 cu.in.
10- New .019, used .016 Turn adjusting screw in Clockwise until engine misfires, then turn screw out 1/2 turn
11- With integral intake manifold and all CA models
12- CA 4° BTDC
13- CA 6° BTDC
14- Manual trans and Air Injection reactor system
15- Also Monte Carlo
16- CA 600 rpm