Mopar LA Cylinder Head Comparison

Cylinder Head Comparison
This chart is a collection of published flow numbers for different types of cylinder heads. They are sorted by max intake flow at 0.500" lift, which is frankly a completely arbitrary way of doing it. Our reasoning is that we are looking for high flow at higher rpm. But that doesn't mean that heads higher on the chart are necessarily "better". As a good example of this, note how the W2 cylinder heads are ranked higher than the Edelbrock heads, because at 0.500" lift the intake side flows better. But if you compare the heads across the board, the Edelbrock heads outflow the W2 heads at almost every other point during the cycle. Chances are, the Edelbrock heads probably provide more useable horsepower even if the peak numbers are slightly off. So, it's important to study the complete chart, not just the single data point.
Now, everyone always says that cylinder head numbers are not comparable, that the same set of heads can flow differently on different benches. That is like saying that dragstrip timeslips from two different tracks are not comparable. While it is true that you wouldn't want to treat the exact numbers as gospel, having a look at the flow table at least gives a general idea of what certain heads are capable of producing.

No. Head Type Intake Exhaust

0.05 0.10 0.20 0.30 0.40 0.50 0.60 0.05 0.10 0.20 0.30 0.40 0.50 0.60

1 994 W2 Econo Mildly Ported N/A 60 127 184 232 274 302 N/A 50 105 154 185 200 208

2 915J Fully Ported, 2.02" Valves N/A 62 130 186 239 272 277 N/A 52 101 132 166 173 178

3 994 W2 "Econo" N/A 59 122 182 229 263 265 N/A 51 110 154 173 176 174

4 Edelbrock Mildly Ported N/A 72 135 191 233 260 260 N/A 69 113 142 164 176 183

5 587 Fully Ported, 2.02" Valves 32 63 126 181 230 253 241 24 57 95 132 132 160 179

6 W2 Mopar Perf. N/A 69 120 173 215 244 254 N/A 63 113 142 148 151 151

7 Edelbrock N/A 72 126 179 224 239 242 N/A 66 110 139 158 170 176

8 051 Fully Ported, 2.02" Valves 40 77 137 186 225 228 224 27 52 104 140 159 168 175

9 894 Stock 340X 32 58 125 172 208 221 210 22 45 95 122 135 140 142

10 915J Stock N/A 66 123 170 206 220 216 N/A 63 110 135 145 148 148

11 140 Magnum R/T 34 70 137 181 209 211 211 24 62 111 142 163 168 171

12 137 Magnum 31 60 118 165 195 209 205 23 54 99 131 167 138 138

13 596 Stock 27 53 107 159 185 199 193 22 48 89 114 121 123 124

14 051 Stock 30 50 113 165 188 193 189 23 49 97 123 133 137 137

15 576 High Swirl 31 62 112 160 182 192 187 23 55 99 119 126 128 130

16 587 Stock 27 52 107 162 195 191 192 22 46 87 112 121 124 126

1. Tony West's Rollin' Thunder website, www.geocities.com/alwest_83/
2. Moparts, Carl's Tech Archive, "974 Flow Test Results, Part 2", 2-19-2002, www.moparts.com
3. Tony West's Rollin' Thunder website, www.geocities.com/alwest_83/
4. High Performance Mopar magazine, 7-1999.
5. Car Craft magazine, 2-2002.
6. High Performance Mopar magazine, 7-1999.
7. High Performance Mopar magazine, 7-1999.
8. Mopar Muscle magazine, 1-2000 & 2-2000.
9. Mopar Muscle magazine, 1-2000 & 2-2000.
10. High Performance Mopar magazine, 7-1999.
11. Car Craft magazine, 2-2002.
12. Car Craft magazine, 2-2002.
13. Car Craft magazine, 2-2002.
14. Mopar Muscle magazine, 1-2000 & 2-2000.
15. Car Craft magazine, 2-2002.
16. Car Craft magazine, 2-2002.

Factory Casting Cheat Sheet

051 318/360 1977-83 137 Magnum 140 Magnum R/T 308 360 Swirl? 1989-93 587 340/360 1973-74; 1976 596 318/360 1977-83 915 340/360 1970-72 974 360 1975-76 994 MP W2 Econo
As with anything made by the factory, it's important to keep in mind that factory tolerances are not exactly what we'd call "precision machining". Tony West's website has a page that compares several 915J heads and he shows a 50 cfm difference at 0.500" lift between the worst heads and the best. Of course, Mr. West doesn't provide citations for his flow numbers, so it's not easy to verify them. But still, the evidence definitely indicates that factory castings with 2.02" intake valves and a really thorough porting job are able to return flow numbers in the same ballpark as the best performance heads. The question then is primarily one of cost. Who is doing the porting job? The home porter could save a bundle by spending a couple of days cleaning up stock castings. But someone who is not inclined to get dirty might find it more economical to buy the performance heads rather than pay labor charges on a substantial reworking.
Considering the variation in the flow numbers of stock castings, it might be a good idea to have any set of stock castings flow tested after cleaning but before modifying. That way there will be a baseline for those specific heads, eliminating any guesswork about performance gains.
We've also presented a factory casting number cheat sheet. Most casting number sheets list the data chronologically, which is least helpful when you've got a set of heads sitting at a swap meet and you wonder what they fit. Using this sheet, just take the last three digits of the casting number and see where they came from. This sheet only lists heads that were installed on 360 engines, though as the chart shows, the same castings were often used on more than one engine type. Our data after 1983 remains sketchy so we will add to the chart as we learn more.

No.	Head Type	Intake							Exhaust
No.	Head Type	0.05	0.10	0.20	0.30	0.40	0.50	0.60	0.05	0.10	0.20	0.30	0.40	0.50	0.60
1	994 W2 Econo Mildly Ported	N/A	60	127	184	232	274	302	N/A	50	105	154	185	200	208
2	915J Fully Ported, 2.02" Valves	N/A	62	130	186	239	272	277	N/A	52	101	132	166	173	178
3	994 W2 "Econo"	N/A	59	122	182	229	263	265	N/A	51	110	154	173	176	174
4	Edelbrock Mildly Ported	N/A	72	135	191	233	260	260	N/A	69	113	142	164	176	183
5	587 Fully Ported, 2.02" Valves	32	63	126	181	230	253	241	24	57	95	132	132	160	179
6	W2 Mopar Perf.	N/A	69	120	173	215	244	254	N/A	63	113	142	148	151	151
7	Edelbrock	N/A	72	126	179	224	239	242	N/A	66	110	139	158	170	176
8	051 Fully Ported, 2.02" Valves	40	77	137	186	225	228	224	27	52	104	140	159	168	175
9	894 Stock 340X	32	58	125	172	208	221	210	22	45	95	122	135	140	142
10	915J Stock	N/A	66	123	170	206	220	216	N/A	63	110	135	145	148	148
11	140 Magnum R/T	34	70	137	181	209	211	211	24	62	111	142	163	168	171
12	137 Magnum	31	60	118	165	195	209	205	23	54	99	131	167	138	138
13	596 Stock	27	53	107	159	185	199	193	22	48	89	114	121	123	124
14	051 Stock	30	50	113	165	188	193	189	23	49	97	123	133	137	137
15	576 High Swirl	31	62	112	160	182	192	187	23	55	99	119	126	128	130
16	587 Stock	27	52	107	162	195	191	192	22	46	87	112	121	124	126