Headers vs 340 manifolds

Headers vs 340 manifolds

340 with basic mods

https://www.motortrend.com/articles/mopp-0102-1970-340-high-performance-mill-dyno/
Phase 1:Stock 340 baseline, Chrysler electronic ignitionPhase 2:Replace small production AVS with Edelbrock 800 CFM carbPhase 3:Replace factory HP manifolds with Hooker 151/48-inch headersPhase 4:Replace factory iron 340 HP intake with Edelbrock Performer RPM Air GapPhase 5:Replace SSI springs and retainers with Engle #604LS retainers and #993 springsPhase 6:Replace stock 340 HP cam with Comp Xtreme Energy 268

Dyno Results
Westech Performance Group
Superflow Dyno
Horsepower
RPM	Phase 1	Phase 2	Phase 3	Phase 4	Phase 5	Phase 6
3000	185.2	195.5	199.6	206.4	206.2	214.7
3200	195.4	206.1	213.9	220.7	220.8	229.3
3400	208.9	224.6	233.0	240.6	240.5	251.5
3600	224.8	238.7	252.7	260.8	259.9	275.7
3800	236.4	253.7	266.6	277.0	276.9	298.1
4000	249.5	267.6	280.0	291.8	291.8	311.7
4200	259.3	278.9	292.9	306.0	306.2	327.1
4400	265.0	287.1	304.3	321.3	321.3	344.6
4600	268.8	297.2	313.3	335.2	334.7	355.9
4800	274.7	306.8	321.1	343.1	342.5	366.7
5000	278.5	312.7	329.1	352.6	350.4	377.0
5100	280.2	316.9	330.6	354.5	352.4	381.3
5200	281.3	316.9	330.8	353.6	353.6	384.3
5400	273.7	314.9	329.3	350.8	355.4	386.1
5500	273.5	313.9	330.4	350.7	355.9	387.4
5600	269.3	314.5	330.2	350.9	353.5	389.4
5700		312.7	329.3	348.6	353.3	391.6
5800		308.8	326.2	347.6	351.4	387.2
6000				329.2	353.4	383.7
6200					314.8	373.7

Torque
RPM	Phase 1	Phase 2	Phase 3	Phase 4	Phase 5	Phase 6
3000	324.2	342.3	349.5	361.4	361.0	375.8
3200	320.7	338.3	351.1	362.3	362.3	376.4
3400	322.7	347.0	359.9	371.6	371.5	388.4
3600	328.0	348.2	368.7	380.4	379.1	402.2
3800	326.8	350.7	368.4	382.9	382.7	412.0
4000	327.6	351.3	367.6	383.1	383.1	409.3
4200	324.3	348.8	366.3	382.7	382.9	409.0
4400	316.4	342.7	363.2	383.5	383.6	411.4
4600	306.9	339.3	357.7	382.7	382.1	406.3
4800	300.6	335.7	351.4	375.4	374.8	401.3
5000	292.6	328.5	345.7	370.4	368.1	396.0
5200	284.1	320.1	334.1	357.2	357.1	388.1
5400	266.2	306.3	320.3	341.2	345.6	375.5
5600	252.6	295.0	309.7	329.1	331.7	365.2
5800		279.6	295.4	314.8	318.2	350.6
6000				288.1	309.3	335.8
6200					266.7	316.6