Moparts Tech Archive
Exhaust
SB Dyno Header Test
Magnum vs 340 vs headers dyno testing RESULTSJesse Lackman
Moparts Member
Posts: 430
From: Center, ND 58530
Registered: Jan 2000
Well this has been an ordeal for sure. To refresh Mark Nixon and BluCuda each sent me a set of 340 exhaust manifolds (2863553, 2863549)to dyno test against Magnum manifolds and headers. My test engine ate its cam and I just now got it running again. It's been so long that BluCuda's buddies got to teasing him about his manifolds being on someones race car for the summer! Yikes!
Anyway here are the results;
9-25-02 Tests 599 - 604. The point of these tests was to determine how good the original 340 exhaust manifolds 2863553 left side and 2863549 right side exhaust manifolds perform against the Magnum exhaust manifolds and last, headers. The Magnum vs 340 tests were done using 2”id outlet pipes because that is the size the Magnum outlets were. Two right side Magnums were run in test 599, followed by two 340 2863553 left side manifolds, followed by two 2863549 right side manifolds all in 2” id outlet trim. Next in test 602 a 340 set left and right was run with 2.375 outlet pipes. Next in test 603 dyno headers in 1.625 primary tube diameter, 38 primary tube length and 2.375 diameter collectors. Last in test 604 2.625 collectors were run on the dyno headers.
Test Notes
9-25-02 Tests 599 - 604 36% - RH, 27.86” barometric pressure, 62º F - 74º F inlet air
All Tests
- 6000-3500 rpm
- Amoco Ultimate 34 total
- Holley 4778 700 cfm
- Edelbrock Victor 340
- Hughes HEV4545AS
- Magnum cylinder heads, stock valves no porting
- results corrected to SAE J607
Test 599
- Magnum right side exhaust manifolds 2” id outlet
- Average ctq 361.5
- Average chp 326.3
Test 600
- 340 2863553 left sides 2” id outlets
- Average ctq 360.1
- Average chp 324.0
Test 601
- 340 2863549 right sides 2”id outlets
- Average ctq 373.4
- Average chp 337.0
Test 602
- 340 set left and right 2.375 outlets
- Average ctq 363.0
- Average chp 327.8
Test 603
- dyno headers 1.625 x 38 x 2.375
- Average ctq 396.5
- Average chp 356.8
Test 604
- dyno headers 1.625 x 38 x 2.625
- Average ctq 402.7
- Average chp 362.1
Tests 599-604 various exhaust systems
The engine has zero deck flat top pistons which means it has good working quench with the Magnum heads. The compression ratio is 10.18-1. It runs on 92 octane pump gas on the dyno I can't hear it ping, and there doesn't appear to be any signs of detonation. The Magnum heads are bone stock, valve job only, and have the smaller 1.92 intake valves. The rockers are 1.6 ratio Hughes.
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Jesse Lackman
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