I have to put new exhaust manifolds on my 454 because one is warping. I all ready have 3" exhausts from the OEM manifolds back. My question is are headers worth the effort?

I have used Thorley headers on two coaches. Really like them. The wiring on the right side needs a bit of heat shielding and the header bolts need tightening now and then. They have a lifetime guarantee. www.summitracing.com is best price.
Gale Banks sells a package that is good but pricey. Fun to read their material, though.


Here are some test results from a fellow who did pretty much the same to his coach as I did:

GM P30 Performance Improvement Note: Modifications performed in stages
Vehicle: 1988 32' Bounder on GM P30 Chassis Test Conditions: Hill climb, paved road, 7000' Elevation, 6% grade, .5 miles Test Technique: Start hill @ 50 MPH, full throttle and manually shift for best speed. Metric: Speed at top of hill.
Stage 1: All stock, new plugs, wires, carb adjustment etc. Stage 1 Cost: $0 Stage 1 Result: 43 MPH 2nd gear, speed still falling
Stage2: Added self fabricated air scoop*, 2.5" dual exhaust w/HP mufflers,cross-over pipe.
Stage2 Cost: $350 Stage 2 Result: 48 MPH in 3rd gear, speed still falling.
Stage3: Added Doug Thorley Headers. Stage3 Cost: $600 Stage3 Result: 53 MPH in 3rd gear, speed holding steady Note: Stage3 allowed acceleration up the hill
Stage4: Added Gear Vendors Gear Splitter
Stage4 Cost: $2700
Stage4 Result: 58 MPH in 2nd and Over, Speed holding steady
Note: Gear Splitters effectively double the number of forward gears. The benefits are obvious in many ways but are not fully
appreciated until you have tried it. *I made the air scoop from a 2.5"x14" furnace floor register and 4" round flexible furnace ducting. I removed the silencer/flash suppressor from my air cleaner and connected the 4" duct to the air cleaner snorkle. The scoop hides easily behind the motorhome grill out of sight but in unrestricted air flow.

I should add that on my gas Barth I modified a heating fitting to be 2 inches high and mounted it under the bumper. I am reluctant to put anything in front of the radiator that would compromise cooling.