I finally broke down and installed a crossover pipe between the duals directly behind the transfer case. what a difference in the torque curve and sound, the exhaust used to make a annoying rapping sound about 3000 rpm when the engine started making serious power all the way to
6500 redline. she starts to pull very hard at 2500 with the crossover pipe installed and the tone is more pleasant to the ears. Just my 2 cents.................-- Mad Dog
I need to do the same to mine so I'm glad to hear of the improvement.
What year and model is your truck? Where did you run the driver's side pipe?
I put full length Flowtech headers on my 1990 K1500 5.7L and need to run a curved pipe from the header flange to the catalytic converter on the driver's side. I have temporarily hooked mine up so I can use my truck. My exhaust tips are running out the sides about 2/3 the way down on opposite sides of the bed (the tips are Chevy bowtie shaped).
I temporarily am running the driver's side pipe below the transmission support but want to run it above the support. No standard pipes will do it..
I wanted to see how others did it before I go and get a custom pipe made. Any suggestions/tips are appreciated!
Tim Bluff City, TN
the truck is a '79 scottsdale short-bed 4x4 hooker competition hedders, 2.5" pipes running close to the inside of each frame rail, flowmaster series #40 mufflers mounted just forward of the rear axle and 2.5" pipes over the axle and out each side behind the tires. the pipes run over the crossmember on both sides and the equalizer pipe is plumbed in just behind the transfer. soon i will add flanges just b4 the mufflers creating a H-pipe assy. that can be easily removed when i need to service the powertrain. this has been a long term project that was purpose built, let me know if you want all the details of the build-up
-- Mad Dog
Very helpful info. Do you have a diagram or better yet, pictures you can post or send to me backchannel? I am particularly interested in the driver's side setup. The detail on the buildup would be great!
Also, the crossover pipe needs to be before the cat and mufflers?
Thanks for the info! Tim Bluff City, TN
i don't run cat's, but the pipe must be installed b4 the mufflers. Dart Iron-Eagle 180 heads with 64cc chambers,
2.02/1.60 valves. Comp Xtreme 4x4 cam 218/226 dur @ .050" .467/.480" lift w/112 degree lobe separation. Proform gear-drive, comp lifters, pushrods, guideplates and pro-magnum full roller rockers. Professional products "crosswind" intake manifold and 600cfm edelbrock carb. Hooker comp hedders, flowmaster series #40 mufflers and 2.5" pipe w/crossover. MSD 6AL, blaster 2 coil and copper-core wires NGK spark plugs (indexed) Halmeter AF-30 air/fuel ratio monitor using heated O2 sensor from Bosch. roughly 425 hp @ 5500 and 450 ft lbs torque @ 4500. The motor comes on the pipe about 2500 rpm and pulls the eyelids back starting at 3000 rpm TH350 tranny/NP205 transfer with twin-stick from ORD, custom driveshafts and now she has 3.07 gears (was 3.73) I still got a lot of work to do.........-- Mad Dog
Re: " i don't run cat's, but the pipe must be installed b4 the mufflers. Dart Iron-Eagle 180 heads with 64cc chambers, 2.02/1.60 valves. Comp Xtreme 4x4 cam 218/226 dur @ .050"
467/.480" lift w/112 degree lobe separation. Proform gear-drive, comp lifters, pushrods, guideplates and pro-magnum full roller rockers. Professional products "crosswind" intake manifold and 600cfm edelbrock carb. Hooker comp hedders, flowmaster series #40 mufflers and 2.5" pipe w/crossover. MSD 6AL, blaster 2 coil and copper-core wires NGK spark plugs (indexed) Halmeter AF-30 air/fuel ratio monitor using heated O2 sensor from Bosch. roughly 425 hp @ 5500 and 450 ft lbs torque @ 4500. The motor comes on the pipe about 2500 rpm and pulls the eyelids back starting at 3000 rpm TH350 tranny/NP205 transfer with twin-stick from ORD, custom driveshafts and now she has 3.07 gears (was 3.73) I still got a lot of work to do.........Yes, a crossover pipe will broaden the torque curve substantially, your power drops off because the stock HEI dies at 4500. The MSD Super HEI kit eliminates the ignition module and plugs directly into the magnetic pickup coil.
Hey, this was a work truck!
-- Mad Dog
Hmmm.. now just gotta figure out how to get the exhaust past the driver's side Tcase drop on my Blazer.....
Go over the crossmember Luke:
Use the pipe bender and go over the crossmember Luke!
Refinish King
Heck, the factory 2 into 1 came over the crossmember on the drivers side. a muffler shop bent the pipe for mine, there is no way i could have done it w/o a pipe bender. They had to put 2 bends in each pipe right after the collectors to route the pipes over the crossmember. The hedders also interfed with the shift linkage, i cured that with torch n hammer technique to the linkage.
-- Mad Dog
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