header size
Mopar Lover
Joined: Apr 2010
Posts: 1,889
Likes: 170
From: Long Island, NY
ds -
Define "very hot", as in HP and max rpm, race only, street only or a little of both.
You won't get any advantage going over 1 3/4" on a small block up to 6 - 6.5K rpm and 1 5/8" is more common for a street rig.
Even a mild/moderate 440 will do just fine with 1 7/8" primaries.
Archer
Define "very hot", as in HP and max rpm, race only, street only or a little of both.
You won't get any advantage going over 1 3/4" on a small block up to 6 - 6.5K rpm and 1 5/8" is more common for a street rig.
Even a mild/moderate 440 will do just fine with 1 7/8" primaries.
Archer
Mopar Lover
Joined: Jul 2011
Posts: 681
Likes: 106
Brememeric is correct on the size of the headers for his old ride and why they worked so well.
When you do the math for flow vs cross section assuming 18ga pipe you get:
A hot 340, assuming peak torque at 4500, specs a 1.76 pipe to have no back pressure in the header. back pressure in the exhaust is different but design should have non in the header. So his sizing was spot on.
A hot or "MAX" 360, assuming peak torque at 5000 ( we'll bump torque peak assuming you are using the 295XE cam you posted about before) and that 360 specs to a 1.90 pipe (thats why they make 1 7/8 pipes). Add a 150 shot of nitrous and you need a 2.07 to be restriction free in the header. Get out the tig welder baby!!
So custom headers or you have restriction in the system.
Any 440 with a 1.75 has restriction at 3375rpm. So if peak torque is designed to be in after that your pipes are working against you.
A text book example of why headers really wake up a some motors with exhaust manifolds.
When you do the math for flow vs cross section assuming 18ga pipe you get:
A hot 340, assuming peak torque at 4500, specs a 1.76 pipe to have no back pressure in the header. back pressure in the exhaust is different but design should have non in the header. So his sizing was spot on.
A hot or "MAX" 360, assuming peak torque at 5000 ( we'll bump torque peak assuming you are using the 295XE cam you posted about before) and that 360 specs to a 1.90 pipe (thats why they make 1 7/8 pipes). Add a 150 shot of nitrous and you need a 2.07 to be restriction free in the header. Get out the tig welder baby!!
So custom headers or you have restriction in the system. Any 440 with a 1.75 has restriction at 3375rpm. So if peak torque is designed to be in after that your pipes are working against you.
A text book example of why headers really wake up a some motors with exhaust manifolds.
Thread Starter
Mopar Fan
Joined: Feb 2012
Posts: 28
Likes: 0
have a cc xe295hl (not used) but i want lunatis woodoo mec,,60442 instead with my ported edel heads (guide cut down a litlle), junior singel plane and holley 850, 4000 stall with big cooler and dual big fan, 3.91 (next 4.33) this summer (engines list before) , the car are more a strip but drives on ouer wekeend racers.
Thread Starter
Mopar Fan
Joined: Feb 2012
Posts: 28
Likes: 0
start my 360 up and test drive..run like he*l.. but one thing is that my elec' pump dont have a chance to deliver all fuel. Go to use one pump near the fuel cell tank and two beside the engine. Have a new mek' carter pump that should deliver up to 500hp, the quest, can this mek pump only and no more do the job??
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