zoomies vs step headers
 

how much if any et loss whould i see if i use 2 1/4 zoomies vs a 2 3/8 stepped to 2 1/2 tube into a 4 1/2 merge collector on my 582 bbc? i've used zoomies on my kb 526 blown alky(1800 - 2000 hp oddy motor)but never on a na motor. love the looks and sound of zoomies but would like imput thanks jeff

are you going to continue to use forced induction on gas? is na non alcoholic or naturally aspirated? not clear on the abrv.

more than likly i'll be using a terminator(alky)

So naturally aspirated. Well with zoomies on a non blown application will make your engine be the poorest performer at the track. The engine will be confused below 4500 rpm or so then clean out and act ok for a few thousand rpm then revert at another rpm higher again. Zoomies provide no help to the incoming air charge to the head and will not give the benefit of sharing exhaust pulses to aid the scavenging effect for the next cycle that a good working collector will. If the length is short it will also burn the hell out of your exhaust valves if you are persistant in trying to tune it that way.
A step pipe or non step, 4 in to one collector type is the only proven set up or a few variations of that for naturally aspirated 4 cycle engines.

thank you great advice i'll stick with my steps. jeff

I know it's apples vs oranges but we had a blown small block in a door car with zoomies, went to a 434" stacks injected engine both on alcohol and tried the zoomies for a couple weekends. I too love the sound of zoomies. O'k changed to 2" 34" primaries with 3 1/2 collector, picked up .15 the first time out and a little more after a little tuning, the car actually needed less fuel and ran faster with the headers.

Zip.

i have to be realistic and use the steps. you really love the stack injection.i knew one guy that ran them couldnt figure them out he went to a hat and ran flawless 8.30's at 161 at 2400 lb 67 camaro.i don't say that to get you pissed it's the only time i ever see stacks.i see you can get systems pretty good pricing what whould you say they have to offer over the hat or the terminator.i do like the look of the un even stack set up. jeff

I've ran my first supercharged car in 1964, i've also been tuning stacks since about the same time. I really don't know how much HP change there is between stacks and a hat or between stacks and a toilet bowl, i think they all can run good. I have a 4.100 toilet on my 377" Malibu, i have a friend that has a 4.100 bowl on his 55 shoebox weighing 2650 lbs with a 396" sm/blk that runs low 5.60's. When i first built my 377" motor we put it in my friends dragster with stacks on it. It ran 5.15 & 8.23 @ 158mph at Memphis. The best i can run in my Malibu weighing 3250lbs is 6.52 and 10.59 @ memphis. So i guess all to a persons liking, but stacks are no harder to run/tune than a toilet bowl or a hat, and also can be dead on. Ref. Jimmy Smith here on RJ, runs a 350" flattop motor with stacks, he runs the 7.00 class with a long petal stop screw, and the 6.50 class wide open in a 3,000lb Camero, and shoots 4.0's lights all nite long.

JMO

Zip.

sounds like i should look into them more.do some research thanks again jeff

I think if your going to have to buy new headers, take a look at these brands.
http://www.racingjunk.com/category/1...ollectors.html

http://www.racingjunk.com/category/1...swept-BBC.html

Both worth ET over any other header, fab shop also makes downswepts.