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500ci header size

Bluefish

FBBO Gold Member
FBBO Gold Member
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My 511 is making 700ish hp and uses a 2" maddog header. When is it time to move up in header size and where do you get good in frame headers for a BB and A body?
 
I have a set of marco custom headers salvaged from a friends duster with a 440, but in my opinion they were too big for that engine. They are 2 1/4 x 4", but at least two tubes on each side went through the fenderwell.
I dont know of any off the shelf bigger than 2" in a chassis header. Maybe tti does, but i dont know.
Frankly, i think the 2" is okay for what you have.
 
I have 2" TTI's on my Satellite 512. Work fine. 6200-6500 RPM. TTI may make a step design for the A body?
 
ok, thanks guys. Doesn't look like much out there for my application. I hear the TTI's are a bitch installing.
 
I do see TTI has a listing for an A body RB 2 x 2 1/8" step header. Does look like there can be fitment difficulties to overcome. Their details & footnotes indicate they have knowledge of what's involved.
 
I do see TTI has a listing for an A body RB 2 x 2 1/8" step header. Does look like there can be fitment difficulties to overcome. Their details & footnotes indicate they have knowledge of what's involved.
Just looking at those. Looks like a tight fit for sure. The maddogs i currently have install very easily. They have several slip tubes making installation a snap.
 
I'm running a 2" set of Doug's Headers on a blown 440 making over 900hp, it don't seam to be flow restricted. 2 1/8 or 2 1/4 of course would be better but didn't want fitment issues. These Doug's Headers fit perfect with zero issues.
 
Some say 2" no restriction and some find some power going bigger. Just read a post were a 13:1 511 with a large street cam made 30 more hp going from 2" to 2 1/8" header.
 
We've been 10.01 @ 133mph @ 3,700 lbs. with the 1 3/4" Hedman 78030's.
 
It seems like the header size that works best is a function of cam design and peak engine RPM. Bigger may or may not be any better. With my '65 Coronet I switched from my Hooker adjustable 2" Comp headers to the 2 1/8" Hooker Comp version. No difference. This was with the 452" low deck 7000-7200 RPM big cam motors. So my conclusion is a 2" header can support a fairly large, high flow combination.
 
It seems like the header size that works best is a function of cam design and peak engine RPM. Bigger may or may not be any better. With my '65 Coronet I switched from my Hooker adjustable 2" Comp headers to the 2 1/8" Hooker Comp version. No difference. This was with the 452" low deck 7000-7200 RPM big cam motors. So my conclusion is a 2" header can support a fairly large, high flow combination.
I agree. Bigger cubes move more air requiring larger tube to expel gases.
 
On most all MoPar wedge heads
need something, tube length long tube for torque
shorter tube for RPM
& tube exit off the head as big as the exhaust valve diameter
1-7/8" is usually enough
now if you have a huge cid engine (like 572+)
&/or a boosted &/or N2O combo
a 2" is probably a better choice

Hemi Head design are much bigger
the same thing goes for style/length/diameter of tube

on pretty much any MoPar wedge head (unless it's 400+cfm)
anything really bigger than a 2" tube inside diameter
is not going to net much if any extra HP, may even lose torque
over the 1-7/8" tubes
according to my old head porter Mark Lowe & his flow bench

need to read up on flow & how it works
bigger isn't always better


How to Port & Flow test cylinder heads.jpg


How to Air Flow & How to get it, for cylinder heads #1.jpg


How to Air Flow & How to get it, for cylinder heads #2 revised.jpg


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even the shape angles & size of the tube exiting 'the exhaust port'
straighter is better, an upwards swept tube is in many cases better
especially for flow
but almost impossible to do in a car with stock shock towers

Even the old heavy *** cast iron S/S & Ramcharger
413/426 wedge style exhaust manifolds
were really good exhaust scavenging manifolds,
headers build similar would work extremely well,
albeit they are extremely heavy, copy them with tubing
& it'd be great

Exhaust 413ci-426ci 62-63 Max Wedge Cast Iron Mopar Manifolds.jpg


Exhaust 1964 Dodge Max Wedge Ramcharger Pass side.jpg


or fender well style headers, like the ol' 383-440 style

Exhaust Fender Well Headers Moapr BB Dougs Headers.jpg


scavenging style 4-2-1 collectors help too
albeit a tad heavier that atypical 4-1 collector
even the 3" scav. 4-2-1 flow better
than the 3-1/2" 4-1 style

Exhaust Flowmasters Scavenger Series Collectors C134218234.jpg


added edited;
you also should if you run uncorked
probably figure out what length of extension on the ends
of the header collectors
unless you are extremely lucky & get a perfect set of tuned
headers/collectors for your specific combo
(that's highly doubtful)

we use to put some like 20"-24" extensions
(then cut them to needed length)
whatever diameter the I/D of the collectors are
on them to figure it out
*do a couple of burnouts into 3rd &/or some hard launches, 330 ft or so
we used a white oil-based leather type shoe-polish
(usually ended up like 12"-16" in length, ballpark)
put a thick consistent streak/stripe lengthwise down both of the extensions
run it like said above, a couple times

*where it blacken's/burns off, the shoe-polish stops or fades away most,
that's about the point you need to cut the extensions too
that's where the heat pretty-much dissipates
any longer than that doesn't do much good

if you are going with a full exhaust
that's where the H-pipe or cross pipe should be too

if that made any sense

----------------------------------------------------------------------------

by the way my 1500+hp Blown Injected alcohol or gas
Max Wedge combo, fully ported in my old altered
only needed 2" - 2-1/8" stepped x with a total of 28" j-bend zoomies
grant you, it's not a collector style header
apples & oranges, but wanted to spec. the tube size

& my ol' 68 Silver RR 383/479cid had 32" x 1-7/8" mid-length
with 3" Flowmaster Delta-flow 50 with Mandrel bent Muscle car system
out the back/tailpipes
it also went 9.77 @ 135 N/A 700+hp full exhaust, 3520#'s
&
8.58 @ 156 on 300 shot N2O, uncorked with a 15" extension
I tried some 2" headers, didn't go any faster

now if you have heads that flow like 400-450cfm+ T/S or pro-stock style heads
that's a completely different level
you will need larger diameter headers, 2-1/8" maybe 2-1/4"
good luck getting them on a MoPar wedge head, totally custom deal
there's a formula for the length tube too
mostly based on RPM & where it makes the best torque/hp
talk to your engine builder/dyno or head porter guy
they will probably know

sorry for the short book
I hope some of that helps

Good Luck

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Last edited:
My 572 only runs 2 1/8". been 150 @3350lbs.
Doug
 
My 511 is making 700ish hp and uses a 2" maddog header. When is it time to move up in header size and where do you get good in frame headers for a BB and A body?
Schumacher Creative Services
www.engine-swaps.com/Page/Products.html

not sure these guys are still up & running after Chinese Wuhan carp
I heard rumors they weren't open still, may be bad info
but I don't see any sign of it on their webpage
seems to be up & working fine

I haven't ordered anything from them in quite a while too

they use to have some great fitting headers
tri-y's & IIRC step headers for A & B bodies & Dakotas

don't remember specifics, may give them a call

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or possibly Dougs Headers too, use to have some nice A-body designs
including the ol' Fenderwell BB B/RB 383-440 headers

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TTI's are an option too
a tad pricey like any good header will be
especially ones that actually fit
 
I also run 2-1/8 x 3-1/2" on my 528 Hemi with 3-1/2" bullet mufflers on my car for the street. I know they are choking it down Abit when on both guns but haven't felt like buying all the tube bends and making larger set of big $$$ headers just yet.
 
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