Big Tubes on Small Block

Indycars

Administrator
Staff member
It's already very tight trying to get the header bolts installed. What happens when you go to
a bigger tube? Do they smash the tube so that it narrower and taller?

I've been wanting these for a couple of years now in the 1-3/4 inch tubes -1024VY.

SchoenfeldHeaders01.JPG
 
maybe this info will help,and yes I've used them in the past

no they don,t squish the tube and make it narrow and taller

they suggest you use the adapter plates designed to make the installation of the larger diameter tubes much easier,
to allow the larger tube with more clearance and use a different bolt spacing and pattern,
look closely at the pictures of both the header and adapter
yes the holes in the adapter look small,
thats because, they correctly assume if you, or anyone else,
are using these they must be building a custom exhaust .
and either have prior experience or be willing to ask for instructions,

you WILL need to take the time and effort to custom machine and port match the plates exhaust port,
it needs too be ported larger to match your cylinder heads exhaust port shape, and header primary opening and exact location,
yes this some times results in part of the recessed screw heads being machined away,
and no thats not an issue and yes copper header gaskets are commonly used

you may want to do the calculations on the ideal header design for your engines power range, it may not require a much larger diameter header primary diameter, but it might benefit from longer primary tube length and the merge collector with a longer collector.
doing the math before spending the cash is generally the smart route
http://garage.grumpysperformance.com/index.php?threads/calculating-header-design.185/
829-4411.jpg


http://www.jegs.com/webapp/wcs/stor...&submodel=&engine=&Nrpp=&No=&persistYmm=false


710-67650.jpg

http://www.jegs.com/i/Moroso/710/67...MIqOvSi9Lt1gIVB4JpCh1DlAYNEAQYBSABEgL2rvD_BwE

http://www.jegs.com/i/Hooker/520/11...MIqOvSi9Lt1gIVB4JpCh1DlAYNEAQYASABEgKPDfD_BwE
520-11891_1.jpg

520-11891_2.jpg
 
Last edited:
Do you put thread locker on the adapter bolts when using an aluminum heads or just anti seize?
I guess that means that you use 4 gaskets for both sides?

Those headers do look longer than a standard 4-1 collector, I have to be able to get a muffler inside or outside somehow.
 
I used a generous application of ANTI-SEIZE,

antiseize.jpg


related threads
http://garage.grumpysperformance.com/index.php?threads/header-gaskets.1045/page-2#post-55418

http://garage.grumpysperformance.com/index.php?threads/calculating-required-exhaust-pipe-size.11552/

http://garage.grumpysperformance.co...-between-shorty-and-full-length-headers.1303/

http://garage.grumpysperformance.com/index.php?threads/building-custom-headers.961/

http://garage.grumpysperformance.com/index.php?threads/is-backpressure-hurting-your-combo.495/

http://www.bgsoflex.com/auto.html

http://www.mk5cortinaestate.co.uk/calculator5.php

http://www.can-of-whoopass.com/index.php?pageID=car_stuff&calculator=primaries

http://garage.grumpysperformance.com/index.php?threads/x-or-h-pipe.1503/

http://garage.grumpysperformance.com/index.php?threads/calculating-header-design.185/

http://garage.grumpysperformance.co...ful-exhaust-valve-size-and-header-info.11265/

http://garage.grumpysperformance.com/index.php?threads/how-to-size-a-4-2-1-header-for-my-sbc.2537/

read related threads
http://garage.grumpysperformance.com/index.php?threads/spiral-mufflers-anyone.10365/#post-42725

http://garage.grumpysperformance.com/index.php?threads/c3-side-pipe-exhausts.793/#post-1150

http://garage.grumpysperformance.co...ders-that-work-with-sidepipes.2350/#post-6204

http://garage.grumpysperformance.co...lap-on-factory-headers.3155/page-2#post-66721

on the flush mount socket head screws, in the adapter plates, that screw to the cylinder heads,
if you think about it its rather difficult for the adapter plate bolts to loosen as the header clamps them in place,
and I simply used one copper exhaust header gasket between the adapter plates and header flanges ,

829-4411.jpg

I used a thick , sprayed on coat of copper coat gasket cement,between the adapter plates and cylinder heads and had zero leaks.
copperspray1.jpg


obviously locking the header flange fasteners,with a fool proof locking system, once they are correctly tightened in place to clamp the gaskets firmly, so they can.t come loose is a smart precaution
safe4.JPG
 
Last edited:
you may want to do the calculations on the ideal header design for your engines power range, it may not require a much larger diameter header primary diameter, but it might benefit from longer primary tube length and the merge collector with a longer collector.
doing the math before spending the cash is generally the smart route
http://garage.grumpysperformance.com/index.php?threads/calculating-header-design.185/


USE THE CALCULATORS to match port size to intended rpm levels... but keep in mind valve lift and port flow limitations
http://www.wallaceracing.com/runnertorquecalc.php
http://www.wallaceracing.com/ca-calc.php
http://www.wallaceracing.com/area-under-curve.php
http://www.wallaceracing.com/chokepoint.php
http://www.wallaceracing.com/header_length.php
http://www.circletrack.com/enginetech/1 ... ch_engine/


http://www.pontiacracing.net/js_header_length1.htm

http://www.wallaceracing.com/header_length.php


http://www.wallaceracing.com/Calculators.htm

https://robrobinette.com/et.htm

https://www.gregraven.org/hotwater/calculators/qm-from-wt-hp.php

http://www.bgsoflex.com/auto.html

http://www.mk5cortinaestate.co.uk/calculator5.php

http://www.can-of-whoopass.com/index.php?pageID=car_stuff&calculator=primaries

(YES I RE-DID THE MATH AND REVISED THIS)
From long experience building similar engines, Id bet the result shows a 1.75" primary near 39"-41" with a 3" collector about 19" long will be close to ideal
If your using stepped primary headers, the result will generally have a 1.75" section 15"-17" long and the next larger section 1.875" about 24" with a 3.5" collector about 15" long, but remember cylinder scavenging only works effectively with near zero back pressure, and your cylinder heads port stall and cam duration will both kick in as limitations near 6100-6200 rpm which won,t be an issue as the trans should shift slightly before that rpm.
you should rather easily get impressive performance in that 2000 lb car.
Id think high tens or low 11 second times should be rather easy once the suspension and tires and tuning are tweaked,
yes it should, could,and may be faster,
but that estimates based on average not ideal ,
and really good
results Ive seen,
because t-bucket suspensions are rarely set up ideally


_

crower00471.jpg
 
Last edited:
It doesn't seem the math matches the generally accepted primary tube length. I'm getting a primary length of 45 inches.

BUT, I have not read thru all the information provided. Let me get back to everyone after I've had time to digest the info in the links.

ExhaustPrimaryTubeLength.JPG
 


I just went back through the calcs


Id change the EVOP to 69 rather than 80
if you add 15 degrees to the .050 lift figures youll be very close to the seat timing,
look at the cam card, it shows 54 degrees , add 15 and your at 69 degrees

EVC to 119.5 rather than 114
54 +180+5=239 /2 = 119.5

headercalk.png


800-615-ValveTimingIllustration-002.gif


camshaft_diagram.jpg
 
Last edited:
What good is a calculator if you can't use real numbers?

I think it's asking for the Exhaust Valve Centerline instead of the EV Closing.
 
Sorry Grumpy, I'm just not happy with the online calculators. I think I can make a better one
with parameters that most people will know without a PHD or a lab. I'm trying to blend two
formulas from different authors for the tubing diameter. Anyone can input numbers to come
up with an acceptable output numbers.

I'm trying to find a table that includes exhaust tubing in 16 & 18 gauge sizes from OD of 1.5
inches to 2.25 inches with IDs included. I need this to include in my Excel calculator, anyone
have a link. I've already spent 2 hours looking, it's getting too time consuming. I need to move
forward with my calculator. I have a book called Performance Automotive Engine Math (SA204)
that has a table, but I don't want to input the table manually or accept it without verification.
Much easier to copy a table from a website to include in my calculator.
 
Even if your 100% correct that the on-line calculators only provide a basic place to start on the header design, and are not going to provide exact data, the basic well dyno proven fact is that almost all the commercial headers were and are designed with fit and ease of fabrication as the primary design parameters and max performance far down the list.
low cost and ease of manufacture , and designing a single header too fit as many applications as possible to simplify inventory issues, has almost always been the manufacturers goal.
longer primary tube length has frequently proven too provide both more mid rpm torque and more average torque, and its the torque within 2000-rpm-to -3000 -rpm of the peak torque that moves the car during almost all the time in performance use.
longer tubes cost more money and make the header harder to design too fit well, so most manufactures rather design a shorter header design that may fit several similar cars rather than the ideal longer header for a single application.
icedf3.png

4 into two, into one collector designs (LIKE BELOW)have also proven to be excellent performers,
but the generally work best if the cam timing and high compression are well matched
1110em-02-z+xtreme-team-9-ltr-racing-engines+.JPG.jpg


one of the rather well established racer tricks has always been to run open collectors too reduce back pressure, as
( headers scavenge best, with zero back pressure)
and in many cases, where clearances allowed, we cut the collectors of commercial headers , and welded on pre made extensions
(LIKE THESE BELOW)and almost always saw a boost in performance

https://www.summitracing.com/parts/FLO-C134218234/


FLO421.jpg


one reason side exhaust on corvettes were and are used is the design allowed decent ground clearance AND long efficient header primary tube header designs.
vettessider.jpg


sidepipeexhaust004.jpg

hok-2222-1hkr_xl.jpg


C3 Corvette Header LS.jpg
 
Last edited:
It seems I have already created a calculator for header dimensions. According to the calculator,
I could maximize both the primary length and the collector length to what ever my car can
handle. Even at the higher 5000 rpm, it will use all the room I have and still retain the outside
the chassis design. I was hoping to tuck them in closer, so they are not such a hazard when the
wife gets out of the car, but that's not possible in this situation.

http://garage.grumpysperformance.com/index.php?threads/header-dimension-calculator.11180/

I would like them to be made from 16 gauge tube for durability. Using "Engine #2, I would need a
tube diameter of ID=1.8, using the closest ID of 1.757 would mean that my OD would equal 1.875 or
1-7/8. Therefore I would need the next larger tube than I expected in my first post of 1-3/4" and
stepping up to 2.0".

Do you think I really need that large of primary tube diameter in a stepped header with a merge collector?

HeaderCalculation.JPG
PrimaryPipeSelectionGuide01.jpg
 
You should feel lucky at this point that you don't have to worry about fitting tubes into the cramped space of an engine compartment.
 
yes that easy access to the t-buckets,drive train, and its light weight, on a t-bucket, is a huge plus,
and one of several reasons why they are popular projects , especially with older geezers,who build them as week end toys
who may have the knowledge and experience to realize the advantages.

http://www.classglassperformance.com/23 T.html

obj578geo419pg8p9.png


http://garage.grumpysperformance.co...ow-many-guys-have-or-want-a-t-bucket-rod.934/

http://garage.grumpysperformance.co...-that-makes-many-of-the-cars-desirable.11244/
 
Last edited:
Back
Top