Inliners International Forums General Discussion Engines Langdons Headers vs Stock Manifold.

On a basix stock 250,With Offenhauser 4 barrel, What type of of torque/power gain can I expect from Langdons headers? Will the difference over stock be very noticeable? I am sure this topic was likely covered here before but the Search function on this site seems to be down.

The search feature seems to be working just fine, be sure you are entering the proper search terms.

Tim

Here is my Gonkulator calculation of it.
These are GROSS (60s style) numbers - open exhaust, etc.
Stock 250, Offy-4v, 390 Holley
Torq 221 at 2700
Powr 161 at 4200

Plus Langdon duals
Torq 230 at 2800
Powr 175 at 4500

If your 250 is old and "loose", ie large clearances, you might get a few more HP than the above but the difference should be comparable.

Will you feel it? Yes. That change is about the same percetage-wise as taking a 283-2v and making it a 283-4v. Most of us have done that swap and felt the diff.

Also, not shown in the numbers above is the fact that you can now go from your 2" (if you're lucky) single exhaust to 2" duals with the Langdons. That will add an additional 10hp or so net and to the wheels. Tube headers are better but at this level probably not by much, and are noisier and leak more.

Just for fun here is some more on the comparison.
Here are the Gtech times from my car, set up as:
63 Nova 2830 lb curb
Powerglide-3.08 10-bolt (no traction problems here...)
Well worn 250cid, low oil pressure, big clearances, but good compression = a few ftlb more than average, while it survives anyway.
All stock and stock single exhaust except:
Offy 4v intake, borrowed from Tom Lowe
Holley 390 on top
With me at the wheel, weather-corrected Gtech says
2.58 60ft (front wheels stayed firm on the ground....)
7.36 330ft
11.24 at 63.17 1/8 mile

DeuceCoupe Gonkulator computes (after some tuning, hey, it isn't THAT good)
2.58
7.34
11.24 at 63.19
17.61 at 76.66 1/4 mile

Now, the rest I have to compare just with the computer since I have not run Langdon's on my actual car.
Lets add the Langdons first thru the little single exhaust
2.54
7.22
11.07 at 64.07
17.35 at 77.78 1/4 mile

Now hook some 2" duals to the Langdons
2.51
7.09
10.85 at 64.5
16.98 at 80.05

Well, that computes to .63 seconds and over 3 mph better.
You will feel that for sure, or anything close to it.

I'd suggest get some Gtech or timeslips on your car before and after the change, then post back so we can compare. I like the real numbers, because I learned long ago that, whenever you spend $$$ on your car, of course it FEELS faster, but you're just feeling a lighter wallet. To get the real diff you have to clock it somehow.