headers vs manifolds on a 318 2bbl difference ????

-
318willrun said:
Will headers make a difference on a stock 318 2bbl in place of stock exhaust manifolds with dual exhaust??? I say in the video that I used 2 1/4" pipe, but it was 2.5". Here are real world results !!!
Click to expand...

Manifolds do not exactly aid pulse tuning/timing. Because most have a common log there is cross communication that dilutes the incoming fresh charge with hot exhaust on most cylinders.
If the header lengths are about right for the engine there is no or very little cross communication and you get a low wave coming back to the exhaust valve just before the IVO. Carb tuning is probably going to be required. 2V or 4V the intake wave tuning may be different, which needs to match the low exhaust with a high pulse just at IVO.
A 4V with its likely higher flow volumns should see greater benefit.
 
You guys have beat it to death and I will add my 2 cents (without watching the video).
Headers on a 318-2 may not make any more hp without other supporting mods to improve airflow. To add headers and not improve the breathing ability of the intake side is kind of like buying your sister breast implants. They look great but you don't get to use them.
 
496 polara said:
You guys have beat it to death and I will add my 2 cents (without watching the video).
Click to expand...
It made more HP. Added 2 MPH in the 1/8. Also lowered the ET. But you didn't watch the video. Keep your 2 cents and I'll take the 2 MPH
LOL :thumbsup: :poke: :poke:
 
496 polara said:
You guys have beat it to death and I will add my 2 cents (without watching the video).
Headers on a 318-2 may not make any more hp without other supporting mods to improve airflow. To add headers and not improve the breathing ability of the intake side is kind of like buying your sister breast implants. They look great but you don't get to use them.
Click to expand...
Holy F**K, not a F**king clue.....
 
I guess there'd be absolutely no power increase just throwing a 276°/288° cam in a stock 2bbl 'teener w/stock mannys then....:realcrazy:
 
318willrun said:
It made more HP. Added 2 MPH in the 1/8. Also lowered the ET. But you didn't watch the video. Keep your 2 cents and I'll take the 2 MPH
LOL :thumbsup: :poke: :poke:
Click to expand...
LOL!!! That's ~15-20hp depending on what the car weighs, it's a total mystery, how do those 2 tiny barrels flow enough air to fill all those pipes????:rofl:
 
When you've installed dozens of sets of headers, told the customer you're going to have to tune the engine, jets, plugs, timing, and they come back with a big grin, take it to the strip, and improve their time 2 - 4 tenths, then suggest they open the headers for more, - and they get better times, then specifically the 340's, - tell them you want to replace their AFB/AVS with a 3310/780 Holley, and if they don't like it, I'll put their old carb back on, ALL absolutely free for the price of the carb I got for $50 - $80 from a swap meet, kitted and other, - if they kept it.
They come back with a huge **** faced grin.
Have never re-installed the old carb, never, - over a dozen times .
All without a Dyno , just experience.
Good luck .
 
Last edited:
A set of headers on a 69 440 a-body is good for a second. lol
Slicks another second.
 
inertia said:
When you've installed dozens of sets of headers, told the customer you're going to have to tune the engine, jets, plugs, timing, and they come back with a big grin, take it to the strip, and improve their time 2 - 4 tenths, then suggest they open the headers for more, - and they get better times, then specifically the 340's tell them you want to replace their AFB/AVS with a 3310/780 Holley, and if they don't like it, you'll put their old carb back on, ALL absolutely free for the price of the carb I got for $50 - $80 from a swap meet, kitted and other.
They come back with a **** faced grin.
Have never re-installed the old carb, never, - over a dozen times .
All without a Dyno , just experience.
Good luck .
Click to expand...
Lots of people like Thermoquads, but I picked up almost half a second in the quarter, and ET's were a LOT more consistent, when I swapped my 73 Duster 340's Thermoquad for a spread bore Holley 650. Also got better gas mileage, and the Holley didn't vapor lock. Also, the Holley's secondaries would start opening before full throttle, so you could pass someone on a two lane road without downshifting into second. The Thermoquad, either you couldn't make it because the primary barrels were so small, or you'd give it full throttle, kickdown into second, and WAAAAAAAAAA and you'd race around.
 
65 Cuda 340 said:
Lots of people like Thermoquads, but I picked up almost half a second in the quarter, and ET's were a LOT more consistent, when I swapped my 73 Duster 340's Thermoquad for a spread bore Holley 650. Also got better gas mileage, and the Holley didn't vapor lock. Also, the Holley's secondaries would start opening before full throttle, so you could pass someone on a two lane road without downshifting into second. The Thermoquad, either you couldn't make it because the primary barrels were so small, or you'd give it full throttle, kickdown into second, and WAAAAAAAAAA and you'd race around.
Click to expand...

I have had great but limited results with TQs, really like them, but there were the cracking issues, and limited performance parts when I was actively messing/experimenting.
I would cede to anyone with experience with them .
I really enjoyed the Quadrajets I had to use in the past .
 
Last edited:
Killer6 said:
Holy F**K, not a F**king clue.....
Click to expand...
Have at it sport. Guess I will be the dog this time.

looney-tunes-foghorn-leghorn.gif
 
You must log in or register to reply here.
-

Back
Top