headers vs HP manifolds

[anlauto]

I think you really have to consider the purpose of the vehicle. Are you really going to miss 20HP if you're driving to a cruise night or the odd car show ? If you were building a "track only " race car, I could see your concern, but in every day driving, does it really matter ? These people who want to squeeze everything out of there motor for bragging rights make me laugh

[70_440-6Cuda]

I think you really have to consider the purpose of the vehicle. Are you really going to miss 20HP if you're driving to a cruise night or the odd car show ? If you were building a "track only " race car, I could see your concern, but in every day driving, does it really matter ? These people who want to squeeze everything out of there motor for bragging rights make me laugh

On point Alan - I am struggling with that very thing - what do I want the car to be in the end and is it worth the spend to get it there.  Not to mention I love the sound of a loping cam and good headers / exhaust which doesn't align with making everything perfectly original.  That is sort of where I have stalled.  I would agree that you won't notice the difference in acceleration times etc., the difference will be in the seat of the pants impression.

[tparker]

Here is an interesting video showing exhaust options for a mild 440 on a dyno; max wedge, HP headers, and hooker headers
https://www.youtube.com/watch?v=Ez9yfr-0KXA

SPOILER ALERT:
It seems the Max Wedge may be the best option if the hassle of headers are too much. HP was fairly close, though the torque was a bit lower. Cool and interesting comparison.

[70vert]

I agree with the point that a street car/show car does not need and likely wouldn't notice another 20 horsepower, but there is also the sound factor. A huge sound improvement would come from having headers but I'm sure bigger pipes would also help. I do not race my car but when I fire it up and drive it around, the exhaust sound sure brings a smile to my face!!

[crackedback]

What was the premise of the OP's question, HP difference.  It's all what the owner wants on or get out of the car.   Headers aren't for everyone.  No mention of driving or use so lots of assumptions.   He says 5-10 meh, more like 50 he's concerned.

That test posted from Nick is only 45hp...  which is not even close to the same on a 375hp engine.  That test mill is basically a stockish 6 pack deal from the numbers. 5hp, meh,  pick what you want for looks whatever.  40hp... 375 vs 420 isn't even the same zip code. Look at the numbers throughout the range, that is a HUGE performance advantage.  The OP's stroker will suffer the same fate, actually greater delta, is my guess,    Maxi's are a special piece and $$$ that don't fit so they are out anyways, but they WORK. Factory B/E casting, not so much in comparison.

The OP using manifolds based on HP output being close to the same, got sold a bill of goods. That they were close to the same, they are not.  Even the cheap headers are much better than HP's by a good margin.  Magazines are notorious for printing things that aren't quite correct.  There is a long list, my favorite is the 340 with factory unported X heads, xe268 cam, air gap intake making almost 400hp...  sure it does.   OP built a stroker, asked about HP and got inaccurate info regarding manifolds vs./headers, which is the point of my replies.  His concern is losing 50hp and I bet he misses that number.

Fuel economy is another benefit that is overlooked with headers over manifolds.

Pick your parts, pay your money.

[57Fury440]

I ran fenderwell headers on my 57 Plymouth for years when I ran it in gas classes. I no longer race and swapped to hipo manifolds. There is a big difference in power. The biggest difference I would say starts to come in around mid range and up. The headers hade enough power difference that you can feel it. The benefit to the manifolds however is they are maintenance free and there is lots less heat under the hood. I actually prefer the sound of the manifolds with the dual exhaust system with the hemi mufflers over the louder headers. The bottom line is the headers make more power, even cheap ones.

[HP2]

Max Wedge factory manifolds would really be the best compromise of iron OEM manifolds and header high flow capability. Mancini sells reproductions of these for $1200 a set. These look nothing like the OEM HP units nor do they look like headers.
https://www.manciniracing.com/mamaxwema.html

But to the point of many, what difference does 20-50 hp mean to a street cruiser? Heck, even in a bracket racer, its a moot point as your number and ability to hit it is more important than  ultimate power. Only in a tightly regulated class does a few hp difference really matter.