Do block huggers effect hp

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maca

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I have been looking at block huggers as my engine bay room is a minimum. I have heard they can effect hp because of poor flow but they look like they should flow well.
Any on had any experience with these and hp loss
 
mderoy340 said:
360 exhaust comparison shorty's do pretty good.
http://www.hotrod.com/how-to/engine/mopp-0307-mopar-crate-engine-exhaust/
Click to expand...

Unfortunately they don't say which 360 manifold was used for the test?? The 360 manifolds shown in the pics of this article are some of the smallest 360 manifolds made. As opposed to the 360 manifolds that I sell which have an exhaust exit hole the same size as the HP 340 manifolds.
As you can see in this pic below, the 360 magnum (the correct one) has a humongous exhaust hole compared the 318 and the "regular" 360 manifolds.

treblig
 

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Here's the Magnum on a different engine and test.
http://www.hotrod.com/how-to/engine/1406-comparing-headers-and-manifolds/

Don't get me wrong, I think you offer a good alternative for those that choose to run manifolds. I swapped out my 73 340 manifolds (which are the worst flowing of the 340 manifolds) and dropped in the Summit 1 5/8 headers everyone knocks and got a good bang for the buck hp wise.
 
mderoy340 said:
Here's the Magnum on a different engine and test.
http://www.hotrod.com/how-to/engine/1406-comparing-headers-and-manifolds/

Don't get me wrong, I think you offer a good alternative for those that choose to run manifolds. I swapped out my 73 340 manifolds (which are the worst flowing of the 340 manifolds) and dropped in the Summit 1 5/8 headers everyone knocks and got a good bang for the buck hp wise.
Click to expand...

The 360 manifolds shown in the web site may or may not be the "large hole" 360 manifolds that I'm taking about. There are two different 360 manifolds that look exactly like the ones in that test. Without seeing the manifold casting number there's no way I can tell if it's the large hole 360 magnum because Mopar used the exact same shape manifold for both the large hole (2 1/8") and the smaller hole (1 7/8"). Besides measuring the exit hole, there's virtually no way to tell the difference unless you look at the casting number on the manifold itself. I can't see (make out) the casting number at the web site you posted.
Just like the other web site posted earlier, it say's they used a 360 manifold but the one shown is NOT a large hole manifold. I have one of those right now and I know the exit hole is small. I know you're not poking at me...LOL!! It just makes me angry when these Hot Rod articles don't tell you the casting number on the manifolds they test. I mean if they told you the casting numbers everyone would know what to do, or what not to do, RIGHT?? But without the casting number the test is worthless because I have bought many, many, many of the so called "magnum" manifolds. Some have a large hole and some don't. They look the same on the outside (casting shape) but believe me....there are BIG differences. The magnum manifold was produced from 1991 to somewhere in the late 90s, very few of them had a large exit hole. The driver's side and the passenger side "magnum" manifolds both have a twin that does not have the large hole. There are many, many more of the EVIL (small hole) twins than there are large hole.
I can go to ebay right now and see two magnum manifolds that look exactly alike but one will have a small hole and the other will have a large hole.

Fellow Mopar enthusiast!!!
Treblig
 
depends on the engine
a 325 hp engine will gain 10 or 12 hp with shorties or headers
a 500 hp engine...well that's gonna give you something worthwhile
 
Thanks guys
At face level it looks like the small hole hugger are close to stock but the large hole ones would flow much better. If I had a cam with lots of overlap I would need the longer pipes regardless of shorty hole size. I could be wrong but that's what I read out of all those articles. I think the carby cams have more overlap than the Efi cams too.
 
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