Headers improvement?

[morganater]

I know this may not be the best place to be asking this but i was wondering if you guys thought that headers would add a ton of horsepower to my engine. I have a 1970 460 with Edelbrock timing gears, a cam, aluminum intake and carb. It is running though stock exhaust manifolds and I am going to order some block-hugger type headers becuase they are the only ones that will fit wth my power steering, etc. Will these be a lot worse than some Tri-Y types? there is no way i wll be able to get in some tri-y headers , the heddmans or the L&L's availbale for the swap so I am forced to go with these: http://www.sandersonheaders.com/pagesby ... /ff461.htm

How much horsepower do you think these will give me, I am just looking for more supporting opinions, thanks.

[TheImpaler]

When they're working properly, (meaning they have no leaks), headers are nothing but awesome. They improve power, performance, and sound.
However, when you want to work on your motor or when you have to replace gaskets, they can be the worst thing any time ever.

That said, the block huggers look to be more easily maneuvered than most, so you won't have as much of a problem. Keep in mind you'll have alterations made to your existing exhaust.

-Patrick

[morganater]

Yeah i'll wrap them up real nice so I dont go through a starter every month And i am re-doing my exhaust anyways, 2.5 straight from each header through some short glass packs then out the sides in front of the rear tires. will i lose or gain HP with this setup, dont flame me on being REALLY loud tho

[TheImpaler]

You might consider a jet-hot coating (ceramic) as opposed to the header tape. While I don't have personal experience with the header wrap, I have not heard good things.

As to your exhaust choice, sounds good! Make sure to get some 3" chrome tips on there for looks and sound. (The longer they are, the more "deep and rumbly" you'll sound). I do also like FlowMaster 40's. Loud as sin while still sounding clean.

You'll definitely pick up some HP with this. I'd say at least 20-40, depending on your motor and current exhaust.

-Patrick

[morganater]

Yeah i mean my motor has a bunch of intake mods as i stated earlier, so I am assuming headers and a freeer flowing exhaust will free up some HP that I dont have right now. I have a 2.25 dual exhaust with some FATTY mufflers, i dont even know the brand, but they look like big heavy mufflers, . I am wondering if I get 2.5 that i will actually LOSE HP becuase I am losing back pressure?

[68F250]

That's an interesting question that I hope nobody blows off.

My experience with headers is you lose some off-idle response and torque but you get it all back and then some higher up in the rpm range. I really think there is a point of being too big where you lose the velocity in the pipes at part throttle and cruise conditions to where you have to put your foot into it just a little more.

Barry

[FORDification]

I know many people live by the addage that "bigger is better", but in many (most) cases that's not true. You CAN get too large in header tube and exhaust pipe diameter. A street-driven vehicle has to have SOME back pressure....you just want to decrease it, not try to completely eliminate it. That is where the term "tuned headers" comes into play. The manufacturer has done extensive testing and determined the optimum tube diameter and length for a specific RPM range and use. Street headers will typically have smaller diameters and shorter unequal-length tubes vs. street/strip or full-race headers with larger tube diameters and longer equal-length tubes.

Here are a few links with some good info on the subject of header design:

http://www.headersbyed.com/bildbetr.htm
http://www.mustang50magazine.com/techarticles/29618/
http://www.sandersonheaders.com/letsgettech3.htm

[crazy larry]

I'm running headers, dual turbos, and a 2.5 inch exhaust all the way out, and according to my vacuum gage, i have a restrictive exhaust. I, in my opinion, do not think a three inch exhaust would be too much. and i can attest to the fact, that when i was running around with open headers, i can for a fact state that i had more seat of the pants power than i do with the exhaust.
use permatex ultra copper on your header gaskets, and i highly recommend STAGE 8 locking header bolts. also have the dead soft aluminum collector gaskets with stage 8 lockers on them, and they've stayed tight also.

[flyboy2610]

One other point which a lot of people fail to consider is that headers WILL raise your under hood temperature. You will therefore be sucking hotter air into your carburetor, and hot air does not permit as dense of a fuel/air mixture as cooler air will.
One thing you don't want to do is run headers with an open element style air cleaner. I know, a lot of people do just that. But consider what I just said. You are just sucking hotter air into your carb, and losing power as a result of a lense dense fuel/air charge.
If I were going to run headers, I would retain the original air cleaner and run some flexible hose or tubing to the front of the vehicle to draw in a nice cool air charge. Then you get the added performance headers can give you, and you do not sacrifice the cool air needed to get a good fuel mixture.
Just my 2c.

[TheImpaler]

In regards to headers decreasing performance, I understand the following to be true:
Our old trucks are not fifnely tuned racing machines. That said, you have a bit of room for error in choosing your exhaust system, though that doesn't mean you should just slap something together.

Headers will, overall, help your motor. We can all agree on this. Where you will have different opinions is in pipe diameter, length, exit point, bends, etc. I would consider your compression ratio - if it's a truck 460, you can get away with 2.5" pipe. If it is a higher compression car motor, you might like to use 3" pipe. As well, if you plan on rebuilding the motor for performance in the next few years, you might as well get the 3" pipe now.
You shouldn't have any problems with "back pressure," as the 460 is a big motor that needs to breathe. In fact, back pressure isn't something you want at all, it is just a necessary evil in preserving exhaust velocity. (The charge of the gases serves to push out gas farther down the pipe and pull gas from the engine side of the pipe).

For reference, my buddy has a 400 Chevy Small block, all roller setup, in his 70' StepSide. 3" pipes all the way back and this baby needs every bit of it...
In my truck, I have a warm 390 with 2.5" pipes. Sound would benefit from 3" pipes, but until I get a hotter cam in there, I can't pull the revs to justify 3".

That said, I would run 2.5" pipe with glasspacks if you aren't planning to rebuild the motor with higher compression and a hotter cam. If you plan on making more changes to the motor, however, I would use 3" pipe and FlowMaster 40 mufflers.

Just my thoughts...To be taken with a grain of salt, as I am still learning.

-Patrick

[morganater]

Yeah so i guess the primaries on those Sanderson headers I am looking at are freakin 1 7/8 ". That is an awful hefty size for this semi-mild motor I am running, and seems like I will lose a lot of low-end power. I still don't care, I want the sound of the headers. I hope i will get some good HP, maybe only with the cutouts open, i don't know.

[TheImpaler]

Yeah so i guess the primaries on those Sanderson headers I am looking at are freakin 1 7/8 ". That is an awful hefty size for this semi-mild motor I am running, and seems like I will lose a lot of low-end power. I still don't care, I want the sound of the headers. I hope i will get some good HP, maybe only with the cutouts open, i don't know.

By that logic, the cutouts were do even more harm than good. If you're worried about the headers being too large and free-flowing, you will WANT the exhaust to be at least semi-restrictive (or rather, capable of maintaining gas velocity at the expense of having some back pressure).

Anyway, I think you'll be fine with those headers - it's up to you and your plans if you want to run 3" or 2.5", though.

Let us know what you decide!

-Patrick

[magnethead]

On our truck, the 454 has 200,000+ origional miles on it, we added hedmans, and theres no question they helped even that wore the heck out motor develop power. With all those mods on your motor, i'm guessing 40 gained at the flywheel.

As for exhaust diameter, you WANT Backpressure. If you look on the big honking cummins powered duallies, they have 4" exhaust (at least most do). Why? They have a high exhaust velocity since diesels run off pure block heat and high compression.
Meanwhile, some of those mini-cars (honda, VW, ect) have dinky 1" and 1.5" exhaust pipes because they run such low compression and so few cylinders it aint funny (or maybe it is...).

I think 2"-2.5" Is pretty good for a 390, our dually (again with headers) has the stock 2.25" exhaust still.

[Comet]

You shouldn't have any problems with "back pressure," as the 460 is a big motor that needs to breathe. In fact, back pressure isn't something you want at all, it is just a necessary evil in preserving exhaust velocity. (The charge of the gases serves to push out gas farther down the pipe and pull gas from the engine side of the pipe).

That said, I would run 2.5" pipe with glasspacks if you aren't planning to rebuild the motor with higher compression and a hotter cam. If you plan on making more changes to the motor, however, I would use 3" pipe and FlowMaster 40 mufflers.

Just my thoughts...To be taken with a grain of salt, as I am still learning.

-Patrick

This is exactly what I was going to say. Keep in mind the truck 460s were built for low end grunt, so losing a little down low to gain on the top end is ok, IMO, especially if you run an RV cam. The biggest opportunity for HP gains on these is a better breathing exhaust and better flowing heads. I'm going this route in the 460 I'm building (eventually ) and running 3" exhausts. This (and some other tricks) is what was recommended to me from a well respected Ford builder in my area that is world re-knowned (no lie) for his head port work. He just got done competing in Popular Hotrodding's Master Engine builders competition. It's an invite only event, but I don't know where his team finished.

[morganater]

Yeah i really wish I had the time/money/maybe the knowledge to self-port my heads. I even have an extra set laying around from my blown up 429 that I could use. I don't know how to do this though, so im out of luck. My friend has a 1977 Dodge short bed single cab 2wd with 4.10s and a 440 with an intake, cam and headers and he can nudge me out right now in a race and its really annoying. I want to get the headers to beat him and also to have the badass sound like his. I am mad that the 460 is constantly referred to as the dog motor of all motors, though.