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never used em,dont know much about em.
Got a 351m ina '79 4x4 F350, what manufacturers should i look at,a re there different kinds for different types of driving?
The old addage of you get what you pay for is true in the case of headers. I do not have any specific recommendations on which brand or model to buy, but I will suggest looking for one with the thickest tubing you can find, and thickest flanges. This will improve the headers durability, and sealing ability against exhaust leaks. Also, you need to decide on whether or not you want chassis exit, or fenderwell exit. Chassis exit are nice for keeping your exhaust tucked away, but bad for getting to things like starters, and you have higher under hood temps plus a higher chance of starter heat soak. Fender exits are nice because you have room to get at things, like the starter, and you get slightly lower under hood temps. The really bad things about fender exit headers are the fact that your tires can/will rub on them, and it makes running your exhaust in a way to keep tucked up out of the way more difficult.
I have had fender exit headers, I doubt I will ever run them again, unless its on the street or on a light duty offroad rig.
Different mfg have different port sizes besides tubes. Best to know what you have so you get a good fit. Car heads can have different size and position than truck heads. I would avoid the old fashion 3 bolt flanges. The newer ball/socket are good as long as the slip flange. You can also get shorties, which are easier to install and do not put the heat on the starter.
The ceramic coating (inside and out) supposedly traps more heat (inside) instead of allowing it to radiate thru the metal. Expect to pay dearly for a set of headers that is ceramic coated.
You gotta pay to play. I say do it right the first time and get ceramic coated, I didn't the first time and now I'm looking for new headers. As far as chassis exit or fenderwell I'm not sure, depends on what day you ask me.
I'd go with some chassis exit headers with the thinkest possible flanges and get them ceramic coated if money permits.
I thought about buying some headers and haveing them set off the be ceramic coated. This way would be a little cheaper than buying them from headman(for instance), and I have only heard the ceramic coating doesn't hold up for long(from the manuf. )
I couldn't afford the $500 and if it wasn't going to last, I figured I might as well save the money, I went with some cheap Os.
I had headers installed on my '74 F100 2WD and went through the same questions you are all posting. My exhaust guy (if you're around north Georgia let me know and I'll be happy to recommend him) suggested a couple of brands simply because of the thicker flanges and better designed tubes (for clearances). Hooker and Flo-Tech were his top suggestions (and he sells neither). He told me to purchase them and he installed them along with the Flowmasters and exhaust. Both of them have a full 1/4" thick flange.
Because he installed them, if my starter ever fails, he will replace it free.
I figured you couldn't beat that kind of deal.
Oh, one more thing, ceramic coated is not that much more..about $80 to $100..and is better long-term as well as helps increase performance by increasing exhaust temps.
Hope it helps.
Starters are a common wear item, headers will burn up GM starters because GM decided to the put the solenoid on the starter. I have yet to have an honest heat related starter failure that I could only point to the headers.
You didn't mention if the 351M was new or not, but you don't want to use the ceramic headers on a new motor, they need several heat cycles to make the coating stick.
What is the difference between an old motor and a new motor?? They both will spit out hot exhaust, or did I miss something in the only week of chemistry class I took?
Hooker headers do have an excellent reputation, but I would reconsider. The set that I got for my `78 F-250 with a 400, did not fit well. The flange hit the pass. side shackle, (Probably would be OK in an coil sprung F150) and the tubes did interfere with the frame. I ended up using hedman headers. Although the flanges are not as thick, they fit very well and the ball socket joint is pretty slick. I also had a set of summit headers. They fit also, not as well as the hedmans but way better than the hooker headers. For which ever way you go, the chassis headers are a major pain to get installed since the pass. side is such a tight fit. If you have an engine hoist, life will be much easier! Good luck!
L&L makes a good header. I installed a set on my 460 hot rod truck and have never looked back. 1/2" thick flanges with 14 gauge nickel plated runners. They are guaraneed for life. The fit was great. I have a set of John Kasses' alum. Super Cobra Jet heads and the L&L headers were a good match for these heads.
I do have a couple of comments. Adding headers will give you the potential to increase horse power but without going to a free flowing exaust ie dual pipes, cross pipe and with a performance muffler, the amount is not significant. If you plan on significantly increasing the hourse power, make sure that you get headers & an exhaust that will work best with the increase. It is possible to be too big as well as too small. That said, I think that the exhaust is a great place to start improving the engine's performance. Since an engine is basically a big air pump, it does no good to increase the engine's ability to take air in if the exhaust end of the engine does not allow all that air to exit the engine.
As far as the starter goes, get or make a heat shield, or get a smaller aftermarket starer. Fortunately, with a truck, there is plenty of room for the header not to be up tight to the starter.
Basically find a header that has a thick flange and the thickest gauge runners that you can. If you have problems with fit, take them back and look for another manufacturer.
You get what you pay for. I went through 2 sets of Heddmans
( I think they were about $150 new and the other set was used for $50 ) in about 4-5 years before they rusted through. Now I got a set of L&L's and they are great.