Getting ready to weld up some exhaust and wondering about headers. I'm familiar with the performance advantage of headers on OHVs but wondering if the performance benefit is worth the usual inconveniences on a flathead. Seems like by the time the exhaust makes it way across, down and through the block some of the advantages headers offer might be reduced. Talkin' a street car with mufflers, stock cam.
Most of the headers for flatheads do little as they don't have much in the way of equal length primaries or collector length and diameter.Something like this would be a different story:http://www.ebay.com/itm/Flathead-4-...r_Truck_Parts_Accessories&hash=item3cc15c359f Like the early Pontiac headers they incorporate a splitter for the two center cylinders,compare these to the more common flathead design here:http://www.reds-headers.com/html/flatheads.html
not sure who fab'd these under car tubes....got them back in the 80's from an old guy....hoping Jeff will fab up a new set...we need to find out if they will clear a stock wish bone or what....
stillrunners, If those headers would fit on my stock '47 Ford Tudor I would love to buy a set if somebody would fab some up. Thor
If you read JWLs fantastic book, you will find that the difference in performance on a basically stock engine between stock manifolds and headers is minimal, certainly not worth the expense or hassle. This should be mandatory reading for anyone with a flathead. Hundreds of dyno pulls, all documented.
I disagree. the flathead has 12+" of the exhaust gasses running together, trying to split them back up after the fact will not help you at all. once the pulses are combined you cannot split them again....
A small gain would be a good thing. I vote to run em. And what ever you do, leave the mufflers off! Flatties are not so loud that you can't run em with straight pipes.
As already stated, headers don't help much on a flathead because the restriction is in the block, no down stream in the exhaust system. If you are looking for power, a quality porting job is much more critical then headers. Good Luck
Mine is a 60hp, and I'm pretty sure I read that somebody made a divider you could shove in the block.
Well since we let the Genie out of the bottle here is an interesting discussion:http://www.fordbarn.com/forum/showthread.php?t=23241 John Bradley ran port dividers aka "splitters" guess he might know a thing or two about flatheads. Notice the headers in this test: http://www.youtube.com/watch?v=dYH1TgYhx84 and this one:http://www.youtube.com/watch?v=_-IevaW2lLY Both are pulling some good numbers.
The splitters in the article mentioning Bradley are a completely different concept creating a barrier up between the valves, not dividing the common port all the way. Olds type ports, similar to those on some British engines, were separate except for the last bit, and on those engines a carefully shaped baffle from paired headers effectively separated the cylinders all the way.
Here's a link to one excellent post: http://www.jalopyjournal.com/forum/showthread.php?t=332905&highlight=exhaust&showall=1 I'm pretty sure that if you use Vergil in advanced search you'll find some more of this cutaway info. Flatdog was one of the truly great developers and his posts will churn up some good brain food. FD believed in heavily slanting the end port exits for a smooth transition from the angle of the last part of the port. Ron H describes a totally different approach, cutting ports toward ends of block and adding a fabricated baffle, in effect eliminating the last curve and making a straight shot out.
The Jalopy Journal
