Mike,

It sounds like 1 5/8" primaries on a supercharged set up will be alright for about 485hp.  That's what Hoosier has.  I wonder if he's pondering larger primaries now?

If you have the equipment, and a track close enough, you can go to test n tunes and do the same testing for the headers, probably at much less cost.  You can make the headers variable length and keep making runs until you figure what works best.

Lawrenceville, GA

In the "old" days we used to put a long collector tube, painted white on the headers. Run a few laps to really heat them up real good then cut them off at the burn marks. Run them again and keep doing this until the hottest part of the exhaust exiting is at the very tip of the collector. Old guys said that was the "sweet spot" to make them work their best? Chuck in NH

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

I thought about something like this, but we don't have a track anywhere near here.  Likewise, the nearest dyno is not close.  There is a chasis dyno in town, but I will have the engine done a long time before the chassis is ready.  I am still leaning towards the 1-5/8 primaries, based on comments by Gord McMillan in Calgary, Alberta who has built a number of supercharged y-blocks.

This is how our Twin turbo headers looked at the Phase One set up.

And this is how our Single turbo headers looked at our Phase Two set up.

The Phase Two gave us 330 hp and 465 ft lbs with that too small Rajay turbocharger wich generated over one bar of exhaust back pressures to slow down our engine.

So, use what you can get to fit as an headers, and they will work with enough boost onboard

 Seppo from Järvenpää, Finland
www.hollowheads.net (just click the hole in the head to proceed)

   Mike, no, quarter mile times and ET's. I'm not going to pull the engine oe spend money for dyno time at this stage. We did that when I picked the motor up from Mummerts. I can tell you this, we tried a set of Jerry (Christianson's) street rod headers on the motor. They were too small and WAY too long for this motor, but it picked up 50 ft lbs at 3200-4000 over the manifolds! 

Frank/Rebop

Bristol, In ( by Elkhart) 

Seppo.  Thanks for the pictures.  Your Phase II setup looks great and the header design is definitely an improvement over the Phase I setup.

I haven’t performed dyno testing specific to header tube sizes on the Y but do have it planned in the near future.  Collector length testing has been easy enough to perform but doing the various tube size testing requires headers for each tube combination; the lack of headers representing all those combinations has been the hold up for that.  For the FE’s, I’ve been able to experiment with tube lengths by having a removable collector and using extensions of various lengths to extend the overall tube lengths.  I am slowly collecting Y headers of different configurations and will simply test all these on the same normally aspirated mule engine when time permits.  The problem with this kind of testing is that it will find the optimum header combination for the engine being tested which will not necessarily be the best header design for another engine if any of the engine parameters such as displacement, compression ratio, camming, rocker ratio, head work, intake manifold, etc. changes.  If it was definitive, there would be a single formula saying what the header design should look like but there are simply too many variables.

Lorena, Texas (South of Waco)

Another option on collectors if running them open all the time (race car) is an angled cut at the end of the collector after determing the optimum length which further aids the transition of the exhaust flow from the collector itself.  If running headers capped up to a full exhaust system without thoughts of them being uncorked for an occaisional ¼ mile blast, then optimizing tube diameters, lengths, collector sizes, etc. does not become as critical.

Lorena, Texas (South of Waco)

Frank,

This tells me quite a bit because you indicated earlier that you are running a motor that is essentially stock.  I presume it is not supercharged either.  If your motor needs more flow through the headers, I probably will need even bigger headers with the supercharger.  What heads are you running and are they stock valves?  Stock cam lift and duration? Are your heads ported?  What size carb? I just wonder how your setup compares to mine.

Mike K

Ted,

I thought that if I tackled the dyno testing with various header tube diameters, I would not try to find existing headers, but simply fabricate some generic headers for the tests.  That way, I would not have to worry about making them fit the car body.  Your idea about different lengths of extensions makes more sense than what I was thinking (a Saws All) and would preserve the header tubes for collector experiments.

I agree that the data would only show what that particular engine liked, but some generalizations and extrapolations could be made.  If you ran the tests on a normally aspirated engine and I ran them on the supercharged setup I am building, the tests would provide a range of data that might be extrapolated or interpolated to other engines.  At least some principles might be established.

I have no experience in dyno testing.  How much effort does a run require, once the engine is plumbed in and connected?  Is this a readily repetitive process (assuming the engine is running ok) or is there more to be done between runs than changing the headers?  I am guessing you have a dyno in your shop.

Mike K

Mike,

      It is blown. It's a reproduction F code, using 471 heads. I built a repo intake from a standard B manifold, uses an Engle cam with Ford blower cam lift and duration figures.

     The motor made 377 hp on the dyno in California. The motor was built by John Mummert in 2003 or 4.  So far the best times have been a 13.70 at 105 mph through the mufflers on 215 radials in pure stock form (calculated to be 344 hp to the rear wheels) and a 13.55 @ 105 on slicks at EXPO this year before I broke the retaining straps on the driveshaft by leaving at 5000 rpm. I built the car out of curiosity, wanted to see just how strong the 300 hp F codes really were. The answer is pretty Dang strong for 1957! The car is at present a three speed column shift with 4.56's on the strip, 3.25's on the street.

Frank/Rebop

Bristol, In ( by Elkhart)