Well, I don't know about going down hill, but I have a 292/375Y Block that has made 613.3hp/546lbft, and I hope there is a bit more in it before I quit with the testing.  My little 292/303Y made 463hp after the 2019 EMC, so there is still hope for those of us who still like working on these antique engines including the FE.  Joe-JDC

I have just picked up a couple of '83-'85 302HO 4V intake manifolds, and wanted to get some flow figures for them.  I had a Stock Eliminator racer ask about porting one, and I offered to do so as I had time.  He never followed through, so when a couple of the intakes came up on Craig's listing locally, I picked two of them up for $125.00.  The ports are tiny, the manifold is definitely a low riser, and just looking at it makes you wonder how the Mustang ran so well for the era.  I have flow figures for 292/312Y block 4V intakes, Lincoln Y blocks, 289 iron 4V, 302 4V, and all the FE's/429/460s/4.6modulars/5.0HO EFI/5.8 EFI from the last 35 years using a flow bench.  This little intake manifold only flows 140cfm average, and the '83-'85/E7 heads flow 169 cfm as cast.  Not a single runner flowed over 158cfm.  Here are a couple of pictures of the intake manifold.  Joe-JDC

There are still shops that regularly build old flat head engines with performance in mind.  I recently saw one that made nearly 400 hp which is very respectable for a flat head.  I saw another one that made 180 hp.  Both looked nearly the same.  I was trying to figure out just how much of that 722 hp was engine alone, and if I am close to correct, then it makes 485-500hp NA.  That within itself is an accomplishment.  Joe-JDC

Jay, is it possible to change your CNC program on the combustion chamber to have a more figure 8 around the valves?  Is there enough material in your casting for that?  As I look at your chamber, it appears possible.  Also if there were a vane around the intake guide it might help with stabilizing the valve, and speed up the flow.  Those heads are really tempting for a shock tower build.  Joe-JDC

That intake manifold also has the floors filled to match the epoxy in the heads and still manages to flow 490 cfm average.   I have been a proponent of porting any intake manifold to flow at least 110% of the head flow, and for performance usage, I try to get the flow up to 120-125% of the head flow.  When bolted together, the heads don't normally drop in flow this way as a result.  I have flowed hundreds of heads with intake manifolds over the last 29 years to verify the process.  I also work very hard at balancing each runner's flow so that each cylinder makes close to the same power and torque.  Makes the carburetion easier to jet, also.  Joe-JDC

Thinking has changed from the '60-'70s on many things fuel related.  First, you may have to enrichen the carbs primary jets to get the benefit of the 10% ethanol gasoline used today.  If you get a pinging on acceleration, then you need to slow down the advance curve or jet up the primary jets to compensate for the ethanol, or both.  Nearly every carburetor I have dyno tested over the last 10 years or so have needed the jetting increased on the primary side.  That includes QF, Holley, Edelbrock, and Pro Systems carbs in every size from 500 cfm to 1250 single carbs.  Joe-JDC

From a Tunnel Wedge users point of view, I found that the Ford TW needs to be balanced in flow front to back.  Your graph on the carbs using different airflow quantities proves my point.  The rear intake ports are more straight and flow quite a bit better than those front ports.  I also found on my own engine that you need a spacer to give the plenum more depth so that the air can turn into the ports easier for higher rpm.  If the carbs were not keyed 1:1 and run progressive, you will have a mismatch in fuel ratios.  As for the TFS CNC heads, ALL of them go turbulent and flow stagnates at lifts varying from .580"-.630" lifts out of the box.  With some tweaking I have seen 364 cfm without making the ports significantly larger in volume, all with stock valves.  With a stockish TW, the flow usually comes in around 365cfm average, with the rear ports near 390 cfm, and with a simple cartridge roll will flow 400 cfm.  With 320-330 cfm heads, the intake needs to flow at least 400 cfm.  Also, did you increase the timing with the 110 fuel to find where the horsepower starts to fall off and back it off a degree or so?  Sometimes those heads like 36-37* depending on the ignition being used.  I just did an intake and OOTB TFS heads for a 447 here locally that used a 220* camshaft and made nearly the same horsepower as this one with a Holley Street Dominator and 750Holley.  I know dynos are different, but this dyno is close to those at EMC at both places in Ohio.  Joe-JDC

Manifold no longer available.  This is a Dominator flanged Victor 427 EFI intake manifold with the injector bosses in the runners.  This intake is injector ready.  Porting it and ordered fuel rails for my own project 530FE.  Joe-JDC