FE Power Tunnel Port Cylinder Heads

[Tunnelwedge]

When Sammy sold the Red Rocker TP on BJ he said it was too fast for him. He did.
I would bolt them puppy's on my geny no problem. Well other than I don't have the price of admission.
If you want me to test them on the geny I could. 
You need your own block.
Great stuff Jay.

[1967 XR7 GT]

Previously, I had asked, what valve sizes will be used on the TP's ? jayb replied up to 2.300" int & 1.750" exh.  I don't think a 1.750' valve will fit with a 2.300" valve though, as seen with the head on the bottom, a cast iron Tunnel Port head provided by Brent, with 2.250" int & 1.750" exh. 

Head at the top is jayb's Tunnel Port, which has a modern chamber design something like his RESE heads, which is designed for a 4.250" bore. Chamber has already proven to fit a 2.300" int with a 1.675" exh.

Also, jayb says he is shooting for around 68cc's chambers on his TP's and 
I think the cast iron TP's are something like 88cc's.

Here are jayb's flow numbers from his RESE Heads that I thought to
compare to flow #'s of ported cast iron TP heads that Brent provided,
and I know it's apples & oranges, regardless it was an interesting
comparison.

 

These flow numbers are from a set of cast iron Tunnel Port's
that Bret had up for sale for comparison: 
Ported/Assembled Tunnel Port Heads

.100      80.54      58.49
.200     159.49     105.62
.300     238.48     146.24
.400     300.82     189.52
.450     320.87     192.76
.500     341.37     197.62
.550     356.53     199.89
.600     360.98     204.10
.650     368.11     207.34
.700     374.35     215.44

[jayb]

2.300" intake and 1.75" exhaust will fit the tunnel port heads.  Valve spacing on a 427 head, tunnel port or medium or high riser, is 2.100".  I agree with Brent though, I'm not sure it is necessary to go to a 2.300" valve to use the flow capacity of the intake ports.

Valve spacing on my SE and RE heads is smaller than the 427 spacing, at 2.050".  This is so that it is easier to use the heads on a 390 stroker or 428.

The chamber in my SE and RE heads is better for flow than the tunnel port chamber I designed.  The reason is that the valves are moved towards the intake side of the head, making them closer to the center of the bore with my SE and RE heads.  This allows for a more gradual turn to the deck on those heads than is possible with the tunnel port design, or any FE design for that matter with the stock valve location.

Also, keeping the chamber small allows for decent compression with a flat top piston.  So you won't need those extreme domes that are seen with factory tunnel port pistons.

[Tunnelwedge]

I believe I could bolt Jay's TP heads on my engine and it would run excellent using my 4.250" bore engine the way I do.
It's a low compression dish piston tight quench with a 3/4 race cam and runs on anything from a gas pump stump puller.
I could even use all my valve train stuff. Might even get 10 miles to the gallon.
I could not bolt real TP heads on and expect the same performance.

[Tunnelwedge]

427 NASCAR Tunnel Port Blueprint Specs

[jayb]

I got a valve job and bowl cleanup done on one chamber in order to get flow numbers, and I was pleasantly surprised by the results.  Especially the exhaust port did better than I thought it would.  I had tweaked the stock design just a little bit, and it seems to have made a significant difference.  Still not as good as my SE heads, but better than a lot of FE exhaust ports that I've seen:



After getting the head back from the shop I checked the chamber volume, and this was also a surprise, it was much lower than I expected at 55 cc!  I will have to make a modification to the chamber machining program to get a little more volume.  The upside there is that it can only help the flow.  Pictures of the chamber and the port cleanup under the valve are below.  Please excuse the yellow grease in the chamber and near the valves; that is left over from cc'ing the chamber:

[Mark Bliss]

That is a pleasant surprise Jay! And judging by the images there is a good bit of improvement available with a little "light massaging." Maybe an easy 15-20 CFM at least on the intake pocket area with no harm, maybe even improvement to velocity.

In the chamber, just by visual judgement, I might suggest considering laying back/smoothing the spark plug opening area mildly.
It just looks shrouded with a little too much room for "spooks and ninny's" to hide.
Not much, just a little "opening and smoothing" of the area.

Just a casual layman's observational view....
I am no engineer; I just play one on TV.

[frnkeore]

How wide is the X axis of the chamber?

[jayb]

How wide is the X axis of the chamber?

It is 4.25" wide, 2.125" radius.  From the center point of the chamber, around the exhaust valve the radius might be just a bit larger than that, because in order to do the 5 angle valve job the cutter had to take a bit off the chamber; you can see the radius created by the cutter in one of the pictures.  Fortunately any FE head gasket for a stock bore will not have a perfectly circular profile anyway, so that little bit will not cause an overhang of the head gasket into the chamber.

[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

[jayb]

Sure Joe, I could change the chamber as you suggest, but as it is the chamber is too small.  I will have to look at what's required to enlarge it by 12cc or so before I can think too much about changing the shape...

[TurboChris]

Mmmmmmm subscribed.

[1967 XR7 GT]

Jay, did you have the 5 angle valve job done on the seats ?

And the valves, why not 5/16 stems like on your FE Power Cylinder Heads, instead of the 11/32 ?

   - The guides have been changed from 3/8" stem to 11/32" stem.

I got a valve job and bowl cleanup done on one chamber in order to get flow numbers, and I was pleasantly surprised by the results.  Especially the exhaust port did better than I thought it would.  I had tweaked the stock design just a little bit, and it seems to have made a significant difference.  Still not as good as my SE heads, but better than a lot of FE exhaust ports that I've seen:



After getting the head back from the shop I checked the chamber volume, and this was also a surprise, it was much lower than I expected at 55 cc!  I will have to make a modification to the chamber machining program to get a little more volume.  The upside there is that it can only help the flow.  Pictures of the chamber and the port cleanup under the valve are below.  Please excuse the yellow grease in the chamber and near the valves; that is left over from cc'ing the chamber:

[jayb]

Yes, the 5 angle valve job was done on the seats.  I picked the 11/32" valves because the guides for that size valve that fit the heads were available off the shelf.  No reason a 5/16" guide couldn't be used, if you could find one, or have some custom guides made.

[PLemoine]

If someone has a pair of used trick flows they want to sale to upgrade to these I'd be interested. Jay's heads are awesome but out of reach for me right now.

I’ve got a new set still in the box if interested.