Cutting off exhaust ports?...

[cjshaker]

I've been brainstorming my parts list for a drag engine and began to think about any tricks I could pull to gain some HP. While thinking of the old Pro Stock 351C trick of cutting off the exhaust port and making a port plate to raise the exit location, has anybody tried cutting off the exhaust ports on an FE? Being that the exhaust ports are exposed so far back into the head, there would be a lot to gain in exhaust exiting and header design....in a non-shocktowered car of course.

I know there is a water jacket behind the outside of the head surface, but knowing a very good TIG welder, it would be possible to weld on a port with a much more friendly upward cant on an aluminum head. With a little extra weld built up, it could be ported nicely for a smooth port exit. Anybody ever tried or seen this done on an FE head design? Or am I just nuts (feel free to skip that last question).

[jayb]

Rather than skip the last question, I would like to confirm that you ARE nuts, just like the rest of us 

I did that raised port trick with a set of 429 SCJ heads back in the 80s, and I did hit the water jacket.  I was able to use the port plate to seal against the head with RTV and it never leaked.  So, I wouldn't be afraid to go for it if I were you.

I never tried it with an FE car because all my FE cars back then were shock tower cars, and when I got into the cammers several years ago there was no need to do something like that.

If you go forward, Doug, I'm sure there are some benefits to be gained in flow.  Make sure you post lots of pictures...

[cjshaker]

I'm going to study the head designs better and see where it leads me. Even if only the top part were cut away back to the head wall, there should be a lot to gain, as long as the port floor is also raised to match the top. Fenderwell headers are the obvious choice here.

Does anybody have a link to cutaway pictures of Edelbrock or BT heads?

[wayne]

I know I have seen it done maybe it was Clyde Detrick from garden city Michigan .

[TomP]

Why not just get the Dove heads with their raised exhaust ports? The Blue Thunders are raised .400" and that's enough for me. I experimented welding the top of the exhaust port on iron TunnelPorts and it did make some big gains. Made custom header flanges that had 5/16" threaded top holes and the header bolts went in from the back through the existing 3/8" threaded holes to clear the upward exiting pipes..

[cjshaker]

Tom, I'm not a big fan of Dove stuff because of their spotty quality issues. I've seen too many guys have to sink big money into them to make them useable.

I originally planned on using the BT heads, and may still. I have a few cars to choose from for this build and none are shocktowered, so I'd like to take advantage of smooth gentle radius fenderwell headers. Keeping an upward flow for the exhaust would make good sense, as long as it doesn't turn into an S shaped port.

I'm having trouble picturing how you did yours. Where did you weld? Since the upper bolt limits how far of an upward path you can take, I cant picture your upward flowing exhaust without getting into that S shape. I figured I'd have to do custom flanges or something available with the right port spacing.

I'm going to take a junk head first and cut the port back to the head and see what that leaves me. I can determine from there what is to be gained. I have also considered welding up the tops of the ports on a BT to have more room to raise the port exit even higher. It may be a case of more ambition than brains, but the cutaway should tell me more. Having a friend with a machine shop helps.

[Ratbird]

Doug, I found this cut away, not sure if it's what you are looking for as I don't really understand what you guys are talking about anyway...
http://www.race-mart.com/Edelbrock-EDE-60079.html
Also this one of a Felony head.
http://www.mustangandfords.com/parts/1309-survival-motorsports-new-fe-cylinder-head/photo-gallery/#3
And one more:
http://www.yellowbullet.com/forum/showthread.php?t=526863

Dave J

[machoneman]

Hey, you're onto something.

The exhaust pic seems to show one could whack off the entire top of the port and add a plate ala' the old 351C pro stock trick. 'Course, the bottom of the head's port  likely need to be filled in as well to make the transition to the new higher roof. That and eliminating most of the R-L-R-L angle of the ports to straighten them out, with the need then of course for a special header flange and new tubes.  In fact, I wonder if a 351C or 429-460 plate that is unported (small opening to allow special porting) would match up. 'Course a big hunk of aluminum bar stock and some machining does the same thing.  Very interesting! 

http://www.mustangandfords.com/parts/1309-survival-motorsports-new-fe-cylinder-head/photo-gallery/#3

http://www.pricemotorsport.com/html/body_high_port_exhaust.html

[KMcCullah]

Hey Doug here's a link to some iron head cross section pics. I think Bob Sprowl did them.

http://www.fordfe.info/HeadSections/Cross1.html

[cjshaker]

Thanks for the links guys. I went to my machinist friend to pick up some steel for making my new spring compressor. I finally got my OpenTracker roller spring perches and did NOT want to use the spring compressor I recently bought, so I'll be making one. I took an old C6 head to him to have him cut the exhaust port off. He said stop back in about a week.

I was aware of Barrys and Bobs cross section pictures but can't find any of the Edelbrock or Blue Thunder heads on the exhaust side. They always show the intake. They are useful for determining the water jacket location at the bottom, but not much else. The idea is to cut them down level with the lower head bolt boss or as low as is possible without getting into the waterjacket, and back nearly parallel with the valvecover rail. I don't really want to do a plate deal, which would require a bunch of CAD designing and machining, which I know nothing about.   That way I won't get into spark plug accessibility issues like the Cleveland and the Lima engines plate systems. They have angle milled slots for spark plug access and are bolted onto the head

Instead, I'm thinking more of welding on a fairly thick aluminum tube and keeping it tied (welded) to the head. Or more accurately, using the top portion of a rectangular tube by cutting off the bottom, shaping and angling it to fit the head while keeping an upward flow path and filling the whole bottom area with weld so it can be ported, then welding on a good flange for the header. I can fab the headers. The down side to this idea is that it adds a lot of aluminum material over the waterjacket making it less efficient around that area. Not sure what the consequences of that would be, but if it's all quality work, I'm thinking it would be negligible. I wouldn't even attempt this if it weren't for knowing an old friend who is a master at TIG welding and having a friend who owns a machine shop who is very good. Otherwise that stuff would cost me a lot of money to have done. While I've got years of practice and have my own MIG welder, I never learned to TIG weld.

Hmmmm, come to think of it, before I get too far into my idea....I better ask him if he would even consider welding them up for me.

[Qikbbstang]

     I've done some metal removal cut-aways with a die grinder here and there including around the exhausts that allow measuring but don't photograph well.  I can say you are correct to be concerned about the water jacketing on the outer edges above the ex-ports (the center above the ex-port is solid).  What I don't understand on your project is the area just under the valve cover seal to me is safe and free of water jacketing and you could vastly improve the port angle by working on that area and out to your new header.  From what I recall of the 351C ex-port mods they did not come out and aim all that high as if for the moon.

[machoneman]

Here's what a finished 351C port-plated exhaust looks like. Now that is a radically changed port only for a non-shock tower car. Amazingly, they were only good for about a 20-25 hp gain, this on a almost all-out Pro Stock styled engine.

See my December 2011 post

"Afret, can't tell you about FE header dyno tests and due to competition, Blair and others may not want to reveal same either. Long ago though some fellow racers with a high 10 second car did the 351C hi-port aluminum plate conversion that Ford's own O.H.O. tech back then stated was good for about 20-25 h.p. But they did so in a std. Maverick chassis and the custom header tubes, as required, had sharp bends right out of the exhaust ports, hence no e.t. improvement to speak of. The next season, they dumped the OEM underhood sheet metal, went the 1/2 chassis route and added nice new custom headers with at least 6"-7" of straight tube before the headers started the downward turn. They did then pickup IIRC about a tenth or .15 in e.t.

I've wondered too in high hp applications like SS just how much hp is hindered due to the need to keep the OEM inner panels in place and run sharp downturns, unlike Gas and Super Gas classes with those nice, easy turn headers." 

[cjshaker]

     What I don't understand on your project is the area just under the valve cover seal to me is safe and free of water jacketing and you could vastly improve the port angle by working on that area and out to your new header. 

BB, that is exactly the area I'm talking about. Parallel with the valvecover rail, and down to the bottom of the port....only as far down as is necessary to come to  the area of the port floor downturn. I should be able to avoid water that way and it should be cut back far enough to eliminate the downturn of the upper section. As I think about it, I may not even have to go down all that far. Maybe just enough to cut away the top of the port. It would be better to keep as much of the casting as possible to maintain integrity. The lower port floor downturn can be filled in with weld and just raise the port roof.

If I was good with photoshop or  something, I could post a picture of what I'm envisioning in my mind. When I get the head back, I can use cardboard and clay to fashion a crude idea of what I'm talking about.

Here's what a finished 351C port-plated exhaust looks like. Now that is a radically changed port only for a non-shock tower car. Amazingly, they were only good for about a 20-25 hp gain, this on a almost all-out Pro Stock styled engine.

I've wondered too in high hp applications like SS just how much hp is hindered due to the need to keep the OEM inner panels in place and run sharp downturns, unlike Gas and Super Gas classes with those nice, easy turn headers." 

Bob, that is about the angle I envision. 20-25 hp isn't bad for no other changes, in my opinion. At those levels, hp is harder to come by. NOT that I'll be pushing Pro-Stock level horsepower Realistically I was hoping to get into the 700 hp range and keep it reliable. Being able to use a little less lift and duration would really help in that department, and a good flowing exhaust coupled with Jays intake adapter with a tunnel ram would make for a nice breathing FE.

Actually, my only concern is whether or not the modifications could handle the high temperatures of the exhaust. I would guess that it will have to be a fairly thick tube and made of high quality aluminum. Something else I'll have to look into.

If the cut head looks promising, I can move this into the projects section. I'm hoping to be able to purchase a set of heads soon. It would be nice to see some real world examples and cutaways of the BBM heads also, but with the BT head already having a .400 raised port, that may be the best starting point.

[TomP]

On my Tunnel Ports that were cracked between the valves and had sunk exhaust seats it was just adding to the welding that was done. Otherwise i'm sure the $600 i paid then (late 80's) would still apply to just the exhaust port stuff. What they did was weld the floors of the exhaust in about and inch and around 1/2" deep. The tops of the outsides of the ports were welded up with about 1/4" extra material. The little ribs was gone, the whole port top was that level.  I raised the ports around 1/2" at the exit which is pretty much where the Blue Thunder ports are already and i'm going to raise those higher.
 You can't do much about the depth of the valve bowl.

 The Doves are a better solution i'd say. They can be bought with a variety of chambers and ports , it'd be worth any issues that might occur.

[MT63AFX]

My uncle's 57 Custom had a 63 406 in it and ran a consistent 13.10 with the standard, down turn exhausts (I don't remember if he had the shortys or not). He built a set of headers that were swept up then down out the fenderwells (inner fenders removed of course) behind the tires and went 12.51. This was on the old, hard 7" slicks. With all this talk of modifying FE exhaust ports I'd think if one could back-cut the flange (take a small wedge out of the top) and tilt the flange back to allow the exhaust more upward travel before changing direction we'd be surprised by the results, . On my uncle's 57 the headers came within an inch from the underside of the tops of the fenders. This kept the 'leaners' from spending too much time looking, "eww, ahh, ew, daamn", , RodC