Umm.. not on any stock Ford exhaust ports, they don't. A split pattern cam with tighter LSA will almost always help scavange the weak flowing exhaust port and produce more peak power. It'll typically be a narrower power band.. but the cam will come on quicker. Mostly just depends on how the drivetrain is set up and how you intend to drive it, is all. Of course some heads need more help than others.. but Fords are generally considered to be weak in that area by design. No big secret there. Case in point is the 429 SCJ in my old '71 Torino GT. When moving from a Comp Cams solid stick of around 232 duration @.050 with 112 LSA to a Crower solid having just under 230(228 degrees, IIRC) and a tighter 108 LSA.. the car picked up almost 2 tenths in the quarter and forced my stall speed almost 50 rpm higher off the brake than the previous cam did due to the extra mid-range torque gains. The lift for both sticks was almost identical at .570'ish. After almost 3 hours of tuning on the chassis dyno.. the engine made 22 more peak horsepower and I picked up almost 35 ft/lbs to the rear wheels at just over 2,800 rpm. Needless to say I was shocked that the motor made more power with simple LSA changes and all the "old time advice" had been spot on. Funny enough, I received most of that particular SCJ head porting advice from a multiple(7 time?) world record holding off-shore power boat racing shops head engine builder. Lucky for me we were laying sewer main in front of their shop and we got to making small talk about my Torino over the few weeks time we were working there. Turns out that he had a '68 Torino GT with the 428CJ and had built hundreds of big FE and 385 series motors in his earlier years as a mchinist/head porter. I thought I was in heaven having finally found someone at the time who wasn't a Chevy guy! lol While we talked about my various stages of porting advances.. he would often be hand forming each piston domes blank via grinder and mocking/remocking the crank assembly more than 10 times per hole on the 500+ ci hemi bullets they used. Basically, and as many know, those old 385 series heads have poor'ish exhaust port floors/SSR config's(nearly exact to 4V Clevelands) and anything you can do to increase scavanging and improve the heavily lopsided I/E port flow ratio will help those heads. Especially on smaller ci engines with less than ideal compression ratios. And sometimes even at the slight expense of intake flow if need be. This improves pressure recovery in the engine which can help response and peak power to go up in every build I've ever done, seen, heard, or read about. The way I see it is if MAF/EFI calibrations could more easily deal with tight LSA cams?.. there would be TONS more grinds available for ALL motors. On carb'd motors they simply grind it that way.. because the carb will allow it and they can make more power in the process. That's why you won't find wide LSA cams on short track motors either since you'll just give up peak power and widen the torque curve with looser LSA. Just my thoughts and experience so far with various Ford heads.
No cam designer tries to achieve a particular LSA. LSA figures are just a calculation that can be made after the designer gets the valve events he feels meets his requirements. It's more appropriate to consider the valve overlap period. Carbed engines (especially stock-headed Ford carb engines, LOL) like an exhaust-biased cam with more overlap whereas the EFI engine needs less overlap so that intake manifold pulses created by large overlap don't confuse the computer. Edit: In one of David Vizard's books he has a whole chapter on how to calculate cam requirements based on vehicle usage, components used, etc. Using his formulae it looks like my cam is almost perfect for what I want it to do. To get it perfect I should replace the 1.6:1 intake rockers with 1.7:1. So if any one wants to go halves on a set of Scorpion 1.7:1 roller rocker arms give me a shout. LOL
Y'all can theorize all you want, but I know what I've tried. The F4TE, B303 and the Z303 work better with carbs than EFI does. I've run these with ported(exhaust side only) E7's, GT40's and Canfield heads. The F4TE has virtually no overlap and the powerband runs from idle to 6000 in a 302. Great cam for all around daily use.
So by porting the exhaust you eliminated the stock heads requirement to hold the exhaust valve open longer. And, obviously, exhaust flow is not an issue with the Canfields. But you're right, on a carbed engine low overlap can give broader, flatter power/torque curves at the expense of peak power and torque. And that works great on the street.
Of course we're splitting hairs here and I'm not trying to disagree that the alphabet cams can't work well enough. This year alone I probably saw and talked to more than 20 guys who run them in various rides and they can run. And though I don't do it as often as I used to(a wife and kids will do that to you).. I do actually ride around with specific purpose do participate in "unregulated driving" late at night. But as you mentioned with the above.. the motor will feel flatter/broader with wider LSA cams. Now that's probably perfectly fine for most that have a milder build with "all-around gears" and/or an overdrive. But the guys who run custom cams will tell you that you are leaving quite a bit of the fun factor on the table with those flatter broad range cams. For a daily driver that you rarely rev or race?.. great. I drive em' like I stole em' most chances I get and haven't used a wide LSA cam in any of my engines for years. Personally speaking, my "street cam" power band tastes are more along the lines of 3.70'ish gear running me around at typical rpm ranges between 2,000 and 5,000. Any less or more than that and I'm either sitting still or really letting her off the leash. Realistically speaking.. about the only time my engine see's less rpm than that is when I'm idling at 1,200 rpm. So, in my case.. a narrower peakier midrange cam will be funner to drive And I don't usually theorize much unless that's specifically mandated for the conversation. Although ego's should be set aside a bit to adjust everyones learning curve.. I been around long enough to know a few things about engines too. I also have many friends with much more serious hardware than most here, including myself, and spend many months of my life either building, help building, riding around in, or just plain hovering around it like a fly over doo-doo each year. Been that way for most of 30 years now and I hope to make another 30 if I'm blessed enough to have the chance. So, after all that.. try this. Call 3 different cam companies and put in for custom grind requests to see what they come up with. 114 LSA? On stock type port architecture, 3 x out of 3 times you'll end up with tighter LSA cam spec's over the "off the shelf" grinds because they have been proven to work time and time again over the "works on any V8 engine ever made" cookie cutter patterns. And that's EXACTLY what these cams are considered to be by the guys who test and grind them. Basic all around type starting points.. that work well enough for basic all around type power plants.. driven in all around type driving situations. Without a doubt.. they are a compromise at best. Other than the high-ports.. on the heads mentioned above? there is absolutely NOTHING you can do with just a grinder alone, and I've met many pro's who have tried, to completely overcome the stock port location shortcomings on these heads. Because of that, the exhaust ports shortside radius will always be squashed. Overly large valves only make it worse since you can't fix the radius in the process. Increasing overlap and adding extra lift on the exhaust is all that you can really do to a factory style Ford head. PS. Those who really know various mfgr cylinder head shortcomings will tell you this. On a Chevy head.. you can almost always rob some exhaust flow to add to the intake and make more power. But you'll rarely do that on a Ford head due to the ports height and/or floor architecture. Because of that very fact.. a 1.50 valved Chevy port will flow more air than a 1.60 valved Ford head. And to go even further with that comparison.. a 1.65 valved Chevy port can even easily be made to flow more air than the Fords intake port regardless of the valve size used in a stock type valve arrangement. After all the smoke settles.. a general rule is that Ford's often need split patterns/overlap to compensate for that poor flow characteristic.. while Chev's actually go the opposite direction towards reverse splits and lower ratio rockers on the exhausts to ward off over scavenging/intake charge contamination. To remedy this.. aftermarket mfgrs high end products now uses Ford style intake ports on Chevy's.. and Chevy exhaust port config's on Ford's. All I can say is.. better late than never. lol
WOW. I put a trick flow stage 1 with 1.7 RR's and it screams! Really pulls to 6500 when you take it there! Should run out before that but seems really strong! I used it as it is a common cam for mustangs.
yeah.. I hear ya.. and remember that compression can do that to an engines torque curve. It starts early.. and ends late. Last custom cam I had in my little 302 w/ported hi-po heads and 1.7's was only .500 lift/224 @.050 and yet it puuled right up to 7,100. Some combo's just work better than others.
Try this, put in 3 requests to 3 cam companies and see how many give you a different grind for the same request. I'm betting you'll get a different grind in talking to different "tech guys" at the same company. Motors you're advocating (peaky HP/torque bands) are fun for about 10 minutes on the street. Been there-done that. Broad power banded motors are far and away better choices for a street driven car or truck. There's nothing "left on the table" in that. That carbed Explorer motor was one I ran in an 89 Ranger, backed by a toploader 4 speed, and a 3.73 rear shod with 275/60 rubber. It was extremely fun to drive, everywhere, anytime. I never got tired of driving it. I only sold it cause the truck was getting "long in the tooth", the motor never gave up the ghost, (and it was built from spare parts at that) it's still going strong for the guy who bought it from me.
