Now I know there have been tones of threads on cams here, but I wanted to see what people thought of the two Isky cams, or if there is a better grind for my little AV8. I'm rebuilding a motor that I've spent a fair amount of time opening up the exhaust ports, and cleaning up the intake runners, so it should be able to breath fairly well. I'm just not too sure what cam to use. It's an 8BA with a 4" Merc Crank. What has everyone found as a cam that I could drive all day long, sounds good, and won't poke any holes in my new Navarro Heads.
400 Jr sounds better, but Max 1 will give better overall perfomance on the street (i.e., more low and mid-range).
I have a max 1 in my T modified runs real smooth through the smittys but when ya uncap the headers you can tell theres a little cam in it. Speedway catalog says the 400 should only be used for racing but I dont think its that wild of a cam.
I put the max 1 in my dads 3 5/16 x 4 8ba and it runs real good, but it sounds like a stocker (no lopepadelope) Im putting the 400 in mine.
reds headers do an isky cam, spring package & hollow lifter package, not sure how the price compares to buying them individually. http://reds-headers.net/index.php?main_page=index&cPath=4&sort=20a&page=9
Given the very light valve train of the flathead - you really should almost NEVER need dual springs . . . even on a big .450 lift cam. Very few people really rev the heck out of their flatheads these days --- so you don't need to worry about 7,000 RPM and trying to set 1/4 mile records. I've used the single Isky springs with a nasty .450 custom grind cam (flat tappet), with 6 lbs of boost . . . ran through the traps at 6800 rpm without floating the valves. I used 90 lbs on the seat. I recommend that you use the hollow adjustable lifters - not the solid ones (that I think Isky still sells - they're slugs). As far as spring pressure, you only need about 70 - 80 lbs on the seat. Heck, some guys go as light as 60 - 65 lbs on the seat. I like the Isky single valve springs - they work fine . . . even with big cams. Keeping the lighter spring pressure also reduces the wear on the cam . . . which is a good thing. If you want a cam that runs extremely well on the street and has a good lumpy idle, consider the Potvin 3/8 . . . it sounds great and runs like a raped ape.
The last flathead I owned and built was a 3&3/8 X 4", dual '48s, Offy heads, ported and relieved, 400Jr cam. Had it in a '32 3 window, channeled and fenderless. Ran 11/39 (3.54:1) rear gear and a 28t cluster set in a '39 trans. This was in the late 50s, early 60s. Drove it all over Hell on the street, even downtown Atlanta, never regretted my cam choice. Why buy a cam so mild that all you can say is- " I hear a little lope", especially if it's streetable, and has an OK low end with a hotter cam? Dave
I'm really leaning to the 400 Jr. with the Isky Springs. Someone was saying that the Potvin 3/8 had poor top end performance, and didn't sound as good as the 400JR. Man, I need to hear them.
Mine's almost done. When I get the water pumps and flywheel figured out you can come over and hear mine...
I've got the Max 1 in the tired old standard bore/stroke 8BA in my 29 AV8. The engine was not rebuilt; I relapped the valves and have 100-120 psi compression across all the cylinders. 8:1 Edelbrock heads redomed by Ol Ron, a set of hollow adjustables with Red's Lincoln valve springs & inside the frame headers running through a pair of Smittys, crab distributor, standard Mellings oil pump, aluminum timing gear, gravity fed from the stock Model A tank with Edelbrock Super intake and a pair of 94's. Running a 2.8:1 1st/ 1.6:1 2nd ratio 39 3-speed and the stock Model A 3.78:1 banjo with 750's in the back. You can't really hear the lope when it's running through the out the back Smittys but it sounds great when the lakepipes are uncorked. The engine has plenty of low rpm torque and pulls strong at 70 mph on the interstate. I've had my share of over-cammed engines. If I did it all again, I'd do it all again The sidepipes are open in the YouTube Video: <object width="425" height="350"> <param name="movie" value="http://www.youtube.com/v/RVMkOoUzvwc"> </param> <embed src="http://www.youtube.com/v/RVMkOoUzvwc" type="application/x-shockwave-flash" width="425" height="350"> </embed> </object>
i have a potvin in my merc and it pulls hard and they sound wicked at an idle here is a link to one http://s201.photobucket.com/albums/aa2/buflochp/?action=view¤t=Potvin38-1.flv
I'm running a Potvin Super 3/4 in my .030 over Flathead with a stock 3 3/4 stroke. It has a similar lift and duration as the 400 jr., it works well, but it loses some of the low end torque that a smaller cam will give you, it doesn't really start to come alive until 3k rpm. So think about how you will be driving the car and where you want it to perform well at, don't buy a cam just based of of it's sound. T
Good information to point out! Putting a big cam in a small cubed "stocker" type motor may sound good, but it sure won't help your low-end torque. Consider your application, the weight of the car, the rear end ratio, tire size, etc.. ---> it all comes into play. If your engine is mostly a stock engine with a slight overbore and dual carbs, you'll be much better off with a MAX 1 than an Isky 400. The bigger cams are much better suited to larger engines (270+ cubes), with port work, special ignitions and lighter cars.
My engine has a 4" crank, bored to 3 5/16 +.030 and has had port work done on the exhaust and intakes. The car is an AV8, pretty light...I'm ever so slightly leaning to the 400 JR.
It is best to think of the 404-A as a true race cam. It takes special radius lifters - that must be "keyed" into the lifter bores (so they don't turn). Isky hasn't made the radius lifters in many years -- trying to find a used set is near impossible. The 'jig' to drill the lifter bores for the key-wires is also extremely hard to find. Also, the 404-A is pretty hard on the valve train in general - as it has very fast valve acceleration ramps and hammers the valve train pretty hard. For a full-on race motor . . . one of the best cams ever made. For a street car . . . probably not worth the trouble and expense to run it.
I was reading "How to build a traditional Ford hot rod" by Vern Tardell and Mike Bishop last night...detailed buildup of a traditional AV8 using 95% old Ford parts. It's a good read if you don't have it. Anyway, in the engine section, they compare these two cams in detail and end up using the 400Jr. for some pretty good reasons. I can post more specifics when I get home from work if you're interested...
If you need to find a little low end with a 400,advance the timing events 2-4 degreese.400 has a late intake closing either run alot of static or advance the events.Run a low static and put it straight up you will need a ton of ignition lead to get it to perform with any manners on the street.
I spoke with Mike at H&H and talked to him about the Navarro heads, my intake, etc. and he set me up with a nice idea for a Winfield grind. I'm going with that. Thanks for all the help.
Great cam . . . won't sound as radical as some of the others (400 JR, Potvin 3/8), but will have a good low-end and will run really well.
Question, I have an old race motor sitting on a stand. 3 7/16 x 4 1/4 stroke ,Evans heads,Evans 3 deuce intake, and yes, a 404-A Isky radius lifter cam. This is a big engine with a big cam- Ported,relieved,etc,etc,etc. Can this engine be run on the street? long distance 100 mile freeway drives?
I guess the answer kind of depends what you expect from it! Things to ponder: 1) With a 3 7/16 bore, the cylinder walls are pretty thin -- which will tend to put more heat into the cooling system. So if you're thinking about this, make sure everything in the cooling system is top notch -- updated water pumps, big radiator, good fan, maybe a shroud, etc.. You might think about 'Skips' water pumps -- he makes some really good and updated pumps. 2) 404-A: This is a pretty radical cam . . . at least for back in the day. With the large cubes you're running, it will be tamed down a bit . . . so it is probably "steetable" . . . as long as you don't have a heavy car and you don't expect it to have a big low-end. Cubes always help . . . so it might not be too bad. Due to the fact that the lifters don't rotate, you tend to get some pretty heavy side-wear on the lifters themselves -- as well as the bottoms as the cam always hits the same place. If I was going to put it on the street, I'd definitely take a very close look at the lifters and guide wires -- as you can't afford to have the slot-guide system fail . . . which will break a lifter, usually then it will break the cam, which falls into the rods/crank . . . then grenade your motor and pick it up in a wheel barrow. 3) Bearing Clearances?: In a typical race motor like this, there will be increased main/rod clearances -- probably .001 per inch of journal diameter. Make sure you have a good oil pump, are running the best oil you can and keep an eye on things. If you haven't checked the bearings - make sure you do before you expect it to live on the street. 4) Piston Rock: Witih that long of a stroke, the pistons are really short - which means they'll tend to rock a bit more and you'll probably burn a bit more oil than a normal flathead street motor. Pay close attention to your oil levels. Also, make sure you have the best ignition you can afford - will really help this old beast. 4) What type of car are you thinking about putting it in? What are you running for a flywheel (weight), transmission and rear? I think it would be fun to drive on some trips -- as long as it cools well and you don't expect to put 20,000 miles on it before you tear it down. With frequent inspections of the valve train - you will be able to keep an eye on the valve train and make sure things aren't wearing poorly. Heck, if the cam and lifters wear out, just swap in something else! Keep me posted . . . I like engines like this! Dale
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