Originally Posted by Work Horse
Thanks for the response davis. I wouldn't question your motivation for using any parts in a motor. I have had nothing to do with 4V heads, only what I have read/been told. I was looking at a set on falcon coupes car the other month, it looked like my fist would fit in the inlet port!
2V heads get used for door stops there are that many about here, were as 4V heads are worth good money in any condition.
I can't believe you can not get better fuel in Arizona, the US is the biggest market in the world what's going on with that? Actually we use a different systems to measure octane. Our highest avaliable 98(Ron), is about 92.5((R+M)2) I think.
Thankyou for the offer of a motor, but I have enough trouble convincing the wife I need the parts I buy now. A box that size arriving from the States would definatly get her attention.
We can get better fuel at some stations, but by-and-large the average premo is 91. In the wintertime, they lube it up with a 10% dose of Ethanol. In the summertime, they douse it with 10% of MTBE (Methyl Tertiary Butyl Ether)...so who knows what we've really got!? The aim is to curb pollution from more cars here in Arizona than population of people in Australia...or very nearly at least. Being the world's biggest market for just about everything means that we're either over-regulated on most stuff, or that we're consuming so much of it that somebody has to do something about it so that we don't screw something else completely up. Of course, you Aussies know about being over-regulated...it is like your second skin...the EPA rules compared to the numbers of cars you have are outrageous. Still, one can appreciate the intention of keeping the environment in good shape.
California has some 30 million registered cars...or more than one for each person living there. You could fit about 30 Californias in Australia. My solution for smog is to send all of the Japanese cars to Australia <grin> Could you imagine how much room would be on the roads in the US if there were no rice burners!
I've had a bunch of 4V heads over the years. I've been getting rid of them to make space and because I really hardly ever use iron heads any more these days. This set is a set of 1970 heads, which are the small chambered versions that are nominally 64cc. I've got them over at my head guy's place where he is going to flow and cc them to see if there is anything else that we'll want to do to them before installing them. Again, I don't really build for maximum power. I try to make the entire combination "just fit right." Sometimes I'm fairly close and other times I'm not quite as near as I'd like to be. I think that I'm going to be okay with this set-up and that we should see a really nice, smooth power range from this engine that starts taking shape at 2500 and comes on really strong up to about 6000 RPM. That is really where a good street engine needs to perform. With a maximum redline of 6500, we'll be in business with a stout engine that will fit well into the fenders of a mostly street, sometimes strip ride...especially for a lightweight car with the right gearing and tire. I'm planning on using a 29.5" tall 10.5W tire. That is a fairly tall tire for a street car. I may end up going with a 3.89:1 rear gear. I haven't really started thinking too much about those numbers because it is a bit premature until I have a chassis.
I'm leaning toward the '65 Falcon because in Arizona any car '66 and earlier doesn't require emissions testing. '67 and later requires it. I love the body style/shape of the '67 Cougar, though. I figure that with 11:1 compression, I can run methanol for a few days and pass it off as an alternatively fueled vehicle. The law doesn't specify how much time it has to run the alternative fuel source, rather, it does if you want to try to collect on the tax credit. As long as I don't file for the tax credit, I can emissions test it on Ethanol or Methanol and run it day to day on gasoline.
About the funnest thing in the world is a 9000 RPM Cleveland running 15:1 on methanol! Shifting at 8800 with a 4.88:1 rear gear and a Richmond 5 or 6 speed is about as exciting as a small block-powered car gets. Can you say zero to six-sixty in five seconds?
As for the intake ports on the 4V heads, they are definitely large...too large by all accounts. Nobody has anything good to say about the exhausts, either. The funny thing about them, though, is no matter how "bad" they are, they still work relatively well with the right combination.
There are many schools of thought on the 4V heads. Intake velocity being a constant reminder of what a small port head can do, we can start talking about what can a BIG port head can do on a small engine. The trend is to open the valve early, leave it open a long time, let dynamic compression ratio (bleeding off early pumping action) work to your advantage with a large overlap camshaft and run like crap below 3500-3800 RPM because you don't care, you're launching at 4500-5500 anyway. To me, that is the definition of a race engine, not a streetable engine. Me, I look at the design from a different perspective. It isn't as powerful or glorious as the 9000+ RPM screamer, but it does consider some interesting design elements of the big port heads.
The first thing is to "under" cam it. Too many people get very upset when you don't run .600"+ lift with a 4V head. Think smaller. I'm at .550" on the intake and .570" on the exhaust. There are those guys who would say that this is way under-cammed. Lift has an interesting impact on flow, but more as a function of velocity than the total amount of lift. The problem that we all know about with the 4V heads is that velocity is a thorn in our sides. How do we achieve good velocity with "bad" heads? We trick the engine. Errr...probably more correctly, we trick our way of thinking about what an engine must do, does do and has to do to accomplish the job of making power.
Everyone here knows that a 2V head is a better street head. Why? Because just about any camshaft will work well with it, any gear ratio, and any car weight, tire size and carburetor and inlet and extractor size and transmission. Of course, there are definitely combinations that will work much better than others, but without a severe brain fart, it is fairly hard to make a 2V head fall completely on its face. This is true with just about any small port head...not that the 2V heads are small compared to other manufacturer's small block heads, just small compared to the MASSIVE 4V head.
So, how do we get good results from a 4V head? We know that velocity is going to be an issue. We know that "soggy bottom end" is the catch-phrase for describing a street 4V engine.
If we increase the static compression ratio, we're going to have a "harder hit" at the top of the cylinder. If we use a wider LSA camshaft, we're going to build more dynamic compression ratio and not bleed off much of the early pumping action. Also, we don't snap the valves open as much or for as long on the overlap while still maintaining enough duration to keep it healthy. What we do is basically move the RPM band of the engine into the sweet spot for the low-lift flow characteristics of the port. For a 4V head without any dramatic work done to it, this tends to be at around 3800 RPM to about 5500 RPM. Much less RPM and we're into the dreaded low-speed stall and much more RPM and the "bad" exhaust port comes into serious play. The good thing for us is that you don't need much at all to play in the 3800-5500 RPM range. Factory reconditioned parts will work well! The kicker is that true street engines are mostly 1200-4000 RPM engines and waiting until 3800 is not really an option. What we do to "combat" that "issue" is add static compression ratio to build more torque, wider lobe centers helps a lot too, and then we gear the thing like it is a pissed off rugby (Australian football) champ on steroids and way too much caffeine!
Combined with a lightweight car, the 4V headed 351C stands a chance at being both truly streetable (with appropriate fuel) and very responsive throughout its throttle range. It is a nice match for a close ratio 4-speed and a big rear gear like a 5.33:1. Not very highway-able though, which is why a modern-day 5 speed and less gear makes for a better street combination. Using a close ratio transmission and a big gear in a light car doesn't make very much sense unless you really want a true "city driving" hot rod or a corner-burner with an aerodynamic body to go with it.
I've often thought of building a custom car along the physical lines of a Volkswagen Karmann Ghia, but with a 351C. Viola...Pantera lite!
If you've ever riden around in a Pantera, you can attest to the premise that a 4V engine can be very streetable with the right application of parts and lightweight car. A 5-speed (ZF transaxle in Pantera's case) and a ring/pinion gear of about 4.11:1 and you're flying! If my memory serves me correctly, Pantera acheived its top end using an overdriven 5th gear (something like .83:1) rather than a lower first gear and higher ring/pinion. My answer is to run the Richmond 4+1 5-speed (that Richmond bought from Doug Nash Enterprises) that combines a lower first gear with a 1:1 5th gear to use a lower ratio ring and pinion for the same overall effect as the overdriven Pantera/ZF with a bigger R/P. If the car weight is kept to 3000# or less, the performance is astounding. The rev range is a sweet 2500-6500 with the right camshaft using flat tops and a good amount of compression. At 11:1, my engine has the right amount of compression for everything but the commonly available petrol. That is why 4V Cleveland heads "don't work" for really true street cars. People try to build them for pump gasoline and end up sacrificing the bottom end benefit that the much higher compression gives to the lower RPM range especially when combined with a wider LSA camshaft that increases the likelihood of predetonation when used with borderline petrol. I almost put a set of 12.5:1 pistons in this engine. However, with that kind of compression ratio, I really don't like to run factory rods. Part of my goal for this engine was to be as reasonably budget-minded as possible. It isn't as if I'm made of gold, but even if I was, I'd want to get the most bang for my bucks.
As I've said, in a big, heavy car, a 351C needs some help with a big cam and as much everything else as it can possibly get--including aftermarket alloy heads with dramatically improved ports and chambers. Of course a lighter car can do even better with a nice set of AFD or CHI alloys and matched, related parts. But, like I said, I already had a set of 4V heads sitting in a corner waiting for me to do something with them.
WH...I don't want or expect anybody to take my word for anything. I don't mind being challenged or having my theories put to the test. In return, I'll post the engine dyno details of this engine once I get to that point. It is nearly always possible to get a few more HP or some other aspect of performance out of an engine...but like I've said, I don't build for maximum power. I like to build for "best combination for the intended usage." Have I got all of the answers? Not on your life. Every engine I build is an experiment in one direction or another. So far, not a single one has done exactly what I intended for it. It is like the canvas of an artist. At some point, you have to paint some broad strokes, fill in some details and then, finally, pick some point at which it is done. Is it perfect? Never. Just a moment in time captured that was as right as it could be for the job at the time. Budget is always important. It is to everyone I know and I don't hang out with those kinds of people who burn money for no reason...not that I even know any of those kinds of people. If money was not an issue, every engine I'd have would probably cost a million dollars and still be some sort of compromise between what I wanted and what I got. This engine just costs a lot less! We'll soon see how closely it lives up to my expectations for it.
As for the wifey-poo, you need to plant a rather tall rose garden in the front of your house and then instruct your delivery drivers to drop packages behind the roses. Women will always be more keen on looking at the pretty roses than paying attention to the delivery truck and a nasty looking brown box! <grin>