Basically, I am trying to build the most powerful Maverick I can without going crazy (maybe a little crazy) that I can still drive on the street sometimes. I want to build this so it is powerful as hell but I can still take it to run errands ever so often to show it off and drive it to the drag strip (about an hour drive) or car shows. I am trying to figure out a head and cam combo and here is what I would like to run... Plans for rest of engine: 302 bored and stroked to 347 dual plane, air gap intake fuel injected MSD ignition Long tube headers 1.6 rocker arms (maybe 1.7) Here is the cam I want (pretty aggressive) Mechanical Roller Ford 289-351W (351W Firing Order) Application: Max Torque RPM Range: 2400-6500 Duration @ .050": 246/254 Adv. Duration: 286/298 Lift w/1.6 Rockers: .616/.632 Lobe Sep. Angle: 108 Valve Lash: .024/.024 10:1+ Lopey idle, Strong mid-range Here are the heads I want Cylinder Head Material Aluminum Combustion Chamber Volume (cc) 58 CNC-Machined Combustion Chamber Yes Intake Runner Volume (cc) 225cc Exhaust Runner Volume (cc) 95cc CNC-Machined Intake Runner Yes CNC-Machined Exhaust Runner Yes Intake Port Location Standard Exhaust Port Shape Square Exhaust Port Location Raised Intake Valve Diameter (in) 2.080 in. Exhaust Valve Diameter (in) 1.600 in. Maximum Valve Lift (in) 0.700 in. With the cam... would that be too aggressive for street use? With the heads... they seem fantastic. I like the raised exhaust ports and I think the size of the runners will be great. The problem with them is the combustion chamber. With a 58cc my engine will be at an 11.0:1 but the heads are aluminum, is that still too much for premium fuel? I've heard of people running 10.0:1 on cast so could I get away with it without retarding my timing too much? Thanks for the help guys this is my first muscle car build and I would like to look over everything
If you wanna get the best of both world I would go turbo, you can have it behave mildly off the boost and retain the gas milage. Then make more HP than you would ever with the stroker once the boost comes in. And the price would probably end up being the same as an all out NA build. Check out the builds on this forum: http://www.theturboforums.com/smf/index.php?board=31.0 A lot of them are budget builds, since they use a cheap rebuilt 5.0 with stock parts. And run a turbo capable of running tens in full street trim. The precision turbos are pretty cheap if you get the bare bones entry level ones. And they are phenomenal compared to the old technology turbos.
i kinda agree with alex. defiantly go with boost. now what type of boost depends specifically on your goals or intended use. for what you described a turbo would be good. now its not as simple as putting on a turbo. you can build a turbo motor in lots of different ways. if you build a turbo motor to give you max power to drag race with it will be horrible on the street. it will have no power curve. it will have basically two settings on and off. i would suggest not going for the most power but something mid range. a 9 to 1 compression ratio with mid sized turbo. it will drive like a beast on the street and still run really hard. it should have around 600 hp easily. now consider the stock ford 5.0 and 302 blocks are known to split in half at the 500-550 hp level. if you don't want to spend the money then plan on making 500 hp. now you could use a smaller turbo. this will get your faster spool up times and should get you some good gas mileage.
you will want the lightest pistons, rods and crank that you can get. your intake selection is most likely too small for the heads and cam you have selected. also you should have custom big tube headers made for the motor. you should be able to make the 500 hp that will max out a stock block but its going to have rev really high in the rpms. that will require a really loose converter with a really high stall speed that wont be street friendly.
First of all the choice of a dual plane and fuel injection isn't what's normally done. . The dual plane isn't needed with(port injection I assume) fuel injection. And the cam is pretty big and with a narrow lobe separation for fuel injection, it's going to play hell trying to get it to idle anywhere below 1500 rpms. If you want the best of both worlds, go with a cam that's got a wide (efi grind) lobe separation, high lift (mid to upper .500's) and a lower comp ratio (this will be necessary with the wider LSA cam). My 331 has a pretty wicked lope at idle (in gear with the C-4) but has excellant street manners, just about all I do is tool around town with it. And it runs on 91 (conventional) pump premium. I don't know how many times I get positive comments sitting at a redlite, after they hear the motor idling. The key to all this is a hot ignition (Ford Duraspark) a smallish carb (the primary carb on my 3x2 is a 250 cfm rated 2 bbl) and a wide LSA cam (the Z303's LSA is 112*) And the high rise dual plane ties it all together. My static comp ratio is 10.4 to 1. The power comes on at 1500 and pulls to 6500.
So with EFI it needs to have a wider LSA? and if you don't mind me asking, why does a wider LSA require lower compression? This is the other cam I was looking at in case that one was too agressive. This will definitely be the cam I'm getting Ford 260-351W (351W Firing Order) NOTE: 221-302 applications must change ignition firing order to 1-3-7-2-6-5-4-8 Duration @ .050": 224/232 Adv. Duration: 280/288 Lift: .534/.547 Lobe Sep.: 112 2200-6200, Fair Idle, Mild Street Performance, Crisp Throttle and with 1.7's lift would be about .567/.581 if I needed to flow more air
The wider LSA keeps the intake charge reversion to a minimum at lower rpms. With almost all cam grinds, there's a certain amount of "overlap" ground into the profile. What "Overlap" means, is there's a period of time when both the intake and exhaust valves are open at the same time when the piston is traveling up the bore on the exhaust stroke. This allows some exhaust to get pushed into the intake tract before the exhuast valve fully closes and the piston reverses direction at TDC. The reasooning behind having the two valves open was to allow some scavenging of the exhaust by using the velocity of the intake charge to help push all the exhaust gases out while the two are open at or near TDC. But at idle (and to some extent the lower rpms) some of the exhaust gas gets pushed into the intake tract because the velocity of the mixture in the intake is too slow to prevent this from happening. EFI cams have a wider LSA (Lobe Separation angle) than those intended for carb use, this shortens the amount of overlap in cams with the same lift and duration, but a bigger cam with a wide LSA can have a longer overlap than a shorter LSA cam if the lift and duration is less. I've found that carbs like wider LSA cams on the street because they spend more time in the lower rpms. This increases the amount of the vacuum signal as well, making the carb circuits more responsive. I don't know how much experience you have with carbs, but vacuum in the intake is what draws the fuel from the carb into the intake charge. With EFI, you can run a bigger intake (plenum volume) because the fuel is injected into the intake stream at the ports (unless you go with a throttle body injection system at which point a dual plane may work better as it's basically a carb/injection combination) The cam you list here is very close to the specs of the Z303 cam I'm running, except the lift is higher with my choice of running 1.7 rockers. Also keep in mind that a solid cam will require periodic valve adjustments that a hydraulic cam doesn't. The solid grind is only going to help you in the extreme upper rpms (above 7000 rpms)vs a hyd cam. A hydraulic roller is good to 7000-7500 with good lifters. No one in their right mind will continually push a 347 into these ranges in a street driven car. The only time you'll see that is on the track
No offence I really appreciate all the help and you going through that with me but to save you some typing time I am pretty engine savvy and I understand most of how an engine works. Mostly I need help with understanding how an engine runs with different specs due to lack of experience. So you said carbs need a wider LSA so the vacuum pulls the fuel in, so if I went with fuel injection (still deciding throttle body or forking up the extra cash for direct port) could I use the narrower 108* LSA of the first cam? I don't mind adjusting valve lash (I won't have shock towers in the way anyways) how far do most people rev built 347's?
No, I said I found that carbs also work better in street applications and driving with a wide LSA cam made for EFI applications. The computer in an EFI setup will have difficulty dealing with the reversion pulses in the intake tract which is a result of the short LSA cam. You ever been to a track where someone's got a REALLY hot EFI dragster ? You'll hear what I'm talking about. It'll sit there and the rpms will go up and down, thrumming in pulses, that's due to the computer trying to deal with the reversion pulses in the intake. How far do they rev em ?(a 347) That's going to be a question you'll have to ask someone who has one. The rev limit I imposed on my 331 is 7000, but I shift at 6500. This motor is now 7 years old. Will it rev higher ? Yea, probably, but I have no desire to subject it to that kind of stress as it's all done pulling at 6500.
When a cam is designed to be used from 2400 (or 2200) rpm to 6000+ it should tell you that it will not work for the street unless you are going to running the engine no lower than 2400 rpm. Around town that is nearly impossible. Most street engines spend most of their time between 800 and 1200 rpm unless they are being driven on the freeway more hours than on the street; even then you have to drive it to the freeway. On the street (at legal speeds) even with 4.11:1 rear gears a car would rarely see more than 4000 rpm so it would make more sense to get higher average torque and HP in the idle to 4000 rpm range than from 2400 to 6500 rpm. You are describing a racing engine that you think will be fun to drive on the street. I have done that and it was not fun. It was a constant nightmare of retuning just to keep it running and even at freeway speeds it was well below the torque curve. If you want the best of both worlds build a low compression engine and supercharge it to get the performance level you want.
The only problem with going by the advertised rpm range of a cam here is, he's looking at cams listed for a 302 while building a 347. In this instance, the rpm range changes, the extra cubes moves the rpm range downward, but not far enough down the scale to make it streetable, if you're talking about the first cam he chose. The second cam will work fine on the street in a 347, it's not too much different from the Z303 I'm running.
Ok thanks for the help I misread your post. So EFI has to use a wider LSA cam. So I am pretty sure I will be using the second cam I posted with 1.7 ratio rockers and it has a 112* LSA, which I was taught needs to be that wide for EFI, and a power band of 2200-6200 along with a different set of heads I found, these http://www.summitracing.com/parts/DRT-13072142/ They have a 62cc combustion chamber which puts me at about a 10.5:1 compression, they don't have the raised exhaust ports but they should still flow like crazy. How does that sound?
fuel injection does not need the wide lobe separation. now factory systems need but aftermarket progamable ones do not need the wide lobe separation.
More than likely, the power band will start sooner than what's advertised as it's likely based on a 302 cubic inch motor.
