383 240z Posted February 1, 2003 Share Posted February 1, 2003 How much does rear gears affect your cam choice? I'm asking because I pulled a motor from a truck with a 4 speed and 2 series gears I put it in a 3200 lb car with a 700r4 and 4:10 gears and it is a DOG!!! I'm still studing about cams before I pull this one to optimize the motor for my application. Keith Quote Link to comment Share on other sites More sharing options...
Mudge Posted February 1, 2003 Share Posted February 1, 2003 It can affect you in a big way, especially with an automagic. If you expect to run a 244/244 cam on a 2.73 rear gear for instance, likely thats a bad idea for driveability. Quote Link to comment Share on other sites More sharing options...
383 240z Posted February 2, 2003 Author Share Posted February 2, 2003 I'm looking for a converter that will match the new cam but my converter builder wants the cam specs. The cam grinder wants the converter specs so I'mm really in a catch 22 here. I would just pick a decent middle of the road cam and stab it in but you have to pull the motor to do this. And it is a bit chilly outside yet and my shop does not have heat!! Keith Quote Link to comment Share on other sites More sharing options...
Mudge Posted February 2, 2003 Share Posted February 2, 2003 Well, I'm not an automatic guy, but it seems easier overall if this is a street car, to stick with a moderate cam and converter setup. If you want any kind of MPG out of it that is to say. If its a full on race car, then a 5000 converter and a huge cam may be fine for you. But, since I am not an automatic guy all I could ever possibly recommend is to stick with something not too wild, since going outside of the margin is not something I am schooled in. Like a 220/230 would be pretty liveable, a 230/240 or thereabouts is when things start to get out of the street range, depending on gears and converter setup... Quote Link to comment Share on other sites More sharing options...
383 240z Posted February 2, 2003 Author Share Posted February 2, 2003 I want to drive this on the street daily so MPG and idle are important but I dont want to get shown up by 5.0 mustngs and a stock C4 type of cars The weight in my previous post was abit heavy the cars weighs about 2800 lbs Keith Quote Link to comment Share on other sites More sharing options...
Mudge Posted February 2, 2003 Share Posted February 2, 2003 Wow, if the car is a dog with 4.10s is there a big cam in there now? Putting the setup in a much lighter car will of course help, but you dont have 4.11s in the Z I assume? This is going into a Z or is this Domestic still? Quote Link to comment Share on other sites More sharing options...
383 240z Posted February 2, 2003 Author Share Posted February 2, 2003 No it is in my 87 RX-7 I posted my question on the V-8 rx7 board but I trust the grey matter on this site much more. Keith Quote Link to comment Share on other sites More sharing options...
jbeech Posted February 2, 2003 Share Posted February 2, 2003 I'm moderately experienced with SBC in Z-cars and would hence, suggest you need to provide a bit more info anybody can advise you. For example, there is a question in my mind of whether you actually have 4.10 gears in the rear presently, or somethng else. When selecting a cam for a SBC, how you plan to drive is paramount. You have expressed a desire to maintain fuel economy while also not wanting to be spanked by 5.0 Mustangs, and C4s. While these are not mutually exclusive parameters, they are somewhat at odds with each other. Frankly, with 4.10 rear gear set, you shouldn't be embarassed by them now, which is why I wonder about the rear ratio you state - are you certain of the gears? It's easy to figure out by placing a chalk mark on one of the tires and on the drive shaft and then count revolutions of the driveshaft to make one complete revolution of the tire - it should be close to 4:1 for that 4.10:1 gear set you putatively have. It also helps to know more about your engine, i.e. intake/exhaust setup, does it have a single four or dual 4-barrels carbs - or FI, is the intake manifold a single or dual-plane, is the engine equipped with headers? Also, are your heads equipped with 1.94 or 2.02 intake valves? Don't forget to tell us what compression ratio the engine has, and also the cc of the combustion chambers. While you are at it, it would help to know if the engine is equipped with stock 1.5:1 rockers or long 1.6:1 rockers. Are they roller tip or stock? Also, do you want a mechanical lifters, hydraulic lifters, or even a roller cam? Presuming the car will always have an automatic tranny, there are indeed 4.10 gears in the rear, you expect this to be a daily driver, the engine is equipped with a dual-plane single 4-barrel (and is not computer controlled), the complression ratio is around 9:1, the engine is equipped with stock rockers, has headrers, and you desire a hydraulic non-roller cam with a stock torque converter . . . I would recommend something like a Crane Energizer 272H. This camshaft has specs of 272 degrees of advance duration, gross lift .454", and is well suited for an RPM range of 1800-5400. It'll have a decent idle, and provide good low to mid-range torque Quote Link to comment Share on other sites More sharing options...
383 240z Posted February 2, 2003 Author Share Posted February 2, 2003 I'm POSITIVE that I have 4:10's this is not my z I'm having problems with my other hybrid. The car is an 1987 rx7 It will be an automatic until the tech sector rebounds to 2000 standards or they give T-56's away in crackerjacks. The intake now is a stock gm cast iron. I bought an Edelbrock Performer RPM for this motor. I have a set of GM 462 heads to go on. But it has GM 642 on it now. I'm not sure what the compression is.(it is still a bit to cold outside to pull a head to check) I had to fight the urge to tear into this motor as I needed to get this running on a VERY low budget. I'm using a 750 vac holley. I have a set of 1.6:1 roller rockers here and the set of 1.5:1 stockers that are on the motor now. As for the new cam I don't mind a solid lifer cam and for the converter that is not a real big deal to me as My company owns a converter build shop!! Keith Quote Link to comment Share on other sites More sharing options...
jbeech Posted February 3, 2003 Share Posted February 3, 2003 What did the motor come out of? That'll likely provide an answer to details of the engine without pulling a head . . . I suspect it's very cold in PA so no need for that nonsense! As for not minding a mechanical lifter cam, I suspect you will about the third time you adjust the lifters. I think the 272H will be a nice cam with that Performer intake and 1.6 rockers. A cam with more duration might get a bit miserable on the street. Working at a converter place might prove handy. Personally, I'm more the windy road type Z-cars so I shouldn't comment on your choices of transmissions - I just picked up a T-56 for mine and the automatic is coming out (gee, I guess I just did comment - sorry). Good luck, Quote Link to comment Share on other sites More sharing options...
383 240z Posted February 4, 2003 Author Share Posted February 4, 2003 I'm planning on putting a T-56 in the Z. But this is my driver. I though about runnong the specs on the donar truck but the guy I bought it from (good friend) Had rebuilt it but cant remember what pistons are in it. He is fairly certain that they are flat tops with 4 valve releifs. I'll most likely drive the car home sometime this week and pop a head when I get a bit of free time. Unless I can find an endoscope. I think I know sombody who has one. I wont know the exact CR but it will let me know if they are flat tops or dished. Keith Quote Link to comment Share on other sites More sharing options...
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