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Old 11-01-2008, 12:03 PM
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recommanded cam for 350

hey guys, im rebuilding the 350 in my jeep once again and wanted see what yall would think about this set up. its a 1980-1985 crate Gen 1, 350, 2 bolt main, COMPLETELY stock except for some cheap-o-depot valve covers and edelbrock carb.the engine only has about 500 miles on it so i know it wont need to be bored. I think im going to go to aluminum heads, (not sure what brand yet) about 64 cc combustion, 180-195 intake, roller rockers, with edelbrock airgap intake, and stick with my 650 carb. Now the cam is killing me, a buddy of mine was going to rebuild his old truck and decided to sell instead so i have a brand new lunati hyd. flat tappet cam with lifters ready to go. the specs are 235/235 duration at .050 lift (285/285 advertised) and .507/.507 lift. with 108 lobe separation. The goal here is some pretty significant numbers over the underpowered crate, and very road friendly( this jeep never sees the offroad except the grass in the front yard). Im keepin the pistons, rods, and crank all stock so im not asking for a race motor, jus some good power. would this cam be right for this set up? i dont really mind a some what choppy idle as long as its not horrific. just let me know what yall think... Thanks in advance

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Old 11-01-2008, 12:13 PM
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for a street driven jeep you want low end torque. Jeeps can't have enough torque. I would recomend going to a much smaller cam and running some stock vortec's. AFR 195's are great heads and are the hot ticket for a hot street machine, but they are too much for what you need. I would recomend a cam with about 210/215 duration @.050" and as much lift as you can find at those durations, along with 1.6 roller rockers. Instead of looking at HP numbers for your build look at torque numbers- the higher the numbers and the lower they are the better. If you want good milage run a wide LSA on your cam- around 114 or more. If you want max midrange torque you can go as narrow as 106 and still be streetable witht the smaller durations I gave you.

Also, the AirGap is a great high hp street manifold, but the performer will give you better street manners, low end torque, and costs roughly half. Just swapping on the parts I listed will run you about $1300 and will be enough power to tow the biggest boat you can fit on your jeep- in other words will have more than adequate power.

After this post I don't expect you'll se a lot more on your Jeep- I'm betting almost everyone on here is going to tell you the same thing. Some may recomend going with a roller cam, but its not needed on your setup.
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Old 11-01-2008, 12:44 PM
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hey man great info. but how do you think it would run with the cam i listed in the first post. at idle? just curious. im just always terrified of building an engine with a horrible idle.. thanks.
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Old 11-01-2008, 02:02 PM
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It would have a choppy, rough idle. But I agree with the following post overall. Vortec heads and a performer vortec intake would serve you nicely. If it were me I would use a Quadrajet carb instead of the edelbrock. If you want a cam that idles with a lope but doesn`t kill off low end torque, then you want the comp cams magnum 268 which you can view here to see the specs.
http://store.summitracing.com/partde...2&autoview=sku
I also agree Jeeps need lots of low end torque, most I`ve seen have really high gears so this compounds the problem, this is why I recommend a Quadrajet, it`s small primarys make for excellant low end torque and throttle response. Since your doing a build I have a set of never used speed pro Hyper 2 valve relief flat top coated skirt pistons for sale at a very good price. Let me know if your interested.
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Old 11-01-2008, 08:35 PM
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hey double, thanks for the info and specific cam. I am infact interested in the pistons, i sent you a private message but dont know if you check that or not so i put it on here to, please contact me back. but with the 350, would it be wise to just purchase a full rotating assembly with heads, cam, pistons etc... like the kits from summit. I would love to do a roller cam, but have never retro fitted one before, and looks like it might be a little difficult, please let me know what you think, or how i could do this... thanks
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Old 11-01-2008, 10:18 PM
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Suggestion

If you can swing a new set of flat top pistons, you are going to appreciate the torque it will give you. In conjunction with a set of Vortec heads, you are going to give yourself a pat on the back, as well as feel the difference they make working with the other parts you have.
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Old 11-01-2008, 11:02 PM
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If you want to build a powerfull jeep motor around your 350 crate motor ( with stock dished pistons) and that Lunati cam, you want a 58cc to 60cc cylinder head and a thin .015" head gasket to get the cr up to where it needs to be. You can flat mill a 64cc heads to achieve 58-60cc. Install the camshaft advanced on a 102 to 104 intake C/L.
Use a performer RPM manifold and headers.
You will need a high stall torque converter (10" 3500stall for a th 350 trans).
A stock torque converter will not work.
The distributor advance curve will need to be modified for that camshaft
24deg inital base timing at idle ,, 34 to 36 total advance + 12 to 15deg of vacuum advance.
Your carb will need the power piston springs swapped for light tension springs.
Once these changes are make the motor will idle and run just fine (rough and steady)
A L-31 vortec head modified/upgraded for high valve lift and milled to 58-60cc would be a great choice.
The jeep will need a 3.55 to 4.11 gear ratio. More if you are using very tall tires.
Cam specs
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Old 11-02-2008, 08:41 AM
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F-bird'88, while that would be a fun engine for some of us o drive it wouldnt be very street friendly at all in a daily driver Jeep.

As far as the cam that you have goes... Its a nice cam, but not nice for what you're doing. The 268 cam is not a bad all around cam for most street machinces, but being yours is a Jeep I would go down even further to a 262. You can go down even further to a 256 if you wish but you will see diminishing effects. 262 seems to be a good cam for hopped up trucks and would suit your jeep well. It would also be better if you're looking to keep your stock pistons. If you keep the stock dish with a Vortec head milled to 60cc's and a thin head gasket your compression won't be too bad, in fact if you're looking to run 87 octane it would be just about right.

As far as gearing goes- that's a whole other story but if you're planning or running 31" tires or bigger I would recomend 4.10's at the minimum- I like passing power though- some would say you can get away with 3.23's as long as your cruising only.
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Old 11-02-2008, 09:54 AM
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Beg to differ

Quote:
Originally Posted by ap72
F-bird'88, while that would be a fun engine for some of us o drive it wouldnt be very street friendly at all in a daily driver Jeep.

As far as the cam that you have goes... Its a nice cam, but not nice for what you're doing. The 268 cam is not a bad all around cam for most street machinces, but being yours is a Jeep I would go down even further to a 262. You can go down even further to a 256 if you wish but you will see diminishing effects. 262 seems to be a good cam for hopped up trucks and would suit your jeep well. It would also be better if you're looking to keep your stock pistons. If you keep the stock dish with a Vortec head milled to 60cc's and a thin head gasket your compression won't be too bad, in fact if you're looking to run 87 octane it would be just about right.

As far as gearing goes- that's a whole other story but if you're planning or running 31" tires or bigger I would recomend 4.10's at the minimum- I like passing power though- some would say you can get away with 3.23's as long as your cruising only.
The 268 would probably work out okay for his needs, IF he couples it with F-Bird'88's suggestions, especially the torque converter & rear end gear changes.

I built a daily driver with one of F-Bird's suggested builds, and I am thrilled silly! Bottom end torque is NP with my 4300lb truck & I even have a lift gate hung off the back bed... sort of like a combo wheelie bar & traction device

A jeep has less weight to haul around and with the changes prescribes, he will have enough torque for a daily driver, especially if he is starting out with a basic low compression stocker & big wheels.

Last edited by DENCOUCH; 11-02-2008 at 09:59 AM.
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Old 11-02-2008, 10:48 AM
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hey guys, let me put some facts out there, its a 84 cj7, complete fiberglass body with 35's and 4:10's already, runnin a TH350 tranz, and NP205 transfer, so the only weight the motor has to push around is basicly itself, and the tires. Im just looking for a bad street motor to turn heads, and lay down some rubber of my 35's. i decided to cancel one of my other projects and just focus on this one, (for financial purposes) so im going to go ahead and change out the pistons to flats with 2 valve relief, runnin 65cc aluminum heads most likely, and since im doing all that i will probably change out the crank and rods too, but what type of cam will i have to be lookin at now?
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Old 11-02-2008, 11:11 AM
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With aftermarket heads I would limit the cam to maximum 224* single pattern with a 107* LSA timed at 103*. That will put your power peaks at 4700 and 6100.
You might consider backing down to a 218 single pattern cam.

Overall compression is a major consideration. If you are using the stock crate pistons with their poor squish/quench ring, you should limit yourself to 9.0 maximum, .045 squish distance, and with precision ignition timing curve.

Don't fall into the trap of overcamming duration and wide LSA and then sticking in a bunch of un-needed and harmful exhaust duration in an attempt to flatten the torque curve.
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Old 11-02-2008, 12:54 PM
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Quote:
Originally Posted by 350cruiser
hey guys, let me put some facts out there, its a 84 cj7, complete fiberglass body with 35's and 4:10's already, runnin a TH350 tranz, and NP205 transfer, so the only weight the motor has to push around is basicly itself, and the tires. Im just looking for a bad street motor to turn heads, and lay down some rubber of my 35's. i decided to cancel one of my other projects and just focus on this one, (for financial purposes) so im going to go ahead and change out the pistons to flats with 2 valve relief, runnin 65cc aluminum heads most likely, and since im doing all that i will probably change out the crank and rods too, but what type of cam will i have to be lookin at now?

If you're turning 35's with 4.10's then your really going to want a 262 cam or less. Truth be told you have no way of using the typical "bad *****" street machine engine, your gearing nad tires simply can't support it. You need to look at making maximum torque, not HP. When was the last time your tach ever read over 4,000 RPM? I doubt it has even 1% of the time you drove that viehicle, so don't try to build power in that area, build it where you use it.

If you really want a nice sounding idle get a 256 cam and have them grind it on a 106 LSA. You'll loose some fuel economy but you'll get a killer idle sound and still have plenty of torque to move your jeep.

F-bird is a pretty smart guy, but his engine theory doesn't change much according to application, he's not too wild, but not too conservative either. This type of rig is where you want to be on the conservative side because of your tires, drag, and gearing.
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