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Discussion Starter · #1 ·
I have a comp roller cam for my 347 stroker...
It has adv dur = 290/290... 230/230 @.050 valve lift - .544/.544 Lobe sep=110.0
The factory recommends a 4.10 or lower gear with a 4 speed
I only have 3.55 with a wide ratio t10.... how will the car drive... I'm not too familiar with cams/cam specs and how that translates in to how a car will drive and perform. help please!!! thanks!
btw... aftermarket heads 185cc , rpm air gap intake, headers, 670cfm holly street avenger
 

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It will be pretty radical, and probably have a fairly poor idle. For reference, I'm running a 288°/288° (226°/226° @ .050) with .544/.544 lift in my 408. It idles pretty smooth at anything above 850 RPM. My cam doesn't have as much duration as the one your looking at, and I've got 61 more cubic inches taming it. I had 3.50 gears originally, and it worked fine with them. The current 3.89 gears, though, are a much better match for my TKO-600.

If you can stand the idle, it will probably scream. Make sure your valve springs can handle that lift, though, and that you have piston-to-valve clearance for that duration. That's a lot of cam. You may be looking for a bigger carb, though.
 

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Discussion Starter · #3 ·
can you explain "stand the idle"?
does that mean my idle will be so choppy that it might stall out or you mean it will idle high?
 

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Probably a dumb question, but here it goes..... What type of driving do you expect to do with your car? How often will you drive it?
 

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IMO, That's a pretty healthy cam. In fact, some might consider it a Monster, for street use. Is your car an Auto, or Manual Trans? I expect your car will have a Very lopey Idle, that will increase substantially. It should be quite snappy, while passing people on the freeways, and pretty stout at the stop lights. If you have an auto. you better look into a higher stall torque converter though, and consider beefing up your cooling system. Do you have sub frame connectors? :burnout: :burnout:

J.R.
 

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johnpro said:
You may be looking for a bigger carb, though.
Depending on your redline rpm and what the majority of the driving will be for this car, johnpro may be right. From my calculations, if this car is just going to be a street car you will be fine with your 670 if your redline will be between 6500-6900rpms. If you plan on taking this car to the strip a 750 would probably be a good compromise. Since you are going to run a dual plane intake you can get away with "overcarbing" the motor a little easier than you could with a single plane. If this car were only going to be a drag car then you would need a carb in the 800-880 range if redline was between 6500 and 7000 rpms. Hope this helps.

You will be fine with those gears on the street but it will hurt your track times. Another thing; do you have power brakes? I would think that vacuum would be an issue with that cam.
 

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squidz said:
I have a comp roller cam for my 347 stroker...
It has adv dur = 290/290... 230/230 @.050 valve lift - .544/.544 Lobe sep=110.0
The factory recommends a 4.10 or lower gear with a 4 speed
I only have 3.55.... how will the car drive... I'm not too familiar with cams/cam specs and how that translates in to how a car will drive and perform. help please!!! thanks!
btw... aftermarket heads 185cc , rpm air gap intake, headers, 670cfm holly street avenger
I'll buck the trend here; healthy cam, but is street drivable. You should be ok with the 3:55s, but deeper would be better. What kind of compression do you have? Here's a combo I ran in my Falcon Sprint Convert as my only car, daily driver years and years ago: 302, 351W heads, 9;1 compression (not ideal, needed more), SigErson HighFlow1H cam, [email protected]", .500" lift, Edelbrock F4B, Holley 600 vac, Hipo dual point(back in '82 I paid $20 for it!), dual exhaust, 4sp, 3:25 open. I had the idle set at 900rpm.

The car ran consistant 14.6s at the drag strip. It was my only car so I drove it every where - to work, on cross country vacations, etc.

You have 45 more cubes, and slightly deeper gearsgears, so it'll be fine. You'll have to goose the throttle and slip the clutch to get it going sometimes, but that is fun. Enjoy!
 

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Guess what? I have a 347 stroker with a solid roller cam. 230/230 with .590 lift (that is not a misprint) and 109 LSA. 750 carb.

The idle is only slightly lumpy at 750 rpm with 12 inches of vacuum. I have 3.89 gears and it will pull 5th gear (.62 OD) at 1500 rpm no problems. Plenty of low end and once it gets above 3500 rpm you better hang on. Revs freely to 6500 rpm. Launch it at 2000 and it hooks up and goes. Launch it at 3000 and it blows the tires off of it. IMO it is perfect. You have to realize that I live in an urban environment with lots of stoplights and I needed a cam with good low end manners. I can shift it at 2000 rpm if I want and it pulls just fine.

Now it USED to be 240/249 with 108 LSA. That was WAY, WAY, WAY too much cam on the street.
 

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I think you'll be fine. My cam specs at 230/236 Dur and .513/.526 lift with auto tranny, it idle at around 750RPMs. It does have a lopey idle but i like it. My gears are 389 and 2400 stall. If it was a daily driver that would be different, but for showing off on weekends and going to the strip once in awhile its fine. Plus you said you have a manual tranny so thats even better. I think you'll love that cam, I would, but i guess it all depends on the person.
 

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It should be fine..I used to run a camshaft with 244 [email protected] in my 302..At first I still had the stock 3:00:1 gears in the rear end..The car was still fine to drive but it would chug if you got too low in the rpm band in a higher gear..So driving around town I might have to stay in second gear instead of third to keep the rpms up a little..No big deal with a manual trans..Once I changed to a 4:11 rear it was great.
 

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Discussion Starter · #16 ·
ok now you guys got me not feeling too good about my 3.55 rear ratio.... Many people are telling me that with a 3.9 the car will break loose too easily because of all the torque and that the 3.55 will help the car hook up much easier...
is this true or is it bs and i should just go with a 3.9?

btw.... my compression should be around 10.0 - 10.2
 

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Discussion Starter · #17 ·
68RCodeConv said:
Guess what? I have a 347 stroker with a solid roller cam. 230/230 with .590 lift (that is not a misprint) and 109 LSA. 750 carb.

The idle is only slightly lumpy at 750 rpm with 12 inches of vacuum. I have 3.89 gears and it will pull 5th gear (.62 OD) at 1500 rpm no problems. Plenty of low end and once it gets above 3500 rpm you better hang on. Revs freely to 6500 rpm. Launch it at 2000 and it hooks up and goes. Launch it at 3000 and it blows the tires off of it. IMO it is perfect. You have to realize that I live in an urban environment with lots of stoplights and I needed a cam with good low end manners. I can shift it at 2000 rpm if I want and it pulls just fine.

Now it USED to be 240/249 with 108 LSA. That was WAY, WAY, WAY too much cam on the street.
what power are you making??? do u think i'm under carbed with a 670 street avenger?
 

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squidz said:
btw.... my compression should be around 10.0 - 10.2
...cam will work fine...
 

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You've already got the carb, so try it first. You can always go bigger....
 

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squidz said:
do u think i'm under carbed with a 670 street avenger?
6t9mach1 said:
Depending on your redline rpm and what the majority of the driving will be for this car, johnpro may be right. From my calculations, if this car is just going to be a street car you will be fine with your 670 if your redline will be between 6500-6900rpms. If you plan on taking this car to the strip a 750 would probably be a good compromise. Since you are going to run a dual plane intake you can get away with "overcarbing" the motor a little easier than you could with a single plane. If this car were only going to be a drag car then you would need a carb in the 800-880 range if redline was between 6500 and 7000 rpms. Hope this helps.
 
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