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Discussion Starter · #1 ·
I need help finding the cam to use. I want a cam that is going to give me an awesome idle, but I also want performance. The heads I have are 62cc combustion chamber 170cc intake runner. I have no intake yet so any help there wouldnt hurt either. Guys have told me to use a .480 lift cam. I will be running gear drive instead of chain. Any other info you need let me know. Thanks.
 

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need to know: heads, compression, intake, carb, exhaust, trans, rear gears, tire size, viehicle, intended usage, intended fuel, rod length (optional), desired cam type (flat or roller, hyd. or solid), and zodiac sign.

The last item is a joke- the others are not.
 

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Use a 28cc dish piston such as this with your 62cc heads....
http://kb-silvolite.com/performance.php?action=details&P_id=91
for a static compression ratio of 9.0:1
Call up CompCams and order a 12-600-4 "GK" kit. This will give you the Thumpr camshaft, flat tappet hydraulic lifters and the gear drive in a "kit".

Dynamic compression ratio will be 7.91:1 and you'll be able to operate on junk pump gas with a thumping idle.

Note to others: Tired of fighting it. :rolleyes:
 

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Discussion Starter · #4 ·
need to know: heads, compression, intake, carb, exhaust, trans, rear gears, tire size, viehicle, intended usage, intended fuel, rod length (optional), desired cam type (flat or roller, hyd. or solid), and zodiac sign.

The last item is a joke- the others are not.

I dont remember what type of heads they are just know that they are 62 cc combustion chamber 170cc intake runner. Compression 10:1, Will put RPM airgap intake, carb (650-750?), exhaust, rear gears, tire size will put together how ever I need to. I would like to drive it on the street, but I want to play if I want also. Intended fuel high octane pump gas. Rod length 5.7. Would like hyd.
 

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Discussion Starter · #5 ·
To late rotating assembly (minus cam lol) is already installed. Saw another post you did the pistons are flat top with 2 eyebrows. According to sealed power they are 10:1 with 64cc heads so with 62cc's it should be a bit bigger.
 

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TI, I guess you're getting to old for this- someday I feel liek I am and I'm still a pup. :mwink:

If you're running a 383 with 2 VR's and 62cc chambers then your intended fuel just went up to some sort of race fuel or E85 at the very least.

That is not a street friendly compression ratio.

and 62cc and 170cc intake runner is liek telling me they are cast iron- it helps, but not much. What heads are you running?

170cc runner is almost definitely poorly matched to a 2VR flat top piston though unless you have some serious race heads developed by Widmer or something- in which case you would not be here asking for a cam recomendation.

Also, hyd. cams typically float around 6500 RPM, which is fine for a street engine, but not for the compression you probably have.

The point of all of this- you need new heads or new pistons.
 

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I'll give you the elementary explanation.....there's way more to it, but you should get the idea from this.....

The torque converter bolts to the flexplate, drives the transmission pump and controls the point where the motor stalls up against the brakes. If you apply brakes in drive and rev the motor until it won't rev any higher, that is the stall speed of the converter as read on your engine tachometer. Most stock converters will allow the motor to rev to maybe 1200 to 1500 rpm's.

The 12-602-4 Thumpr cam is ground at the factory to provide an operating range of 2500 to 6400 rpm's. Under 2500, it will be very weak, so you want to use a looser torque converter that stalls the motor at 2800 (called a 2800 stall converter) to 3000 (called a 3000 stall converter) rpm's so that you get the motor past the dead zone that will be present from idle to 2500 rpm's.

Install an auxiliary transmission cooler in front of the radiator. Run the line from the transmission pump (front line outlet on the transmission case) to the auxiliary cooler, then out of the auxiliary cooler to the transmission cooler that is in the bottom of the radiator. Out of that cooler and back to the transmission case (rear line inlet on the transmission case).
 

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383 cam

I was thinking of posing this question as well, my engine is built already and just looking for feedback to see if I will need to rethink my choice. I am building a 1935 chevy master coupe, not sure what finished weight will be, it will be a full fenders, & interior, rumble seat, a/c. p/s. p/b. I want good performace and drivability with the ability to "get with the program". I hope for a little rump rump. But really want to be able to let my wife drive it. (yeah right).
Heres the specs I know:
383 stroker kit 4 bolt main.
9.5:1 comp ratio
gm zz 4 cam 208 degree intake / 221 degree exhaust
.474 intake / .510 exhaust
roller lifters
1.5 ratio rocker arms iron vortec heads (64 cc?) 1.94/1.50-inch
edelbrock tripower intake
rodchester carbs
700r 4 transmission
stall converter?????
3:73 posi rear end
rear tires height approx 27 or 28 inches tall.

Will I need a stall converter? Should I have choose a different cam.

I am not a mechanic or a racer... don't get real technical unless necessary,

Thanks
 

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35prog said:
I was thinking of posing this question as well, my engine is built already and just looking for feedback to see if I will need to rethink my choice. I am building a 1935 chevy master coupe, not sure what finished weight will be, it will be a full fenders, & interior, rumble seat, a/c. p/s. p/b. I want good performace and drivability with the ability to "get with the program". I hope for a little rump rump. But really want to be able to let my wife drive it. (yeah right).
Heres the specs I know:
383 stroker kit 4 bolt main.
9.5:1 comp ratio
gm zz 4 cam 208 degree intake / 221 degree exhaust
.474 intake / .510 exhaust
roller lifters
1.5 ratio rocker arms iron vortec heads (64 cc?) 1.94/1.50-inch
edelbrock tripower intake
rodchester carbs
700r 4 transmission
stall converter?????
3:73 posi rear end
rear tires height approx 27 or 28 inches tall.

Will I need a stall converter? Should I have choose a different cam.

I am not a mechanic or a racer... don't get real technical unless necessary,

Thanks
IF you run that cam you do not need a higher stall conv. I woul dnot run that cam unless you plan on running nitrous or are running stock manifolds through 2.5" single exhaust and ctalytic convetors's- because it has too much exhaust split otherwise.
 

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Faulk21NG238 said:
Yes they are cast iron so what kind of heads are needed or what kind of cam can I use with this set up?

I was looking around at cr's for this set up and it looks like I am already at 11:1.
Yeah, the thumpiest Thumpr they make isn't enough cam to work with 11:1 SCR. Dynamic compression ratio would be too high to work with pump gas. Could have made the 12-602-4 work at 10:1.
 

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engineczar said:
Please explain this statement, I'd like to hear your reasoning

a 383 with a 2VR piston even with a large chamber head you're going to end up with at least 10:1 compression, with a 64cc chamber or less it goes even higher. These compressions will dicate running longer durations on your cams, which will allow higher lifts... Your heads will stall with that small of a runner and you will be leaving a lot of power on the table- especailly in the higher RPM's.
 

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Unfortunately you're comparing apples to oranges. You can always use more airflow, which needs more cam, which needs more compression, which needs more airflow, which needs more cam, which needs more compression, which needs more.................. until you no longer have any money in your wallet.
Every post a person makes doesn't need to end with aftermarket heads and a big roller cam. For the O.P. a 170 although on the smallish side for 383ci isn't going to run out of airflow and choke. At least not in the RPM range he's looking at. Are you leaving hp on the table? Unless you're building pro stock engines then you're always leaving hp on the table. I'd be a little more concerned with the compression ratio he has if he's planning on running pump gas.
 
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