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06-05-2020, 03:34 PM | #1 |
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Join Date: Feb 2017
Location: Dothan, AL
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Cam & transmission question
My 1942 Ford GPW is all original and love it, but....
I have built a 49-53 1CM, with 4" stroke crankshaft, stock EAB cam, milled heads to .045 clearance, and 2GC Rochester carb, chevy distributor modified for flathead with AOD transmission. I'm putting this into 39 ford pickup that will be on the road soon I hope. I have dual exhaust with Red's headers. I'm considering going to a cam something other than stock (wife and daughter love sound of engine with hot cam) and wanted some opinions/feed back from those that are running an automatic transmission with more than a stock cam. I do parades from time to time, very slow, lot of stopping; along with city driving. By the time I finish a parade with the GPW I can hardly walk and looking for something fun, with sound that is the same day after day cranking and driving. Just asking before I jump off the cliff. Thanks for all comments. |
06-05-2020, 06:15 PM | #2 |
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Location: Chester Vt
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Re: Cam & transmission question
Probably a Nax #1 would keep most of the low end torque. However an EAB cam could use your stock lifters ans save sime money. Chancing a cam in a stock street engine is a VERY expensive move.
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06-05-2020, 06:21 PM | #3 |
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Re: Cam & transmission question
You won't be happy with any cam other than stock for what the planned use is.
If you need a lumpy idle, just pull the choke out a bit. |
06-05-2020, 07:28 PM | #4 |
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Location: Dothan, AL
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Re: Cam & transmission question
Thank you very much.
If I removed the glass pack mufflers and ran straight pipes from headers out the back maybe that would give me more cam thump sound. Anyone got a sound video of stock engine and straight pipes? |
06-05-2020, 07:32 PM | #5 |
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Re: Cam & transmission question
Put a speaker under the hood and play a lumpy engine sound with your phone through it.
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06-05-2020, 11:59 PM | #6 |
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Re: Cam & transmission question
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Enjoy yer day. Tom Hate can't fix what it started. |
06-06-2020, 12:41 AM | #7 |
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Re: Cam & transmission question
Forty years ago, I walked up to a cute Model A coupe at a swap meet that sounded like it was just sittin' there with the stock engine idling. Looked inside the open window and the guy had a tape recorder sitting on the seat, playing the A-Bone song at top volume. It would even rev-up every fifteen seconds or so. Put a smile on my phizog! DD
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06-06-2020, 09:15 AM | #8 |
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Re: Cam & transmission question
What’s the “A-Bone song”? Did a google search, nothing turned up.
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06-06-2020, 03:53 PM | #9 |
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Re: Cam & transmission question
With a lumpy cam your low end torque will suffer. Trucks need low end torque. There is always a trade off with cams. if you want high end performance then your good to go with a lumpy cam.
https://www.youtube.com/watch?v=cSZ0jdc36KQ Last edited by rotorwrench; 06-06-2020 at 04:00 PM. |
06-06-2020, 05:46 PM | #10 | |
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Re: Cam & transmission question
Quote:
It's just the happy sound of a Model A engine caught idling on a tape recorder, with intermittent periods of revving-up to break the monotony. I don't believe "Google" has yet discovered this particularly-delightful acoustic! DD |
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06-07-2020, 12:55 AM | #11 | |
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Re: Cam & transmission question
Quote:
I think you can make a hot cam work with a couple of modifications. First, do you have EAB heads (from a Ford, not Merc)? The Mercury heads (0CM, 1CM, EAC) have larger chambers than Ford (8BA, EAB) so using Ford heads and milling them gives more compression, which helps with a hot cam. Also more ignition timing at idle will get some torque back. So recurve the distributor to keep total advance the same but have more initial timing and have the advance start sooner. The added compression and timing will make it bark a little better, too. Check out Comp Cams Thumpr series. They're supposed to give a "drive-in" idle with decent drivability. Next, go to a higher stall torque converter. This will lessen the 'drag' on the engine at idle and let the engine rev a little higher when taking off to get further into the powerband. You don't need a race converter, just one with a little higher stall speed. Call one of the converter companies. A nice thing about the AOD converter is that it has partial lockup in 3rd and full lockup in 4th (overdrive) so fuel mileage and drivability on the highway are not affected, and the pipes will play sweet music. Finally, just make sure you have a good trans cooler for those parades, where extended running just above idle can make a lot of heat. |
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06-07-2020, 07:36 AM | #12 |
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Re: Cam & transmission question
One thing about a cam change is cost. Bottom line is about $500 +/- Then you have to completely dissesemmble the valve train. All for Rump, Rump??? The choke trick was my favorite!!
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06-07-2020, 08:56 AM | #13 | |
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Re: Cam & transmission question
Quote:
The problem with the choke trick is that you are washing down the cylinders with raw gas, diluting the oil, and fouling spark plugs. That's engine abuse |
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06-07-2020, 09:03 AM | #14 |
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Location: Dothan, AL
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Re: Cam & transmission question
I do have EAB heads, and bored to 3 5/16. Distributor already set up for flathead. I really appreciate all the opinions and comments they will help me determine what route I take. The auto trans is new to me and how it will perform behind the flathead. I have always been told the only stupid question is the one you don't ask.
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06-07-2020, 09:21 AM | #15 |
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Re: Cam & transmission question
My avatar has a stock engine with electronic distributor and 2 2s running progressively. I have 2.25” straight pipes, no mufflers, and MANY GUYS have thought I was running a hot cam and/or the engine was hopped up in some way. Stock cam, stock bore, 3 3/4” crank, stock intake with Y adapter for the 2 94s. Exhaust exits before the rear wheels ....
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06-07-2020, 01:05 PM | #16 |
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Re: Cam & transmission question
Well . . . I can't help myself . . . I will always run a hot cam and 'Yes' it will reduce the torque/HP at low speed. But - I build HotRods, not stock engines . . . just the way I prefer them.
I think the suggestion of a mild stall in the converter is good and I think you can still get away with a somewhat lumpy cam - like a 1007B, which Pete can grind for you. It is always a trade-off, if you want a cam that makes horsepower at higher RPM, has that "lumpy rumpity rump" sound, then it is taking HP/Torque away at lower RPMs. Bigger cubic inches help the situation and having higher compression helps the situation (low speed driveability). But Hey - a high-performance flathead is supposed to have that "drive in" sound if you ask me! |
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