Help! I Don't Speak Cam!

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gorgerider

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I've never had to deal with anything like hopping up a V8. All my experience is with stock restorations. I've done a lot of searching on this site and come up empty. I see a lot of numbers associated with cam selection and simply don't know the language. I do know there are lots of options and manufacturers.

Is there another thread or other lead which explains the numbers and can help me select a hydraulic flat tappet cam for the following build on my '64 Dart conversion (street application):

'66 273 w/ 10.5:1 pistons (bore unknown)
Eddy 600 cfm carb
Eddy SP2P intake
920 heads, ported
Stock manifolds
Single 2 3/4" exhaust
'75 A833 3-speed OD
7 1/4" rearend

Thanks for your response. GR
 
I speak Jive....

[ame]https://youtu.be/fXSLcYQHqFQ[/ame]
 
gorgerider said:
I've never had to deal with anything like hopping up a V8. All my experience is with stock restorations. I've done a lot of searching on this site and come up empty. I see a lot of numbers associated with cam selection and simply don't know the language. I do know there are lots of options and manufacturers.

Is there another thread or other lead which explains the numbers and can help me select a hydraulic flat tappet cam for the following build on my '64 Dart conversion:

'66 273 w/ 10.5:1 pistons (bore unknown)
Eddy 600 cfm carb
Eddy SP2P intake
920 heads, ported
Stock manifolds
Single 2 3/4" exhaust

Thanks for your response. GR
Click to expand...


What are you looking to do with the car? Street? Strip? cruise?

Go with 260° - 275° advrtised duration
Lift between .450" - .500"

Go with 2 1/4" dual exhaust 2.5" max...
 
You will want the service manual for the car you are working on. It will have all the specifications of the motor you are working on including carb & cam information. It will be a good place to start when considering any mods to your motor. Good Luck
DR:coffee2:
 
 
I think the voodoo 250 would work well with street gears and the od.
If you have more than 3.55s i think the voodoo 256 would be great.
 
Rear axle ratio is important to consider as suggested above as you can help fill in low end losses with more gear....
 
Do you plan on taking advantage of the factory adjustable valve train and use a solid lifter cam, or are you going to wuss out and go hydraulic? If you're going hydraulic, I'm not even going to waste my time with a recommendation.
 
RustyRatRod said:
Do you plan on taking advantage of the factory adjustable valve train and use a solid lifter cam, or are you going to wuss out and go hydraulic? If you're going hydraulic, I'm not even going to waste my time with a recommendation.
Click to expand...
Ouch Ouch----said the guy who went hydraulicO:) Cant say I haven't been second guessing myself:banghead:
 
Thanks for chiming in, guys.

krazy: I tried speaking jive once, but hurt myself in the process. Also, I made an edit after you posted and stated the application was street. To tell you the truth, I haven't really made up my mind about single or dual exhaust. Since I'm not doing any bracket racing and won't likely be above 5K revs (at least not very often), my thought was the big single option would do OK.

DR: I downloaded a factory manual yesterday, but my Luddite self can't figure out how to unzip the file. As far as the build I listed above, it's based on usage and available parts. I know there are many opinions and preferences out there, but I'll try this package first. I can always change some stuff later (not that I want to - I'd rather do it right the first time).

64physhy: Thanks for the links. I'll be doing a bunch of reading tonight.

moturbopar and mgguner: The rearend is stock and so is the trans ('75 833). The rearend is from a '64 w/ slant six, I think a 170 w/ 904 automatic. All I know is it's a stocker. I also don't know the ratios for the 833. I know I have more research to do on this. The SP2P was chosen partly for low end torque.

RRR: As stated above in the initial post, I am going hydraulic. You've made it more than clear in another thread you disapprove of my engine choice. I respect your obvious devotion to this forum and experience. I just wish the public comments you make toward me and my project reflected something other than negativity and reflected more of the biblical teachings you espouse in your signature. Of course, you can always PM me should you wish to continue on your same course.

GR.
 
Call Hughes Engines, they have done this many thousands of times.
 
gorgerider said:
Thanks for chiming in, guys.

krazy: I tried speaking jive once, but hurt myself in the process. Also, I made an edit after you posted and stated the application was street. To tell you the truth, I haven't really made up my mind about single or dual exhaust. Since I'm not doing any bracket racing and won't likely be above 5K revs (at least not very often), my thought was the big single option would do OK.

GR.
Click to expand...


I found out with a 70 Dart with a 318 that the single exhaust was the biggest restriction on it. After replacing it with dual 2 1/4" exhaust with an h-pipe it really woke it up, even with stock exhaust manifolds and a 2 bbl. #-o

You should go with dual exhaust to get the full benefit of the cam and 4 bbl... :glasses7:
 
X2 on the dual ex and the early (92/early 93) magnum ex manifolds which have the ~2&5/16" outlets are an EXCELLENT choice & might run ~$100 +the ride & are well worth it. mandrel bends and as low restriction (loud) of muffs as you can handle and if you add glasspacks alongside the rear leafs in addition to muffs that will let you use a less restricted type (louder) muff(s) up front & still have a quiet enough pkg & have more performance from the less restriction
 
With street use, I'll assume you you mean a lot of cruising and roaming around in the hills, NOT street racing.... you will get better results if you define 'street use' more. Can you make your actual use plans clearer that just 'street use'?

In that case, you would like to go with a cam of not too much duration. If you go too short with a true 10.5 CR, you will end up with detonation problems. So how short you can go depends on if your compression ratio really is going to be 10.5:1. But such pistons as advertised for the 273 typically end up quite a bit lower in actual compression ratio.

So, to really answer your question, I would like to see what brand pistons you are planning on, and all details of what you plan to do around the combustion chamber. And the planned rear gear ratio does have a bearing on it....probably a 3.23 or 3.55 in that axle.
 
I appreciate your comments and questions. Sorry, it looks like I'm not fluent in "street use", either.

I live in the boons and will spend a lot of time on the freeway, "roaming around the hills" and only some time in town. My street racing days are well behind me. I'd like to set up for low-end torque, snappy up to 5K, and some fuel mileage (hence the SP2P).

I haven't bought the 10.5:1 pistons yet. I may bite the bullit and get Egge's, but I'll wait a while (cost is something of a factor). I will "balance" the head chambers by matching the volumes to the largest volume chamber, kind of like balancing a piston or rod. I will also try and fiddle with the piston and rod length to equalize the cylinder volumes. There's a great thread for that procedure on the site somewhere. I'll also try my hand at a home port tuning job and look into decking the block a little. I realize, as you suggest, a true 10.5:1 is likely unobtainable. If I get 9.5, I'm happy. And I'm not afraid to buy the spendy gas. I just don't want to have to add toluene.

I'll have to wait a bit to determine the rearend ratio. I also have to search out the trans gear ratios. I'm not sure of the wheel size, 13" or 14" (car is still 2 hours away and I'm waiting for a clear title before I pick it up). All I know is they're bone stock. I'm kind of concerned about keeping the speedo working accurately so the result will be close to stock ratio. I'm assuming a SBP, but will likely change to LBP when I get around to changing the rearend to 8.75", stiffening up the suspension, and converting to disc brakes.

It sounds like cam selection will be something I'll do after I get my CR dialed in and finalized. This thread was started to allow me to speak the language of camness in preparation for when I get down to selecting one.

Thanks. GR
 
Thanks for the clarification on the use..... 'street use' and 'streetable' tend to mean different things to different people. Your 'street use' is very similar to mine BTW, even back when I was street drag racing. There are a variety of cams that will do what you want.

It would be worth your while to read this thread. It contains a lot of discussion of this very subject.

http://www.forabodiesonly.com/mopar/showthread.php?t=330134

Post 31 in that thread has links to Toolmanmike's 273 work, in which he explores the Egge and Kanter and old TRW piston CR's for the 4 bbl 273 pistons; the CR's are quite different, with the Egge's being the lowest. Limiting your real SCR to 9.5:1 is the proven conventional wisdom for your type of engine.
 
Carb is Eddy 1405.

I can't track down a set of TRW 10.5:1 pistons. Any known sources? I do see the Kanters at a price $356. I also see Sealed Power slugs included in engine kits.

I've also been reading some about cylinder quench and A/F mixture efficiency. What would be the proper top of piston to top of block depth for this 273? (I'll continue looking on the build threads).

nm9, I've been looking for the compression balancing thread all morning. Thanks for the link. I've popped in and out of toomanmike's thread, but obviously need to study it further.

Thanks to all for the links to the cam info threads. I think I have enough to get a throrough handle on the subject and be able to speak "conversational cam".

GR.
 
gorgerider said:
Carb is Eddy 1405.

I can't track down a set of TRW 10.5:1 pistons. Any known sources? I do see the Kanters at a price $356. I also see Sealed Power slugs included in engine kits.

I've also been reading some about cylinder quench and A/F mixture efficiency. What would be the proper top of piston to top of block depth for this 273? (I'll continue looking on the build threads).

nm9, I've been looking for the compression balancing thread all morning. Thanks for the link. I've popped in and out of toomanmike's thread, but obviously need to study it further.

Thanks to all for the links to the cam info threads. I think I have enough to get a throrough handle on the subject and be able to speak "conversational cam".

GR.
Click to expand...


For 273 pistons, try Egge....
 
There some 273 pistons on my CL that came from Egge but I think it expired.
 
gorgerider said:
I can't track down a set of TRW 10.5:1 pistons. Any known sources? I do see the Kanters at a price $356. I also see Sealed Power slugs included in engine kits.

I've also been reading some about cylinder quench and A/F mixture efficiency. What would be the proper top of piston to top of block depth for this 273? (I'll continue looking on the build threads).
Click to expand...
The TRW's are long out of productions so you can only find some used or NOS on eBay perhaps. The Egge's are as mush or more than the Kanter's... welcome to the world of 273 pistons!

TMM might have those heights in his thread.
 
I used Egge for mine. Called them and they had 6 sets of .040 over 10.5:1 pistons on the shelf. I think it is because not many of us want to go .040 over. .030 seems to be the witching number. You will be glad you did it on startup day though!
Cheers-DR:coffee2:
 
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