How to match heads with camshaft - Team Camaro Tech
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post #1 of 24 (permalink) Old Mar 21st, 11, 05:06 AM Thread Starter
adrian
 
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Question How to match heads with camshaft

i am new to building motors but love hp lol. i dnt know how to match cam with heads. i have looked up a few posting about this already but the only answers i see is "well what is this vehicle gonna be used for", and "trickflow and patriot makes good head", and "whats ur budget like". i know those are very important questions but where is the ANSWER to the question i am asking lol. lets say money isnt and issue and neither is hp. how do u match a cam to heads, like what numbers am i trying to look for or what am i looking for when trying to match heads and cams lol. im trying to order heads and a cam from summit but none of the numbers from a cam match any numbers from ne heads. how do i match them? here is some info on my motor. its a 454 all stock except headers and a holley 750dp . i believe its a 70-80s model. my plans for this motor is for it to tear up the street and smoke the high school kid that thinks his 2010 mustang gt is fast lol. it will see sum strip, and it will be on the street ALOT not only the weekends. what is chamber cc and intake cc and how do u match that with a cam, im so confused and lost lol.
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post #2 of 24 (permalink) Old Mar 21st, 11, 08:42 AM
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Ron
 
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Re: How to match heads with camshaft

A 70 to 80's 454 does NOT have much more then a 7.5 to an 8:1 Static Compression using the Stock OEM Flat Top Pistons. You're best Cam choice is between a 266 to a 270H-10 and short shift at 5000rpm hoping to get it all in by 6000rpm before the Valve Train breaks. 373's or 355 rear gear ratio is about ideal for the 1/4. You'll never reach the end of the 1/4 with an 7.5:1 Static Compression 454 running 4:10 Gears.

You need domed Pistons (9.5 to say 10.5:1 Static Compression Roller Rockers and say a 278 or 282H-10 Cam with recommended Valve Springs to get the Revs above 6000rpm and maybe it will carry 4:10's to the end of the 1/4. Pending money, you can hit 7000rpm with a forged crank with a 10.2 to 10.5 Static Compression with either a SFT or SR Cam on Pump Gas.

A Holley 750 DP/say and Edelbrock RPM with headers can get you 6000rpm but if you after 6500rpm you need an 850 to 900 cfm. (Annular Booster Carbs give a much better Throttle response and you can usually get by with 50 CFM Smaller say an 830)

Check out Patrick Kelley's DCR Calculator here: http://www.empirenet.com/pkelley2/DynamicCR.html

and Comp Cams CamQuest Software Here:http://www.compcams.com/downloads/register.asp

We really need the Block and Head Casting #'s, Is Crank Forged (A Cast Crank can get you to approx 6500rpm), Transmission and rear gear ratio and how you intend to use the ride before commenting further - After Market Heads are not really necessary; however, Alu-Heads are much lighter for better handling where the Engine has to be 0-Decked.) - Good Luck ;o)

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Last edited by Z15CAM; Mar 21st, 11 at 12:29 PM.
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post #3 of 24 (permalink) Old Mar 21st, 11, 09:09 AM Thread Starter
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Re: How to match heads with camshaft

i dnt think i can getthe black number cuz its in the vehicle and rearend gears i can get those switched out. but if i went to summit right now how do i match up heads with a cam
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post #4 of 24 (permalink) Old Mar 21st, 11, 09:27 AM
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Ron
 
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Re: How to match heads with camshaft

Quote:
how do i match up heads with a cam
The question is redundant and impossible to answer. Static Compression, Strength of Rotating Assembly, Type of Induction and Gearing ... etc is what determines Cam Selection - Please read my post and Download the Software with the links I've provided. It will give you much more understanding - Do the Home Work ;o)

PS: The Block Casting Numbers are on the Top of the Bell Housing Boss just behind the Distributor and the Head Casting Numbers are easily read with the Valve Covers removed. Note: The large oval port 820, 781 and 049 Head Castings are great performance heads if you have them. Many Flat top Piston 454's have been topped with Closed Chamber 396 Smaller Combustion Chamber heads to up the static compression.

To top it all of you need to know what the Dome Volume of the Pistons are which requires the removal a Cylinder head at which time you can CC the Cylinder Head Chamber Volume..

The Engine Code written on the PSGR Deck just behind the alternator can supply us with the exact Year and Model the engine came out of and if the motor is stock will tell us info re: piston along with the static compression.

If the motor has a History perhaps the previous owner can supply you with most the information but I personally never trust it.

There are just too many variables in your Question as you require the Specifications as I've outlined above to Select a Cam using Mfgr's Software. Head Gasket Thickness, Distance Piston is down in the Bore, Cylinder Head Volume, Piston Dome, Bore Dia & Stroke, Induction, Dynamic Compression Vs Pump Gas, Transmission, Gearing and what do you want out of your ride are critical factors when choosing a cam.

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Last edited by Z15CAM; Mar 21st, 11 at 12:48 PM.
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post #5 of 24 (permalink) Old Mar 21st, 11, 09:28 AM
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Re: How to match heads with camshaft

Comp has a VERY good cam selector on their website.
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post #6 of 24 (permalink) Old Mar 21st, 11, 11:24 AM
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Re: How to match heads with camshaft

Adrian, listen to Ron. There is a lot to deciding on a cam and head combination. Compression and rear end gearing are major factors.

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post #7 of 24 (permalink) Old Mar 22nd, 11, 03:12 AM Thread Starter
adrian
 
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Re: How to match heads with camshaft

thanks guys for the info and help, im just starting to geting into build engines and i want to learn more b4 i make my purchases. il take a look at the links and try to get the numbers for everything.
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post #8 of 24 (permalink) Old Mar 22nd, 11, 12:41 PM
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Re: How to match heads with camshaft

As stated above, many factors will determine what's best.

So, as an example, I'll suggest:

If on a budget (454 with 425-450 HP):

049 GM Heads with big valves
10:1 CR
280H Comp's Magnum Cam

If not on a budget (454 with 500 HP):

AFR Rectangle Port 315cc heads
10.5:1 CR
280-HR Comp's Retro Roller

3.73 gears in back would be ideal for either of the above. Either would be a very streetable combo that will pull vacuum for your brakes and would make power from 2000-5500 RPM.

You could destroy your rear tires at will and any new Mustang, but who would you brag to about that?

Last edited by Straight-line-69; Mar 22nd, 11 at 02:36 PM.
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post #9 of 24 (permalink) Old Mar 26th, 11, 02:13 PM Thread Starter
adrian
 
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Re: How to match heads with camshaft

im not the type to brag i just stay quiet and let the hp do the talking lol. and where can i find 049 heads or does my motor have them already? and what size of valves should i order to get this compression?
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post #10 of 24 (permalink) Old Mar 26th, 11, 02:21 PM
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Re: How to match heads with camshaft

An identifer is the head casting number and it's located under the rocker arm cover, or valve cover, same item.
Remove the cover and there will a string of numbers, seven of them. Either post them here for another member to identify or use a search engine for Chev big block casting numbers and follow the prompts.

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post #11 of 24 (permalink) Old Mar 26th, 11, 04:11 PM
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Re: How to match heads with camshaft

Adrian, we have said it to others before. Study. Buy a book. Learning from engine builders is problematic. Most won't have the time or care to extend the effort required to teach you their craft. An apprenticeship/school is the quickest way to learn this stuff. A book is good such as "How to Hotrod a Big Block Chevrolet" but you would still need basic knowledge to grasp the material.

To help with your last question, valves have nothing to do with compression ratio. They're just what lets the air-pump work. Yep, an engine is nothing but an air-pump.

What we are also trying to politely say is we can't teach you from the ground up on this or any other forum. We can point you in the right direction with specific questions but not with knowledge that takes many years to learn. No one here learned this stuff overnight. And we are all learning more each day. Kinda like sailing.

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post #12 of 24 (permalink) Old Mar 26th, 11, 04:24 PM
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Re: How to match heads with camshaft

Adrian, from what you've said it sounds like you want to leave the motor in the car for now; you don't want to rebuild it yet.

I would recommend buying the edelbrock E-Street heads; about $1500. They have smaller combustion chambers at 110 cc and that will raise your compression 1 point, probably to 9-1.
Plus you will save 90 pounds of weight !

Stay reasonable on the cam, something like I bought : 219/229 duration and .510 lift.

That should put you around the 450 hp mark if everything else is matched.

Good luck !
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post #13 of 24 (permalink) Old Mar 26th, 11, 04:57 PM
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Re: How to match heads with camshaft

Am really surprised by some of the answers you got so far, Adrian. It's not all that hard to do.

What you must know is what heads you have for sure. Have they had any work done to them? Ported? If they are stock, you should be able to find the airflow charts for them. If they were ported by a pro, hopefully you'll have the flow bench results.

Head flow is usually measured in cfm at a certain cam lift. If your cylinder head's airflow continues to increase up to .500 lift then does not go up at higher lift, then you know the amount of lift you want on your cam. .500. At anything more, your heads cannot take advantage.

Are you running an automatic or 4 speed? Do you want a smooth idle or a lumpy idle? These two questions will help determine the duration of the cam. Longer duration cams have that nice lumpy idle that many people love, but they don't produce a lot of vacuum and their powerband usually is quite a bit higher than your idle speeds (in the range of 2500-3000). This means they don't like power brakes and they aren't compatible with stock stall speed torque converters. Smaller duration cams usually have a powerband between idle and 5500 rpm or 1500-5500 rpm. They make good vacuum numbers and they will work fine with stock converters in an automatic.

The smaller the port volume on the heads, the faster the air/fuel mixture
moves thru the heads and fills the combustion chamber. Larger ports flow more air but at higher rpms. Again, how fast will you be spinning this engine? Big blocks don't like high rpms. Modern cylinder head designs are excellent at flowing large amounts of air. Since most of the time your engine's valves are somewhere between full lift and sitting on the valve seat, you want to look at what heads flow the most between .100 and .400 lift. The smallest port volume that flows the most between these lifts is the head you want.

As far as compression ratio, the cam makers can tell you what CR you need for the cam you have in mind.

Good luck.
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post #14 of 24 (permalink) Old Mar 26th, 11, 05:18 PM Thread Starter
adrian
 
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Re: How to match heads with camshaft

thanks everyone for the answers and time but i just found out i have a craked head. i dnt have the money buy a new set of $2000 heads and the labor cost, i have spent two years trying to fix a oil leak problem it had with a performance 350, so i ended up switching over to this 454 and after two years i finally got her running atleast and now not even a week into enjoying her i find this out so i think im just gonna sell her for 3000 if i can and just move one to sumthing else, kind of heart breaking when u spend all the time and money for nothing. i would like to say ive gained alot of knowledge and experince from this project. once again guys thanks
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post #15 of 24 (permalink) Old Mar 26th, 11, 05:19 PM Thread Starter
adrian
 
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Re: How to match heads with camshaft

and i know i posted a thread about how to match heads with cams but it wasnt to buy them it was just to learn sumthing
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