Picking a cam
Thread Starter
Instructor
Joined: Jun 2005
Posts: 156
Likes: 0
From: Liverpool NY
Picking a cam
I'm building a 400 for my C3. It's 40 over with aluminum 2.0/1.6 heads, Hooker headers with side tubes, air gap dual plane manifold and a 750 Edlebrock carb. I'd welcome any information I can get on picking a cam for this motor or advice on how to go about picking a cam.
Thanks
Thanks
Drifting
Joined: Apr 2002
Posts: 1,736
Likes: 37
From: Stockton Ca
Getting Started?
We have some very serious engine guru's here. The first thing they will want to know is your budget and your driving style.
I'm not going to give advice on your cam choice.
The best advice I ever heard is:
Do your research and find what you think is the perfect cam, then go one size smaller!
Hopefully others will jump in w/their experience.
Ricisan
I'm not going to give advice on your cam choice.
The best advice I ever heard is:
Do your research and find what you think is the perfect cam, then go one size smaller!
Hopefully others will jump in w/their experience.
Ricisan
Melting Slicks
Joined: Jul 2006
Posts: 2,285
Likes: 487
From: Salmon Arm, BC
Yes, driving style and RPM range along with an indication of flat tappet or roller. I like rollers myself, but have also had good luck with flat tappet.
Do you want a smooth idle, noticable lope, choppy?
I have a 400 as well and chose a Comp HR276HR 224/230 .535 IN .544EX with 1.6 roller rockers.....can't tell you what I think, as its not installed yet
Instructor
Joined: Jun 2008
Posts: 102
Likes: 0
From: Coldbrook Nova Scotia
Engine details are only part of the equation..Rear end gearing and stall speed will also play a significant role..If it,s a manual car then stall speed isn,t a concern.Now back to the engine what,s the compression ratio,what size runners on the heads? is it a daily driver or weekend cruiser? I,m not trying to be difficult but all these factors and many,many more will need to be considered ..not to mention you can go with a hydraulic roller or mechanical or a solid or flat tappet hydraulic. The good thing is there,s alot of choices unlike other engines out there.Just remember it,s not an exact science no camshaft is going to give you optimum performance from idle to red line,but pick one that will match your cruising rpm and works with all of your other components and you will be on the right track..Good luck.Got me thinking about another cam change..
Race Director
Joined: Jan 2000
Posts: 13,014
Likes: 2,257
From: Corsicana, Tx
2020 C2 of the Year - Modified Winner
2020 Corvette of the Year (performance mods)
C2 of Year Winner (performance mods) 2019
2017 C2 of Year Finalist
The cam will almost completely decide the characteristics of the motor. It will either compliment the other parts....or be a total stone. That's why there is so much discussion about them.
What heads? How big are ports? Any port work? Flow #'s?
What compression?
What trans?
What gearing?
Converter?
What mufflers are in those sidepipes?
What size tubes?
How much highway driving?
Do you want to be a hero at the dragstrip?
A/C?
P/S?
P/B's?
How smooth does it need to idle?
What kind of gas can you get?
Quench area (piston deck height and head gasket)
As you can see..there is a lot of variables and the cam can be tweeked to suit all of them.
Give us a little more info and I'm sure someone here will have a combo that is similar and we can narrow down some choices you'll be happy with. Don't take the easy way out on this item.....proper cam choice will have you walking away from the other guys!
JIM
What heads? How big are ports? Any port work? Flow #'s?
What compression?
What trans?
What gearing?
Converter?
What mufflers are in those sidepipes?
What size tubes?
How much highway driving?
Do you want to be a hero at the dragstrip?
A/C?
P/S?
P/B's?
How smooth does it need to idle?
What kind of gas can you get?
Quench area (piston deck height and head gasket)
As you can see..there is a lot of variables and the cam can be tweeked to suit all of them.
Give us a little more info and I'm sure someone here will have a combo that is similar and we can narrow down some choices you'll be happy with. Don't take the easy way out on this item.....proper cam choice will have you walking away from the other guys!
JIM
Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
Many things are considered such as C.I., Trans. (stall if auto.), rear gears, heads, C/R, exhaust, intended usage, rpm range normally used & what the owner wants. Also considered is car weight & tire diameter. TD may surprise some, however it affects overall rear ratio, for example if much taller slicks were used.
As one who has answered many cam topics, many times not even minimal info. is given so one has to check their profile, sig., even check their topics & posts.
Cam selection is critical, you can think of the cam as the engine's mechanical program & it's necessary to have matching heads, etc. for flow in & exhaust for flow out.
As one who has answered many cam topics, many times not even minimal info. is given so one has to check their profile, sig., even check their topics & posts.
Cam selection is critical, you can think of the cam as the engine's mechanical program & it's necessary to have matching heads, etc. for flow in & exhaust for flow out.
Le Mans Master
Joined: Nov 2008
Posts: 5,691
Likes: 12
From: columbus oh
I'm building a 400 for my C3. It's 40 over with aluminum 2.0/1.6 heads, Hooker headers with side tubes, air gap dual plane manifold and a 750 Edlebrock carb. I'd welcome any information I can get on picking a cam for this motor or advice on how to go about picking a cam.
Thanks
Thanks
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Melting Slicks
Joined: Jul 2005
Posts: 2,545
Likes: 3
From: 406ci SB, AFR 180 Heads - 490 HP @5,600 RPM 529 lb-ft @ 4,100 RPM
I'm running a 406ci with a Lunati cam 0.480 lift, 230 degree duration @0.050. To get more out of the cam I used Comp Cam Pro Magnum 1.6.1 roller rockers which increased the lift to 0.512 and added 2-3 degree. Very happy with the Lunati cam and my whole set up.
Good Luck with your choice.
Good Luck with your choice.
Le Mans Master
Joined: Nov 2008
Posts: 5,691
Likes: 12
From: columbus oh
..i also agree with you the importance of comp. ratio
