i built a few SBC in my time (early eighties) now i am astounded by this "million dollar machine" that does it all by computer. we first tested the crank bore and alignment was perfect on 1972 400' SBC. standard bore.now they mount the block in machine and every dimention is off centerline of crank!!! the deck height was way off and tapered now .005 across the board on both banks also exactly 90 degrees. the cam bore coincided with crank alignment but bores were off in center to center of bore as a matter of fact number three cylinder just clean at .030 OS with torque plate hone . block looks like a mirror!! i used scat forged crank,H-beam rods full floating on probe forged flat top pistons.rings are HP hastings 1/16,1/16,3/32 . i was not sure on cam i went for Lanati #10021 hydraulic roller with duration 278/288 @ .050 232/242 lift 507/507 with 1.5 rockers .i am using 1.6 so add a some lift on AFR heads , LSA.112 .compression is 10.4 .this is strictly a street car .sunday drive,car meets,vet functions

 

i am looking for advise on this camshaft from Mako,straub,mike ward as to whether this was the right choice. i have no experience with roller cams. nor the need for special fuel pump rod.alot to learn and don't want to find out hard way.

 

Well I'm not Mako, Straub, and certianly not Mike Ward, but I also have a 406 in my car with a cam very similar to what you have. Mines a Comp XR276HR.....224/230 @ .050" and I'm using 1.6 rockers also so I get .535/ .544 lift with those. Compression ratio is right at 10.3 as well. My engine has great street manners, loads of torque, and pulls great up to 6000 RPM.....and I only have vortec heads, with your AFR's you'll get an added kick for sure.
I think the cam you have chosen will work fantastic on the street, with the occasional blast up to 6000 RPM to clear things out. Enjoy....

 

With the 406, AFR, 10.4 comp, 3.55 gears I would go single pattern more lift. This is an awesome match for your build.
http://www.compcams.com/Company/CC/c...?csid=152&sb=2

 

mako thanks for the reply .i wanted to go with a cam with 2000 to 6000 best operating range on street. 2500rpm seen like quite a bit of a torque converter for street.well i purchase the AFR heads on your recommendation over Dart. the intake,exhaust,and CC are CNC ,very impressive however when i took apart to clean and check spring pressure,height i did find one half of one valve retainer cracked.company replaced immediately. do i need need special fuel pump rod ,distributor gear with roller cam?

 

You can drop the operating range numbers listed 500 RPM because of your 406 CI. The rating is for a 350. The operating range is determined by the duration @ .050 and LSA. The lunati has an intake duration @ .050 of 232 LSA 112. Comp magnum has a duration @ .050 of 230 LSA 110. Similar manners and operating range (within a few hundred RPM at both ends). Magnum's Intake closing point, lift and single pattern match your build specs and compression better. If you have a stock pressure, volume fuel pump your pushrod is fine if not you need the bronze tipped pushrod or roller tipped.. You need a melonized dist gear.
http://www.summitracing.com/parts/ACF-10456413/

 

I would not run that wide of an LSA. the events need to take advantage of the heads. They flow air quickly so we need to get the valves open and shut quicker.

AFR heads have a high I/E ratio. That much split at .050" will blow the power right out the pipe.

 

Single pattern, tighter LSA, Little smaller duration @ .050, Proper intake closing point for your compression and build, Proper RPM range for your gearing, lift to take advantage of head flow capabilities. You can go custom cam but for an off the shelf the Magnum I speced should be good to go. You could go the next smaller Magnum 280 HR but your borderline to run pump gas then, actual operating range will be about 1500-5000 RPM and 525 lift will not take full advantage of the heads.

 

Not sure what H-Beam rods you're running (probably 6" Scats) but you may be looking at a small base circle cam. Not a problem especially with a roller.

As with everything else, check your clearances. You'll want .050 or more from the cam lobes.

 

Yes i am running 6" scat forged rods and i have not checked cam to lobe clearance yet.my area has 93 octane every mile and 94 at marina. I will use 93 Shell high test which is my normal supply. I see you gentleman don't like my cam choice and i went out of my way to purchase 112 LSA!! Those AFR heads look huge 2.05 intake and 1.60 exhaust but without valves in head these heads appear to be cut out from valve bowl to intake port and exhaust is cut into upside down D . These are 195 heads what do the 210 cfm heads look like! I have 17/8" primary pipes into 4" collectors and intake manifold is "crosswind" dual plane with cut out in center divider. Back to cam ,sorry trying to make light of this new cam technology as when intake valve opens i don't understand why i would lose power being conservative ,mainly did not want a wild torque convertor on street car.

 

Intake closing point determines how much A/F charge is trapped. With 10.4 to 1 compression you need an intake closing point of 63 to run pump fuel if everything is optimal, tune, temperature, timing, A/F ratio, quench. I tend to err on the side of caution always as usually nothing is perfect. Nothing is worse than putting it together then having detonation issues and having to detune it to drive it. I just calced it out. You can run the Magnum 280. Intake closing point 66. Magnum 286 is intake closing point of 69. Will likely run on midrange, it will make more power across the board. If you go too small on duration and lift you leave a lot of power on the table and possibilities of detonation. Too wide of split power out the tailpipe like Chris said. Just because the listed operating range is 2500 to 6200 does not mean that is the correct range for a 406. Drop both 500. This goes for any cam you look at. Also it will pull quite a bit below that especially with extra lift. Anything you add on the bottom you give up peak power and average power throughout the operating range. The intake/exhaust ratio of the heads calls for a single duration or small split. 108 LSA makes the most power. I tend toward 110 with auto on the street. 112 if your geared high and auto with low rpm convertor. Wider powerband but give up power. Im running 113 lsa and a 6 degree split with AFR but nitrous needs the change. You will notice the majority of aftermarket cams run 110 LSA. Compromise between most power and manners, fuel economy.

 

Quench is .046 that is exactly .005 in the hole and .041 .sbc 400" fel- pro with steam holes.i should have indicated the car is strickly 0 to 80mph not interested in top end power what so ever.3.55 gears with turbo 400 (shift kit) is very nice to drive with 225/R15 goodyear radials.my question is can i play with cam timing to compensate LSA?

 

Machine shop called and will not use my scat rods!! Center of H - beam is not centered in rod and failed in intricate balancing seperate large end small end weight NOT just total weight .going with carillo (sp)?

 

Look at Callies Compstar.

 

LSA is ground into the cam. If you already got it run it.

 

Cam companies have used lift, duration at .050", and LSA as Marketing tools for years. They are reference points but in reality they are meaningless when you want the meat and potatoes of what is needed. What is LSA, the distance between max lift on the intake lobe and max lift on the exahaust lobe.....it also a sum of numbers. 3 + 3 is 6, 2 +4 is 6. Same end result but totally different ways of getting there.

30 years ago the Bowtie head flowed 202CFM at .500" lift and we were excited. The AFR's you have flow 293 at .500". If you do something quicker, fill the cylinder with air and fuel, well it takes less time, Duration.

As 63Mako is pointing out it is the valve events that are critical. Just like when you pull out of driveway in the C3. You have a starting point and stopping point.

 

Thank you Mako ,Straub tech and all our corvette brothers for taking time out to help explain or give examples of cam technology . Straub you must be a good father you have what it takes!

 

I was never blessed to have my own kids but I will take your words with highest degree of a compliment.

 

This...

Carter

 

Times 3!