[Black408]

First off I have a small block 400 4 bolt main bored .40 over stock rods with speed pro hypereutectic pistons rated at 9.08:1 compression with 76cc heads. I have a set of the old double hump heads with the 2.02 valves, screw in studs and a 1.6 ratio roller rockers with springs good to a 525 lift. The crank is standard and has been polished. I doubt that it needs it but I have used ARP bolts through out the engine. I am considering 2 different cams both from lunati. The first is a 489/504 duration is 227/233 @50 and advertised is 268/276 performs from 1800-6200. The second is a 504/525 duration is 233/241 @50 and advertised is 276/284 performs from 2200-6400. I am using a pete jackson gear drive melling high volume oil pump and everything will be toopped off with a edelbrock performer rpm intake and a holley 750 carb. Transmission is a turbo 350 with a 2500 stall and 3:55 gears. Will be in a 69 chevelle street car that I will drive to the track, the car will not be driven daily so that is not an issue. In the future I will install a set of 3:73 gears and maybe a small 100 shot of nitrous. If you guys have any other suggestions as far as cams or anything that you would change please feel free to let me know. I would have went with different connecting rods and pistons however at this time that was all I could afford. Thanks for all the help.

Lee,:thumbsup:

 

[Brettd85]

Check out this, I am planning on this build. I dont know if it will help, maybe just waste your time, worth a try.

http://www.chevyhiperformance.com/techarticles/6113_chevrolet_406_ci_small_block_build/

 

[Tom Mobley]

use the 268, you'll be better off all around. The 276 might be real hard on your valve springs. valve springs don't like being run close to the edge and the 276 has 525 exhaust.

 

[DOUG G]

With either cam and 1.6 rockers it ain't gonna happen. .504 lift with 1.5's would be ok but with 1.6's it's .537 and the .525 is already too much and with the 1.6's puts you at .560. (or was that lift figured with the 1.6's ?)

Now at 9:1 compression those cams are big.
I was at 9.5:1 and ran a Comp 280H (230 @ .050 and .486 lift with 1.5's or .518 with 1.6's) cam in my 406. Stock home ported heades with 1.94/1.6 valves and ran a best of 13.5 @ 101.7 and 2.73 gears, swapped to 3.73's to a spinning 13.2 @ 103 in a 3450# Camaro.

Best of luck.

 

[Black408]

As I mentioned the pistons are rated at 9:1 with 76cc heads. I will be using a set of double hump 350 heads which I believe are a 64cc head this should help with the compression ratio some. The heads are drilled for the steam holes. Very good point about the rockers I will exchange them for a set of 1.5's however doing a spring swap on the heads is not out of the question. As of right now it sounds like I will be going with the 268 cam. I appreciate everyones help.

Lee:thumbsup:

 

[DOUG G]

9:1 with 76's is about 10:1 with 64's. Still slightly low for those 2 cams but do-able.

 

[Junkyard Dawg]

If you guys have any other suggestions as far as cams or anything that you would change please feel free to let me know.

Are the camel humps the only head you're willing to work with? There are better heads out there.

 

[gnicholson]

Duration on the 1st. one is good. Make sure the LCA is 106 deg.

 

[gnicholson]

use a good timing chain instead of the gear drive

 

[Black408]

Are the camel humps the only head you're willing to work with? There are better heads out there.



As of right now they are the only heads my budget will allow, however in a few months a head swap would not be out of the question. What head would you suggest?