409 Cam choice????

[chevyjason]

Hi, I am building a 409 with performance in mind. It's a 65 truck block, 333 heads with large valves, 2 x 4 manifold, 454 crank. 11.1 compression, four speed trans, 4.11 gears in a 62. I would like to use a solid cam.
I have not been able to find anyone that has any idea how different grinds will work in these engines.
I was thinking of an Isky cam with .590 lift and .300 & .254 duration @ .50
Is this sort of cam just un-driveable on the street, or will it cause clearance troubles with the valve train \ coil bind etc. Very rough guess on H.P???
Any ideas or comments are muchly appericated. Thank you.
Jason

 

[CDNpontiac409guy]

Jason, with that much duration @ .050", you better make sure of your piston to valve clearance... IE, adequate valve relief.
Yes, with stock length valves, watch for coil bind. You'll have approx .560" - .570" lift at the valve, so be sure that your springs won't bind up in that travel. Your installed height will be near 1.750", and you should look for around 140 pounds on the seat... not much more than that. 320-340 open would be lots.

I use to run a Crane mech cam in a re-ringed 425 horse engine... had net lift of .560" / .580" lift at the valve, 256 / 266 dur @ .050", on a 110 C/L.
With a stick and 4.56's, it was FINE


BTW, guys... about cams... Comp Cams has been out of W block cores for about a month. Supposed to get some within the next 10 days or so.

 

[Ronnie Russell]

Aubrey is exactly correct. 254 deg. @ .050 is playing with fire. Dont even think about assembling without checking valve to piston clearance. 235 deg @ .050 and .530 lift would be more driver friendly, unless you are building a race only car. Good luck with your project.

 

[GOSFAST]

Cam Choices

The last "decent" driver we built we used a Comp custom grind. This unit was put into a '62 Impala, 4 speed. It was built as a solid roller setup and was totally "acceptible" to drive on the street, even with
the cam specs below! I don't have the final C.R. numbers available but I believe it was built in at 10.25:1.

With the "new" Comp Cams (and others) mechanical rollers that incorporate "direct" oil pressure to the
"axis" and bearing at the bottom of the lifter we now feel very comfortable using these rollers in
"street" units. The spring pressure's still have to be maintained (checked occasionally), but that's not a major issue.

Anyway, the cam we chose for the above unit was a 252/262 @ .050" with .640"/.622" lift and a 110 L/S
(installed @ 110 C/L). This was also a Ross custom piston deal and standard BBC (3/8 bolt) connecting rods. We wanted the bobweight for balancing to be as "light-weight" as possible within reason. We
"internally" milled the pistons after they came in from Ross. We got 25 grams add'l from them after milling. We used a stock "nylon" timing gear set with a roller button and had no issues.

I can tell you this, we had no piston/valve issues with the pistons, but we did have to "notch" the block in 8 corners to clear the exhaust valves at full lift. We used 11/32" stems on the valves to keep that weight down also. Everyting was topped off with a set of "Blue-Racer" 1.7 x 7/16" roller rockers and a set of our own "custom" built guide plates. We did opt for the 3/8" x .080" wall diameter pushrods but could have used the 5/16" x .080" as well. We ended up with .070"/.070" for clearances. This was
checked with the head gasket but without the lash. The lash was .028"/.030".

We didn't get to dyno this unit, the customer did the assembly and installed it immediately. The car was fairly "quick", but I have no time slips available. Thanks, Gary in N.Y.

P.S. If any of you decide to run the "mechanical" roller setup, you have to occasionally check spring pressure. We feel, through years of testing, that most lifters go bad due to the springs "quitting" first, then causing the lifters to literally "bounce" on the lobes. As I stated above the lifters themselves should see much additional street use due to the "direct" oil pressure. The lifters are the same for the SB's and BB's, only the "links" are different! The "Ford" link bars for the roller lifters make the application work with the '09's. They correct the "lifter-bore" spacing issue.