[Cliff R]

It is impossible to "gauge" the rpm range of a camshaft in any engine combination from "seat of the pants" testing. Camshafts simply don't cause a situation where an engine hits a given rpm and the power falls off to nothing.

We often see dyno charts where a particular camshaft made peak power at 5200 or 5300rpm's, but is still making PLENTY of power at 5800 or 6000rpm's. One simply can't "feel" a loss of a couple of HP in a narrow rpm range up near the shift point, at least accurately enough to say a cam has the engine "pulling" hard to at least X rpm's, etc.

My own 455 will rip your head slam off to at least 5800rpm's, with no noticable lag or significant power losses anyplace. Even so, on the dyno it made peak hp at 5400rpm's. We shift at 5000rpm's at the track, and only see a few hundreths improvement shifting any higher in the rpm range.

We've installed and tested the Crower 60916 cam, and the 60243 grind. In 400's at 10 to 1 or slightly higher static compression, manual trans (auto with 3000rpm stall), at least 3.73 gears, the 228/234/112 cam is a very, very good choice. Expect to make peak hp around 5500-5600rpm's, and up near 425 hp with unported large valve heads......Cliff

[steve]

Originally Posted by Cliff R

We've installed and tested the Crower 60916 cam, and the 60243 grind. In 400's at 10 to 1 or slightly higher static compression, manual trans (auto with 3000rpm stall), at least 3.73 gears, the 228/234/112 cam is a very, very good choice. Expect to make peak hp around 5500-5600rpm's, and up near 425 hp with unported large valve heads......Cliff

cliff,

how do you think that 60916 will perform with a lower compression ratio ? like 9.0:1 or even 8.0:1 ???

i am dropping the 60916 in an otherwise stock 400 (small intake valve, large exhaust), with a 4 speed and 3.90 rear.

it is only a temporary combo (not concerned about max performance)...just dont want it to be a complete dog...maybe i need to bump the CR on the cheap somehow ???

[Z Code 400]

Originally Posted by steve

"How do you think that 60916 will perform with a lower compression ratio ? like 9.0:1 or even 8.0:1???

Steve,

With lower SCR, you want an early closing intake event to maximize cylinder pressure. One of the nicest low SCR camshafts in a street-driven 400 is my custom .467"/.467" - 270°/276° @ .006" - 220°/226° @ .050" - 111.5° LSA.

Installed on a 104.5° intake centerline, this asymetrical profile features a very early 34.5° ABDC intake closing event and 0° of overlap @ .050" lift.

(That's even earlier than the '068's 37.0° ABDC intake closing event.)

Very nice camshaft in a 8.00:1 to 8.50:1 SCR 350 or 400...Robert

[steve]

is that lift too much for press in studs....

[gjn]

Originally Posted by steve

cliff,

how do you think that 60916 will perform with a lower compression ratio ? like 9.0:1 or even 8.0:1 ???

i am dropping the 60916 in an otherwise stock 400 (small intake valve, large exhaust), with a 4 speed and 3.90 rear.

it is only a temporary combo (not concerned about max performance)...just dont want it to be a complete dog...maybe i need to bump the CR on the cheap somehow ???

I had this cam in a low compression 400 and hated it. It was like a two stroke; zero power down low and then took off like a freight train (seat of the pants) at 2,800 rpms. I couldn't get the tires to break loose with radial T/A's without power braking. My cranking compression was a lowly 135 PSI. I would do as Cliff suggests on compression if you use this cam!

[steve]

Originally Posted by gjn

I had this cam in a low compression 400 and hated it. It was like a two stroke; zero power down low and then took off like a freight train (seat of the pants) at 2,800 rpms. I couldn't get the tires to break loose with radial T/A's without power braking. My cranking compression was a lowly 135 PSI. I would do as Cliff suggests on compression if you use this cam!

but no one has said if 3.90 rear and 4 speed will help ???

[gjn]

Originally Posted by steve

but no one has said if 3.90 rear and 4 speed will help ???

I tried to crutch it with 3.70's and 2,400 stall which did help a little. But, the bottom line is the fact that the cam needs more compression to be optimized. I am sure 3.90's and a 4 speed would help a lot. But, why not run the optimal compression ratio and have it run better?

[steve]

you guys are right....

i am having a little trouble on advice with this build. its hard to convince folks that i am not a little nuts on this.

bone stock 71 400
7J2 heads w/ small intake and press-in studs
i only replaced:
timing gear
cam bearings
cam
oil pump

i only removed 1 main cap to inspect wear
and left the rotating assembly alone.

i dont want to spend a nickle i dont have to because
it is intended only to keep my bird rolling for a summer or two
until i can get my 421 build done SOLID ROLLER with all
the goodies.

that is where i want to put the cash.


i dont want it to be a piece of crap though. i just might roll over
and have the parts machined if i have to.......


sorry to hijack the thread