[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....

[Z Code 400]

Steve,

I haven't used the press-in studs on a Pontiac yet, but we routinely used .465" lift with SBC press-in studs and 275 lbs open pressure on street engines with no problems. However, It would be very easy to convert your heads to screw-in studs and I think it would be a wise investment.

I have used the stock Pontiac dual springs with .465" lift and experienced good results. B-Man has used stock Pontiac dual springs to around .450" lift in one of his engines.

I buy them new from www.sivalves.com for about three bucks a piece. They average 85-90 lbs. on the seat @ 1.590" and 230-235 lbs. open pressure. They work well up to about .475" lift and they coil bind at about .990" overall. They are fine for 5000 rpm and less.

Perhaps B-Man will chime in with more details...Robert

[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

[68bird400HO]

What is the difference between the Crower 60916 and the 60242. The duration (@ .050), lift, and LSA numbers look indentical??

[steve]

as you would expect the guy at crower said i would have NO problem with that cam @ 8:1 !

[67drake]

Originally Posted by 68bird400HO

What is the difference between the Crower 60916 and the 60242. The duration (@ .050), lift, and LSA numbers look indentical??

I've actually posted this same question,as a few others have also.
The specs are very similar as you said,but the 242 takes a stiffer spring. I guess the 242 has a SLIGHTLY faster ramp than the 916,and according to Ken "Ace" Brewer at Pacific Performance 242 can run with a slightly lower CR than the 916.Thats is the whole reason I decided on it. I also wanted to run the 60916,but milling my "96" heads to the small chamber size needed for 9.5+ CR didn't fly with my engine guy.

[gjn]

Originally Posted by steve

as you would expect the guy at crower said i would have NO problem with that cam @ 8:1 !

Technically, they are right. The motor will run....however, you won't be happy.

[Z Code 400]

Steve,

The Isky 256/262 with .425"/.435" lift would be a perfect 'bolt in' camshaft for your lower compression application. It will work with press-fit studs and stock springs.

I have several people using it and they are thrilled with its performance...Robert

[steve]

thanks robert ! who wants to trade a crower 60916 and lifters for one ?

[Bumper]

Originally Posted by Z Code 400

Steve,

The Isky 256/262 with .425"/.435" lift would be a perfect 'bolt in' camshaft for your lower compression application. It will work with press-fit studs and stock springs.

I have several people using it and they are thrilled with its performance...Robert

DD2000 also loves that cam Robert.

[Z Code 400]

It's a good bolt-in street cam for low SCR engines...Robert

[racerboy]

I am very interested in this topic as I am going to call Ace later today (it's only 6 AM out in CA right now) to order a set of his 5140 Tomahawk rods. I also need a cam for my RA III rebuild. The engine is 400 +.030, zero-decked, and am going to have the machinist put a 10 cc dish in the piston to drop the compression. I want it to run on pump fuel.

I am running #12 heads, an M-20, and a 3.55 rear. I was going to go with the 60916 cam, but now it looks like I might be better off with the 242 cam b/c I am running the lower CR. Does that make sense? I have no power brakes in the car, so vacuum for that purpose is not important.

[67drake]

What is your CR going to be?
I don't know what your heads CC at,but I would guess around 75 cc's.
400,.030" over,10 cc piston relief,.040" gasket,block zero decked,I'm showing around 9.8:1,that would be good for the 60916,might be getting close to detonation with the 60242,but Ken would know more about this than me. I would rather run the 60916 myself.

[67drake]

Figured I'd update my old thread. I just got my engine in and the car on the road.
I went a little different route since I first posted this question,so here is what I ended up running.
71' 400 block zero decked,balanced rotating. CR 9.57:1
96 heads,gasket mached, minor clean up and opening up of bowl area. Milled .060" and running .027" cometic head gaskets
SRS pistons .030" over
4340 I-beam rods
Crower 60242 cam
RobbMc 550 fuel pump
stock intake
stock exhaust logs (for now!), 2 1/2" duals
stock breaker point ignition/coil
Quadrajet,done by me,per Cliffs suggestions
Anyway,I just got back from my first test drive,and this thing rocks!
Still alot more there I'm sure,I spent maybe 30 minutes going over some tweaks on the ignition,carb,timimg,in the driveway,then took it out.
My dyno session was a useless waste of time and $$$,so I never got any WOT pulls on it. So no HP/Torque #'s. I'll be going to the local track as soon as I can,so I guess an ET will have to do! I'll post times when I get there.
Thanks alot for all the help you guys! Cliff,Screaming Chief, Ken "Ace" Brewer,and all the other guys I bugged for info these past few months!
Drake

[grandville455]

Awesome Drake!!.. Bring it to the rock!!!

[95ramairformula]

Great news Drake. Did you use stock pushrods with the heads being milled .060? Did you mill the intake side .060?
Post the track times when you get them.