I'm looking for a new cam for my car and was wondering what you would suggest. I have a
355
sportsman II heads
about 9.75to1 comp
performer rpm cam and intake
headers
2 1/2in exhaust
m-21 4-sp
4.10 posi
750hp carb

i'm just not really happy with the rpm cam.

thanks,
lucky3

It has slow ramps and a pretty wide lobe separation. I should think it might be fine with 10.5+:1 compression. But at 9.75, you;d wnat faster ramps, and a tighter lobe separation to make more cylinder pressure, i.e. POWER.

Would you consider a solid lifter camshaft?? With 4.10s and a 4 speed, you might really like the easy revs of a solid.

How much idle vaccum do you need? Brakes, etc.

I know I do. smile.gif

Originally posted by 427L88:
Would you consider a solid lifter camshaft?? With 4.10s and a 4 speed, you might really like the easy revs of a solid.
OH YEA graemlins/thumbsup.gif

MMMMM...Tasty :D

Originally posted by lucky3:
I'm just not really happy with the rpm cam.
Come on now, say what you Really mean tongue.gif

Its just feels really lazy untill around 4200 or so.

Lack of compression
+
Too much duration
= :( graemlins/sad.gif

= $$ graemlins/angry.gif

Hmmmm,

Sounds ike a job for a 276/284F8......
About 243/251 at .050, .518/.530 valve lift, about 430 REAL BHP at 6400(480-490 on Westech's dyno!).
This is a solid lifter cam. For a hydraulic, the 288/296H8 would work just fine, also. It is 231/239 at .050, .485/.507 valve lift, also 108 LSA. Should make about 390-400 REAL BHP at 5800, rev to 7000.

UDHarold

Well now, thats where I was leading to.

Lucky3, that 276/284 tht Harold mentions is an OUTRAGEOUSLY strong cam. Now, I run it in a 440ci, and its 'just right' 2500-6800, just like the man said.

Thrasher hit the 'system dynamic' on the nose. Too much cam, with wide seat durations, and not enough compression. Get a smaller cam in there.

Before you do, you might want to check how the cam is degreed as well. I believe Edelbrock show that cam with 5 degrees of advance, and it sure sounds like you need that much or more.

Roll the motor over by hand and watch #1 valves as you approach #6TDC ( 180 out). You'll see the exhaust on #1 closing while the intake is opening. Right at #6 TDC the two will pass one another. You wnat to see the exhuast move up past the intake while the intake is moving down, i.e., the intake valve will now be closer to the head surface than the exhaust valve. Thats advanced. If there even, its striaght up, and if the exhaust is still closer to the head, then its retarded.

You definitely want the intake to be .050"-.075" closer to the head surface (lower).

Harolds 276/284 cam will run circles around the EDEL cam, but before you go through the hassle of a change, check your RPM cam's timing. It might be retarded and advancing the cam might help alot.

When you advance the cam BTW, the valves end up being closer to the pistons, so if it was close before, watch out.

Originally posted by 427L88:
.

When you advance the cam BTW, the valves end up being closer to the pistons, so if it was close before, watch out. Close :D
The intake will get closer, the exhaust will get further away ;)
Reason, on overlap the intake is opening & will be further open & the exhaust is closing & will be further closed
Think of it as everything happening sooner in the land of happy cams :D

Curious how that cam will work in a 'small' 355 too.

THNX Mike. You are right. I remember now I had little ex clearance ( about .100 w/o gasket), but that was when the cam was in -8. Never did check it after I put the cam in +7, and remember the builder said the same thing. Man, only 42 and have 'moments'.

Originally posted by 427L88:
Curious how that cam will work in a 'small' 355 too.

THNX Mike. Man, only 42 and have 'moments'. ====
Just wait a few years :D ,,,,,,,,,What was the question :confused:

UD Harold where do i get this these cams from? THanks for the imput guys.

Lucky3,

The 288/296H8 is Lunati's part number 301B3LUN, and the 276/284F8 is a special grind, Lunati 40199 masters 01-UF9-UF8-08-A01. The special solid lifter cam costs 165.44, but the same cam on 110 LSA, Lunati 401A6LUN, also costs 165.44.
Any Lunati/Holley dealer can order them. The part numbers are on the web only right now, but brochures are coming......

UDHarold

THank you