Cam timing 440

Hi all, I have a 440 with an old Iski 505T solid cam (.505 lift Int and Ex 290/254° @ .050) 9.5:1 compression. My question is, what can I expect as reasonable idle vacuum? I am only getting 9-10 inches at the moment regardless of initial timing, is this the most vacuum I can expect from this cam? Also, I have a feeling that the cam is advanced slightly as when the engine is timed to TDC with the timing light (vacuum advance disconnected) then stopped and rotated to TDC, the rotor button is slightly past the No.1 position. Would this also have an effect on the vacuum at idle?

I used one of those Isky grinds on a solid roller cam in the first motor I built for a customer, that cam is a really old school design
I didn't worry about the manifold vacuum and I didn't degree it, I lined up the dots and let the customer have the motor it was a dead dog below 3000 RPM and then it came on like it had a NOS kit on it, I'm going to say it was probably retarded some
On your deal make sure and degree that rascal in Do you know what lobe separation angle it is ground on? If it is ground on a 108 or 106 LSA try installing it 4 to 6 degrees advance, put the intake lobe in at max lift at 101 to 104 degrees after top dead center, that will help the bottom end a bunch
Please let us know what you find out
I ended up using a bunch of different Isky grinds after that one in both street and strip and drag race only cars, all of them where good as long as I degree them in properly The best solid flat tappet grind was the old 616/590 dual patter cam, it was for drag racing only, the LSA was 104 It work really good on the street also with a decent converter installed form 100 to 104 To bad they quit listing it in their catalog It can be bought now as a special grind but other company have better cams now

Thanks Cab, I really appreciate your reply.
You are spot on about how it behaves, struggles to break loose below 3000 then fries the tyres till I back off. It is ground on a 108 LSA and I get what you're saying about advancing it 4 - 6 degrees. I'm happy to give it a shot but I'm a bit concerned as to what that will do for intake vacuum as I'm already struggling to get a decent brake pedal. Do you think advancing the cam will help with this or could it make thing worse?

That's a lot of cam for not a lot of compression- That intake duration isn't really290 at .050 is it? Still I see a vacuum pump in your future, or just switch to manual brakes.

290* Advertised - 254* @ 0.050"

I can't help you on the manifold vacuum as I have never used power assisted brakes on any of my half way fast cars or customer motors that needed decent vacuum
My old 518 C.I. pump gas six pack motor had less than 6.0 inches of vacuum at or below 1000 RPM with the solid roller cam that was 260@.050 on the intake and 266@.050 on the exhaust lobes ground on a 108 LSA installed at 106 intake lobe centers The only reason I know that is trying to get the six pack to idle real low (800 to 850 RPM) in gear to show some of the local "experts" that you could make a Holley carb. idle like that with a little effort
Have you thought of using a electric vacuum pump to help on your brakes

That design is at least 40 years old. That means moderate lift with big duration at 50 lift which means low idle vacuum. I think 9 - 10" vacuum at idle is pretty representative as to what this cam can do.
IMHO advancing the camshaft will increase the idle vacuum. If I'm wrong some angel of mercy will certainly tell me so.

http://iskycams.com/cart/index.php?main_page=product_info&cPath=12_14&products_id=148

The cam is not very aggressive compared to more modern high lift cams. It also has 0.028" lash so the lift is really around 0.480". The highest lift Bullet 0.904 lobe for the same 0.050 duration gives 0.578" gross with 0.008" lash for 0.570 lift.

There's the info, do with what you will. I often wonder whether some of these old lazy grinds might be good starting points for regrinds.

R.

Thanks to everybody for your replies.
Seems everyone I talk to over here just wants to sell me a camshaft and I've grown kinda fond of this old stick.
I'd prefer to try and get some vacuum out of it and bring the power on sooner by advancing it a few degrees.
I'll give it a try and keep you posted.

9-10 honestly sounds pretty good to me for that cam, what are you idling at 1200 RPM? I would expect that cam to pull 6-7 inches at 950 RPM.

Hey, if you're satisfied with the performance, go ahead and use it. Here are some advantages:

1. You already have it
2. The slower ramps should allow running less spring than an ultra modern lobe
3. Should be easier to get valvetrain to last at higher rpm
4. Should not wear as quickly
5. You don't have to worry about flow at 0.700 inch lift, mid-lift flow is more important.

R.