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Cam upgrade


710wagon

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...a "180*" cam is smaller than a stock cam.

 

What Is the intended usage of the engine? I would recommend the Delta 280/0.455" grind or (also a Delta sourced grind) the Racer Brown 325R grind. (275*/0.490 lift.)

 

Any smaller cam wouldn't be much, if any, improvement over the stock cam.

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I have an Iskendrian 0.490 laying about and a spare U67 to try it on....

That's what I'm running.

 

New cam = new (or recon) rockers.

Isky set me up with spring rates based on what I told them I wanted to do. Took me awhile to get it dialed in.

I also use a cam oiler.

Oversize valves and ported, stock ex manifold.

I can get to 7000rpms but the alternator(5 so far) screams at me (lifetime warranty :) ) around 6000

I run heavy duty diesel oil.

10 years later, flawless performance!

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I use a full throttle switch to trigger a relay to kill the field coil.

Been running that for years on my Toyota that I hunt mustangs with.

 

Using a relay triggered by the brake light circuit to make the field coil would also work for a track car.

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What's the reason for the switch and dropping the field.. sounds like altenators gets unhappy over 6000rpm.. and I get what your saying hook up wise but mechanically what's happening when you disconnect the field... things are still spinning ? Do you hear anything or just over time burn them up?

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  • 3 weeks later...

Hang, run a significantly larger pulley Or install a switch to drop the field coil when you plan on racing.  That would help take the load off the bearings.

 

Larger pulley is what I've been looking for. I'll give them a look.
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  • 4 weeks later...

More importantly the cams are 270 & 280 duration.  Use the 270 on an otherwise stock motor.  

The 280 would benefit from head porting and a larger carb such as the 38/38 Weber, along with compression of 9.5:1 of higher.  Skip 2 out of 3 and you need the 270 cam to generate higher cylinder pressures.  

 

The .010" lift difference is of little consequence.  Most stock heads have good flow to .500" lift, but you can gain 30%+ cfm with porting.  

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Bull Crap on the no mods necessary unless those cams are ground on a billet which I doubt. If ground on a used cam, the basic circle will decrease in diameter creating more room between the rocker arm and cams basid circle causing you to have to raise the rocker height to adjust the clearance which will move the wipe pattern likely right off the rockers pad eating up your new expensive cam <-- now that's a long sentense 8>) So what I am getting at is cam geometry will need to be checked and probably new thicker lash pads needed and depending on how thick a lash pad needed you may also need new valve spring retainers to hold in place those thicker lash pads. The stock valve springs approach "coil bind" at about 0.460in lift this is directly from the How to Modify OHC bible.

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Isky sells those also. You can cut up a cheap feeler gauge for shims to get it right. Then measure and add up to get the correct lash pad needed

 

I think also, as you get near 0.480" valve lift, the stock springs are close to stacking. Something to research and definitely check for.

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What cam did you get and what upgrades did you do

.490 lift \ 290

Did everything I could and still daily drive it.

That's what I'm running.

New cam = new (or recon) rockers.

Isky set me up with spring rates based on what I told them I wanted to do. Took me awhile to get it dialed in.

I also use a cam oiler.

Oversize valves and ported, stock ex manifold.

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