All Big Six EFI Cam Recommendation Needed

Relates to all big sixes
I'm in the process of stripping the engine (in the truck) for a cam gear, oil pan, exhaust manifold, a couple other gaskets, and anything else I can refresh while it's in the garage. I might as well make some upgrades while I'm at it. The truck is a 1994 speed density, 100% stock. I've read a lot about cams on here the last few weeks. Not looking for anything crazy just an improvement from idle - 3000, the truck has never seen 3500. I'm not interested in forced induction or tuning.
Can I time it straight up?
How will the factory cam timed straight up perform?
I'm considering having the head refreshed with minor porting, thoughts?
Can I go less than 268 duration without detonation?
What other recommendations do you have?
I do have the cam list. Is the stock cam listed for EFI or carbureted?
What is working for you guys and what is not?
Any thought are appreciated.
Thanks
 

THE FRENCHTOWN FLYER

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Yes, clocking the cam from its current retarded position will give you more torque below 3000 (at the expense of a loss of torque above 3000).
I like head clean up / porting for any build, even stock. Also a 30 degree back cut on the intakes helps.
Advancing the cam and shortening the intake duration will make the engine more susceptible to detonation. Depending on where you live you may have to either retard timing a skosh or switch to a higher octane rating fuel.
Reduce the exhaust backpressure.
EFI and carbed engines use the same cam specs. Part numbers may differ.
Consider the Scorpion 1.73:1 roller rocker arms over the stock 1.6:1
 

pmuller9

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As you may have noticed we do not have a definitive success story on the use of aftermarket cams with the EFI engine.
There are some definite failure stories.
I would do as FTF suggested and look at adding lift to the stock cam with Scorpion roller rockers and improve the port flow.
 
Thank you guys. I had read a lot about people using the Scorpion rockers, and with the stock cam timed straight up sounds like what I’m looking for. I can adjust timing and/or run high test if needed.
Will these rockers fit under the stock valve cover or require anything special to fit, other than new pushrods?
Thanks
 

pmuller9

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In don't know about valve cover clearance.
You may be fine with stock pushrod length because you will be using the stock cam.
You might want to replace them just to get a stronger pushrod with thicker walls.
 

Wesman07

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I’ve ran the numbers with Bruce’s jr head at least a dozen times on a completely stock fuel injected motor. Every time it came out to just over 170hp, which I think we have determined is unsafe for the factory fuel system.

My recommendation is to do one of three following:

Headers
Cam
Hand porting

As FTF always says. A low flow exhaust will go a long way as well.

I would not recommend advancing the cam if you tow or want to run 87 octane.
 
I called Scorpion today and they assured me the 1059 will clear the EFI valve cover. If the cover interferes they will make me a set of endurance rockers to swap.
 

Daves68Mustang200

Active member
Yes, clocking the cam from its current retarded position will give you more torque below 3000 (at the expense of a loss of torque above 3000).
I like head clean up / porting for any build, even stock. Also a 30 degree back cut on the intakes helps.
Advancing the cam and shortening the intake duration will make the engine more susceptible to detonation. Depending on where you live you may have to either retard timing a skosh or switch to a higher octane rating fuel.
Reduce the exhaust backpressure.
EFI and carbed engines use the same cam specs. Part numbers may differ.
Consider the Scorpion 1.73:1 roller rocker arms over the stock 1.6:1
Were all the stock rockers 1.6:1? I thought i had read somewhere that the older carbed heads had 1.73:1 rockers, so did that change with the EFI head?
 

THE FRENCHTOWN FLYER

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I am pretty sure - without actually checking - that there will be sufficient retainer-to-oil seal clearance to accommodate an additional 10% of valve lift - basically an additional .040".
 
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