Even if you can live with an aluminum flywheel on the street, how long will it last? 

6 VOLTS/POS. GRD. NW INDIANA

That’s a ‘Yes’ in that narrowing the lobe centerline angle on the camshaft can create some lean and hesitation issues.  That’s simply due to the overlap between the intake and exhaust valves increasing as the lobe centerline decreases and that will have a negative effect on the manifold vacuum at idle.  Intake manifold design becomes a significant player in all of this.  The use of a true dual plane intake is worth as much as a 1½” Hg increase in manifold vacuum versus what you would see with a dual plane intake with a notch in the plenum divider or a single plane intake.  The carburetor signal at idle relies on the manifold vacuum so anything you can do to increase that manifold vacuum will help low end performance.

Lorena, Texas (South of Waco)

Hesitation off idle more/less likely with narrower/wider LSA, generally speaking?

Daniel.  While you do not give the particulars on how much bore and stroke increase you have, it’s difficult to get in trouble with the compression ratio on the Ford Y when using iron heads.  For the math, I used a 0.060” over bore, a 312 crankshaft with the pistons at zero deck, and the E4 camshaft installed straight up (zero advance or retard).  You said a 0.005” mill on the heads, so I used 68cc for the combustion chamber value without any other information to go by.


With these values, I do not see any issues at all with your basic combination.  The engine may see a slight hesitation right off of idle with the camshaft at 108° intake lobe centerline depending upon the carburetor.  Loosening up the lash some more can help with that.  Carb adjustments would include a richer idle circuit and potentially more pump shot from the accelerator pump.

Aluminum or lighter than stock flywheels can make the car difficult to drive in stop and go situations.  Aluminum flywheels work well for something like a circle tracker but not so much for a daily driver and/or a drag car where getting the car moving from a dead stop is more important.  As a general rule, the flywheel weight for a street driven car needs to be at least 1% of the cars weight.  Trucks will use even heavier flywheels to keep the engine from pulling down excessively when engaging the clutch from a complete stop.

Lorena, Texas (South of Waco)

I questioned the use of steel gaskets to find out if there might be a modern sealer or installation method that would put steel gaskets on par with composition gaskets but no such luck.  Quench as mentioned above, is one of the items that would be improved by about -.020" but this engine runs and performs close to perfect. It would have been mice to slightly improve all things considered by changing head gaskets though.  Thanks everyone for your input....



64F100 57FAIRLANE500

"[C]am timed zero"? Do you mean installed straight up, not advanced or retarded? I'm sure you don't mean zero lash. 

6 VOLTS/POS. GRD. NW INDIANA

Although I like to see the quench close to .040, Ted has said that he's seen no difference in engine performance up to .060 quench. If your pistons are .010 below deck, and you use Best head gaskets that have a compressed thickness of .046, your quench will be .056. 

Thanks Ted and Daniel for your input. Retorquing would not be a deal breaker but it sounds like there will be a greater potential for leakage with steel gaskets and that's the kind of information I was looking for.  

64F100 57FAIRLANE500