The legendary Isky 404A Flathead cam

[ken-r-mer]

Saw it in a HotRod feature article. The cam lobes were modified so the lifters were able to be non-rotating and the bottoms slightly curved. Apparently they were able to get the revs up to 7,000. But the cam and lifter life were short lived due to excessive wear. They set a record for a Salt Flats speed at 250 mph for a standard carb vehicle.
But...I was thinking...that was BEFORE the advent of solid rolling lifters. I wonder if anybody ever looked into 1) providing smooth steel sleeves to slip into the block cast lifter sleeves (less sliding resistance) and 2) come up with the duo solid roller lifter setup as seen on today's overhead valve builds, but, for the flathead using that same Isky 404A cam? Solid roller lifters in a flathead. Freeing up friction resistance in the valve train assembly for revs up to 7,000 rpm sounds so...intriguing.

[petehoovie]

Originally Posted by ken-r-mer

Saw it in a HotRod feature article. The cam lobes were modified so the lifters were able to be non-rotating and the bottoms slightly curved. Apparently they were able to get the revs up to 7,000. But the cam and lifter life were short lived due to excessive wear. They set a record for a Salt Flats speed at 250 mph for a standard carb vehicle.
But...I was thinking...that was BEFORE the advent of solid rolling lifters. I wonder if anybody ever looked into 1) providing smooth steel sleeves to slip into the block cast lifter sleeves (less sliding resistance) and 2) come up with the duo solid roller lifter setup as seen on today's overhead valve builds, but, for the flathead using that same Isky 404A cam? Solid roller lifters in a flathead. Freeing up friction resistance in the valve train assembly for revs up to 7,000 rpm sounds so...intriguing.

SEE > https://www.hotrod.com/how-to/instal...athead/photos/

[KiWinUS]

Originally Posted by petehoovie

SEE > https://www.hotrod.com/how-to/instal...athead/photos/

Very nice. I have everything pictured here except the paperwork.

To the OP. Your suggestion have been tried by many I have read. There are now many flathead racers that use roller cams and lifters. I would believe there are probably some in street engines.

[Bored&Stroked]

There are multiple things to consider on using roller lifters on a 404A core:
1) Every 404A cam that I've seen (and I have a few) are made on cast-iron cores - not steel billet cores. Roller lifters should be run on different material than cast-iron cores - though you might get away with it for awhile (given the low spring pressures on our flatheads)

2) The 404A is kind of a copy of an Offy #4 cam (that is where the idea came from) and it uses about a 2" radius on the lifter. Roller lifters have a much smaller radius, so one would lose a lot of mid-lift valve action (acceleration per degree of rotation) that the 404A cam really featured. Losing ramp acceleration would really hurt the performance in my mind. In your mind think about how soon the cam touches the outer portion of a 2" radius lifter, versus about a .750 diameter roller . . . you'll get the point.

3) Adjustable roller lifters are not available from Crower any more. These were our go to option for flathead roller lifters. Now, one can rework another lifter - but this gets mighty expensive. Thinking about a 1" groove lock lifter from Jesel, Morel, etc..

[Ronnieroadster]

ken-r-mer I can answer one of your questions in your second paragraph if anyone ever looked into sleeving the lifter bores for a roller lifter.
The answer is yet I have not only looked into it have actually put many thousands of miles running roller lifters in a flathead block using bronze bushings to reduce the lifter diameter.
The engine in my roadster with original ARDUN heads has been fully rollerized for more than 25 years. The cam however is a steel billet with a custom roller profile.

The Ford flathead engine's we run at Bonneville also run roller lifter's of my own design in the lifter bores of the flathead block no sleeving required. The flathead cam is also a special steel roller profile with a lift that's over 1/2 inch. Each combination is set to run no higher than 6500 for reliability. However the flathead has turned 8000 and survived to run again for many more years.
Ronnieroadster

[ken-r-mer]

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Ever notice a faster acceleration with the bronze bushings due to less friction? I'd think it'd be smoother than the bored casting material.

[KiWinUS]

Originally Posted by ken-r-mer

Ever notice a faster acceleration with the bronze bushings due to less friction? I'd think it'd be smoother than the bored casting material.

Your kidding right?