Heres a good read I found on the ez lifters.
"I pulled the new Crower HIPPO's out of my as yet un-fired brand new 540, and replaced them with newer Isky EZX bushing-type roller lifters, since they are more or less the only game in town for that type design. By all accounts that I've come across, these EZX's are much more durable than the needle-types, with respect to the needle/axle problem. So I'll give them a try, even though I really don't like some of their other design aspects. I suppose overall, they can't be any worse than the needle-types, and will hopefully be much better. But, unless those EZX's have better material being used for the rollers, than the basic Redzones, then they also can only last as long as the roller OD's, no matter how well the bushing/axles hold up.
For those who might be interested, here are some things I came across when installing those Isky EZX's in my Dart Big M block with its Comp Cams billet custom solid roller cam:
1. The diameter was larger than Isky told me they would be, thus reducing the lifter to bore clearance to less than I'd really like, but the motor was built already at this point, so honing the bores was not an option. It should be OK, but it is at the minimum, so it does concern me a bit.
2. The pushrod seats were about .040 higher than were the seats in my previous Crower HIPPO's, so I had to get another set of shorter pushrods to maintain the rocker geometry that I had ever so carefully setup with my AFR 335cc CNC heads. So, that cost me even more money, even though Isky told me there would be no change in that regard.
3. Isky's so-called high pressure bushing oiling holes are horizontal holes just above the axle, in the front to back direction, and do not get oil through a passage from the pressurized oil band up above like the Crowers and other lifters do. These Isky bushing/axle oiling holes hang below my lifter bores when on the base circle, where they get no oil at all half the time. Those oil holes will see some oil when they are up in the lifter bores, where there is some oil pressure, though restricted by the amount of lifter to bore clearance available. And they will also see a shot of actual pressurized oil during the relatively brief time (maybe 90* camshaft, give or take), when the holes reach the block's lifter oil galley at max lift. But the way the bushing/axle gets most of its oil, most of the time, is because there are oil holes above the roller, shooting oil onto the OD of the roller. The spinning rollers will throw the oil off and outward just like water off a spinning tire in the rain, but it hits the underside of the lifter body, and then comes back down the sides of the rollers onto the axle, where it can sort of work its way into the actual bushing/axle interface. Overall, I don't like this poor oiling design. Though it does apparently work well enough to get by. But, having the bushing/axle area get consistent fulltime oil directly from the oil band like other lifters do, would be far superior.
4. The lower thrust surface below the large oil band, is really way too short. It doesn't wrap somewhat around the roller like the Crower HIPPO's do, which is a much better design altogether. Some of the Isky's I took apart, showed excessive wear on that shorter thrust surface below that oil band. This is also an inferior design aspect that I don't like.
5. The precision outer diameter surfaces of the lifters were not machined high enough, which I didn't expect to have to look for originally, and so I had 3 lifters stick in their bores. All they had to do was machine about another .100 higher, and it would be no issue. My original Crowers were machined correctly, but the Isky's were not.
6. The one good thing I found with the EZX's is that the large pressurized oil band is lower than they were on my previous Crower HIPPO's, so they don't try to restrict oil flowing through the lifter oil galley like the Crowers would at max lift.
All in all, I was not very happy with my $1,000.00 Isky purchase."