I have two sidewinders, a "J" and a "K". The J has had some home porting done on it, so I can't compare the ports, and I've never ran the K on anything so I can't offer any info on it performance wise. One thing I will say is that the one you have there is a lot cleaner than mine ..........Jim Kramer

Where are you located? I have a couple sets in NE Iowa. I'll have to dig them out to check for  numbers. $200 pick-up........Jim Kramer

Also to the question of sizing, good question, as there doesn't seem to be much info in the catalog listing as to sizing. Everything is listed as being 3/8. This is a possible issue........Jim Kramer

I am seeing abnormal wear on the balls of my adjusters. I'm gaining considerable valve lash with only a few miles driving and it is coming from the adjuster balls that have worn as much as .030 in less than thirty miles. I replaced the original adjusters ( these arms are the low ratio Iskys ) with new Crane units but that didn't cure the problem. My push rods are 9.157 long Comp items, which are longer than stock, but are still below the spit hole in the rocker arm. The cups are still like new ( no wear ). No apparent wear on the rocker arms themselves, shafts, or anyplace else. The shafts are heavy wall aftermarket with a single oiling hole on the bottom and top of the shaft. Oil pressure is good with a minimum of 20 hot at 1000 rpm immediately rising as the speed increases to about 60 hot at maybe 2500. Valve springs measure about 300/310 at full lift ( about .520 ). I do have a restrictor in the heads, but it's .125 so shouldn't be the problem.

I've used this rocker arm assy. before on my 390 Stock Eliminator motor with no problem. The pushrods are new, with the extra length, to the equation. I'm wondering about the quality of the new Crane adjusters. Has anyone seen a problem with them?   Thank you......Jim Kramer

I have an "H"  6L4 I think. It's still in the motor. It would have to be considered to be a "core". $125. If you are interested I'll try to get it out. It's been setting a long time........Thanks.... Jim Kramer 

It is a little encouraging to think it my improve with use. Right now I have zero miles on it. I too checked freeplay before I ever even started the car, ( mechanical linkage ) and mine was this way from the first push of the peddle. Thanks to all that offered help. If I can somehow figure a solution I'll post it.........Jim Kramer

Yeah, I thought about lengthening that arm after I posted, and I think shortening it would be the answer, and I may try that but it will put the pushrod somewhat out of line. The car since I have had it always had a C4 in it, (raced as  a D/SA car), and I got it as a pile of parts 30 years ago, however it is actually a 390 4spd. car. I never did put the assist spring in and peddle pressure really isn't my problem and I can adjust the point of engagement OK too, Its just that when it does engage it seems like "all of nothing". Its hard to let it out smoothly, It "pops out", or engages very quickly ( with authority ) over the course of maybe one inch of peddle travel..........Jim Kramer