Ok uhcoog1-Stock cranks running to 8500 rpm from your research,first what are they using for rockers???? stock??? what are they shifting at???? rpm wise ,Talking to the bracket racers at Norwalk a few weeks ago who are using the 392 stroker 5.7's thay are setting there rev limits at 8000 and shifting at 7500 BUT not one of them would tell me what they are using for rockers so I took that as they are NOT stock,Maybe Arlington??? Harlandsharp??? btw also talked to the Harland sharp tech guy about the troubles they had snapping the rockers at 7000rpm (did anyone know that??) and they took the needle bearings out and they all come bushed now,BUT wouldn't give me a rev number on the rockers,I 'd like to hear from someone in the real world who is running a 5.7 at what they are pushing this motor to as far as rpm's,I would NEVER give any number on here for a first time builder of this motor unless you can really back those numbers up with REAL world testing,Some guy might go in and set his rev at 8500 and blow up his upper end not knowing,--Thanks Steve
Steve-
Thanks for the post- I'm sure what I said could be misinterpreted. I will be honest and say I haven't done it, and have only spoken with Stanton motors and a few other folks regarding high rpm in these hemi motors. There isn't much info out there on the internet. I believe the drag pak guys shift at 8300-8400 rpm, don't know what they hit the traps at.
For the general reader: IF YOU WANT AN 8,000+ RPM HEMI, call a professional (like Stanton motors- who built the drag pak motors). Or do it yourself and break stuff finding out what it takes.
What I do know:
Rockers- I believe they run stock rockers, as they're limited to them in the drag pak series.
Rest of valvetrain- I don't know for sure, but I'm assuming they're using the tie downs, and I'm sure a number use the sharadon collars. No doubt with upgraded pushrods, with specific lengths, some of which will pick lengths that put the lifter ~.040 to bottoming out. Total lifter travel is around .160", and stock has .055-.060 preload (so ~.100 from bottoming out).
NO STOCK RODS
NO STOCK PISTONS
8 quart drag pak pan filled to 8.5 quarts, and 3 quart accusump to get to 11.5 quarts total.
Single beehive springs with upwards of 150-160 on the seat and 380++ open, or dual at 180+ & 400+. Cam profile makes a big difference. I *think* most switched to a dual when the rules allowed.
Back on the valvetrain- the heads you have determine the springs and valves you can run. Stock valve geometry puts anything over ~.580 lift to not look good on the stock rockers. It would be prudent to adjust your geometry with different valve heights if you have to have the extra lift.
When speaking with PAC springs, FOR MY APPLICATION (road racing), they recommended a single beehive for 7500 rpm, and a dual spring for 8000+ rpm. I'm guessing the cam profile will play in to what is needed, as well as what valves you have, etc. If you ran hollow valves, titanium retainers, a mild cam lobe, then 8000 rpm *might* be possible with single beehives. Once again, this is something i know very little about!!!
If I were building a bracket motor, I'd shift at 6800-7000 and never go through traps above 7500. I'd use a cam with limited lift (~.580-.600), and I'd get the sharadon valvetrain ties and collars. I'd get custom length pushrods that sit ~.040-.050 from bottoming out, and I wouldn't run the most aggressive lobes on my cam.
