I'm looking to change my cam (separate post on that later) in my 502, since it's running out of breath at the end of the track and is a bit on the small side anyway. What is the general consensus as to what the max rpm is for a 502/502 bottom end with ARP waveloc rod bolts and the assembly balanced by a competent shop. The rods and mains are at the stock clearances (2.5 thous, going from memory). I'm looking to get into the 6500rpm range max and possibly go with a small solid roller (or Hydro roller, if it will make it). Will this 502 survive to 6500 rpm? My thinking is that it shouldn't be a problem, but those are pretty large pistons. It will see about 1000 miles a year with probably 10 to 15 of the miles a 1/4 mile at a time :D .

Thanks in Advance,
Tom

If the assembly was balanced AND INSPECTED by a competent shop - 7K max, 66-6800 shift - will live a long happy life.


IMO

MAT

I agree - 6500 is no problem.

Hydro Roller 502 should be alot of fun. Unless you enjoy adjusting lash, pick a nice hydro roller, cammotion, I don't know if harold ever got lunati to make his HR's, or any whatever that lunati-harold brand was HR's, I only ran one comp HR in my 454, but didn't much care for it.

matt

These motors have lots of good parts in them, with the right cam it should easily go to 7500 if called upon to do so. Whether it will make power over 7000 is probably depends on your cam selection. A matched solid roller or solid flat tappet should wrap up with no problems. Only the hydraulics are valve float prone.

Question, why would you want to spin a 502 that high? THe whole trend and advantage of a prepped 500CI motor is to get into the 600 - 700 HP range without running the motor that high. I think it would be wiser to build the motor to pull down 600-650HP at 5800 - 6000 and maybe run it to 6200 in 1st or 2nd and gear accordingly. If I were to build a durable 500" motor for 7000 RPM ,it is going to need a different radius in the crank, H beam rods, probably a higher pin ht (and floating pins), deeper pan - you get my point.

PS - admit, I don't know much about your setup, so I apologize if this is already figured in.

Put a small-ish solid roller in (250/255@.050) and go racing.

Question, why would you want to spin a 502 that high? THe whole trend and advantage of a prepped 500CI motor is to get into the 600 - 700 HP range without running the motor that high. I think it would be wiser to build the motor to pull down 600-650HP at 5800 - 6000 and maybe run it to 6200 in 1st or 2nd and gear accordingly. If I were to build a durable 500" motor for 7000 RPM ,it is going to need a different radius in the crank, H beam rods, probably a higher pin ht (and floating pins), deeper pan - you get my point.

PS - admit, I don't know much about your setup, so I apologize if this is already figured in. The stock type 502/502 is a street motor and runs 11.9-12.0 in a heavy car. Changing to a big cam really wakes these motors up. If you only want to go 12.0s the 5600 RPM limit is fine but you will get beat by an occasional Mustang and most people put them in to stop that. Six hundred horsepower happens at about 6200 and 700 is 7000 H.P. territory. The parts in these engines will run seven thousand forever as the crank, rods and pistons are all forged. Just for your info., "I" beam rods are stronger by design than "H" beams, ask any engineer. The cranks are easily capable of surviving any rpm within reason. A local guy here ran a 502 with nitrous in a truck for several years and turned it 7500 all the time, so they aren't breakage prone and this truck ran 10.0s @ 130 MPH. The only thing that broke was the rear end.

Kool. Waaaaayyyyy Back, I ran 427's to 7K, but can't say I ever ran any 454 that I had over 6500 - not intentionally anyway. I will attest to the 502 bottum end being beefy, I had the 502HO shortlblock on the stand and went over it. One nice thing about these is the stock JE pistons are lite wt. I have a set of stock bore takeouts home on the shelf, these are much lighter than another set of 427 TRW's that I have, despite being for a larger bore.

Either way - have fun with it.

Guys, Thanks for the replies. Those of you that saw my original post on 1st time at the track can probably see where I'm going with this. For those that did not see that post, here is my situation. I ran an 11.8@113 at the track with a rather small Crane hydro-roller cam in my 502 (226/236 @0.050 with .587/.610 lift). The converter seems to slip more than I anticipated (10%?) and puts my cam waayyy beyond it's useful rpm (5600 or so) and falls flat on it's face at the end of the track. Since my cam is on the small side, and not wanting to leave too much performance on the table, I'm looking to get a cam that can rpm higher. I figured a cam that makes peak power in the 6200 range but will allow an over-rev to at least 6500 before valve float should fit the bill. That was the reason for this post. I'll be posting one of those "can you recommend a cam" posts shortly.

Thanks Again,
Tom

Tom, what lifters and valve springs did you have to use with that cam?

Vince, I used the stock 502/502 lifters with the stock 502/502 valve springs shimmed to bring them up to the specs that Crane recommended for the cam. It ended up with slightly higher pressure at the seat and pretty close to what they recommended at max lift. Crane recommends that the lifters be replaced for anything over .570" lift. I checked the cam with the stock 502/502 lifters and it was fine. not even close to alignment bar disengagement. The lifters still were above the bar on the base circle. I may even be able to go with a little more lift, but I would definitely recheck it.

Tom

Assuming the engine is properly balanced and assembled I wouldn't think it would be a big deal. I've spun my 2 bolt 454 with forged I-Beam rods to 7,400 several times. I had a 4.33 gear under the car for a while and it was running 7,200 through the lights. Never shown any signs of problems. I couldn't find any signs of stress on the main/rod bearings when I freshened the engine either. I have a 4.11 gear back in the car now and I shift at 6,500 and it traps at ~7k. Avoid valve float and detonation and it will probably last a long time at 6,500-7,000.

Thanks Ken, That's what I figured. I just wanted to make sure I was on the right track.

Thanks Again,
Tom

Tom,

Have you considered a spring upgrade? I saw a test where these GM crate BB's lost alot of power over 5500 b/c of the heavy valvetrain. A set up beehives may free up some power for ya.

Vince

Vince, I just wanted to use a spring with specs at what Crane recommended. The beehive springs make me nervous with only one coil. No margine of safety.

Tom