dan_t

I'm wondering what would be a good compromise on RPM limit of my new build... I'm using an auto and going to keep that at stock shifting points for now ~ 4,700rpm but I want to know what I can hold it too.

Scat 9000 Cast Crank
Scat I Forged I Beam Rods
Claimer Hyper Pistons
Clevite Bearings throughout

The car starts really pulling around 3,000rpm.... I beleive it would make power up to around 6,800rpm but I think that pushing things a little

LT1 Intake, AFR195 Heads, Rollertip Rockers, CC306 - 230/244 .544/.576

Thanks in advance

cwyates4

I think 6800 might be on the high side also, The highest I've revved mine is 6600, but it was still pulling strong-see profile for mods.

You've got to get rid of the stock shift points, you'll barely be getting into the true power of that combo at 4700 rpms.

Rich & Lisa_84

With that cam, I would say 6300 rpm. How well is your rotating assembly balanced?
If it is balanced, it may rev higher, but not make more power.

Pete K

Unless the trans is updated with stronger springs, the clutch packs may centrifically apply above 6300 rpm.

dan_t

that is something that I wish i had addressed when i did the trans rebuild last year Pete. At the time I never thought I'd have gone this far with the motor...

So would people say that 6,000 would be safe then?

dan_t

I also had it balanced once i had done the clearancing... I dont have the spec sheet though

Pete K

I would not lose a wink of sleep at 6000 rpm.

cv67

6800 is wayyy too high, the cam isnt doing anythng up that high .

dan_t

dyno2003 shows peak HP at 6500rpm with a less than 10hp drop at 7000rpm

I think 6,000 is good for me right now though...

Corvette Chris

6k to me seems perfect for that combo.

1985 Corvette

Sounds like you made a good combo! Even if it is just speculation and theory at this point on the rpm ceiling. 7,000 rpm shift point has such a nice sound to it.

Orr89rocz

i got a similar cam i my 383, 230/245 on a 109 lsa with more lift than cc306.

i ran 3 times at the track and it seemed to like shifting near 6400-6500 rpms. rev limiter is set to 6800. i tried 5700 or so, whatever stock trans shift point is now, and then 6000 1stgear/6500 second and then 6500 first/6500 second and that last run would have been the quickest if i didnt spin on launch and the trans would actually have shifted at 6500 instead of holding it to the limiter the 5700 run tho matched the 6000/6500 run ET wise but was a mph short due to a ignition stutter up top. So that is showing broad hp curve from 5500-6500, thats for sure

cc306 in a 383 with good heads should make power to 6500

dan0617

I'd change the governor around to get it to shift automatically at a higher rpm. That's what I did. I have my stock '89 bottom end (CC503 cam and new valvetrain and pushrods) shifting at between 6200 and 6300 automatically. I've seen 6350 on tunerpro. It is still living. I would not be afraid of 6500 or 6600. 6800 is a stretch but it won't die at that, I don't think. I doubt you are making enough power up there to make it worth revving that high, though.

Orr89rocz

motor sure does sound good at 6800 rpms tho

65Z01

Track times are a good way to set up effective WOT shift points if you are correcting for DA changes from run to run, assuming the runs are not in the same outing.

dan_t

the reason I'm not changing the govener at the moment is with stock points I know that I can drive at WOT and giving the motor lots of headroom. I can nail the throttle to over take and I'm not leaning on the engine. It makes good power from 2,600 rpm I would say and is really on it by 3,500.

I think the extra power might have hurried up the death of my slightly noisey wheel bearing though!

Any guesses on the Dana36 life expectancy?

LD85

If you are using Hyd - lifters,,, they have their RPM limit as well.

dan_t

I'm using Comp Cams #853-16 - SB Chevy 265-400 V8 High Energy Retrofit Hydraulic Roller Lifters

I cant find any RPM specific information though

Orr89rocz

you can use LS7 lifters which are good to 7000 they say. so far i've been to 6800 on them a few times and no problems.

Caddy race lifters are next stepup and are good to like 8500 or something. not bad for a 250 dollar lifter setup.

LS7's are best bang for the buck at 100 bucks a set new

dan_t

this is a flat tappet block hence why I'm using retro-fit lifters