Dskeezy16

iTrader: (1)

Hey everyone Ive got a bored .060 over 283 that somehow ended up in one of my Irocs. Its got flat top pistons, vortec heads, single plane intake manifold, solid lifters, and a 242/248 duration .490 lift cam on a 108 lsa. Im going to be taking it out to the track soon and was just looking to get a ballpark range of what it should rev to. I know it pulls hard to 7500. I didnt build the motor so im not really sure what it was designed to rev to. Thanks for any help.

Twin_Turbo

iTrader: (25)

Keep it under 6500 if you want it to live

AlkyIROC

I highly doubt that. Your tach probably isn't very accurate.

When drag racing, maximum shift rpm is at the top of the HP curve. Where that point is, depends a lot on the cam grind. I high reving engine however is really limited to the internal components. Things like stock rod bolts don't survive long above 6500 rpm.

The camshaft in my engine will make power to 8000 rpm but I only shift at 7400.

five7kid

iTrader: (14)

Neither are we.

Nobody can tell you without knowing the details about what's in it. Whether it pulls hard to 7500, whether you need to shift by 6500 for it to live - can't tell you without knowing what's in it.

Vanilla Ice

You say this then ask random people who also didn't build it?

Galaxie500XL

iTrader: (1)

"Pulls hard to XXXX....." Just before it ventilates the block. Where the power is doesn't really tell you at what point the components inside will fail--just ask anyone who's ever blown an engine.

AlkyIROC

LOL

The original 383 that was in my car when I bought it wasn't too bad. It was an old school 383. Stock 400 crank, rods and rod bolts in a 350 block with stock cast 350 pistons. Solid lift flat tappet camshaft with around 0.550 lift. It had stock smogger heads which really limited power. I was able to get a 14.0 pass with it the first year I raced it. Over the winter, I swapped out the 700R4 transmission for a TH350 with a 3800 stall converter and scrapped the smogger heads for some ported out camel heads with 2.02/1.60 valves.

The first pass in the second year I raced, the car ran 12.0 with crappy 3.27 gears in the diff. Everyone was asking me where I hid the NOS bottle.

I was spinning the engine to 7000 rpm since that's where the camshaft was making power to and managed around an 11.8 second pass as the best run of the year. The very last run of the year however shows what a stock bottom end can do at high rpm.

First guess is that a rod bolt let go at the top end. Damage was extensive. One cylinder didn't even have a piston in it. Block, rods, crank were scrap. Camshaft was broken in at least 2 places and when it tried to exit out the back of the block, it damaged the distributor. Most of the valves were bent but no visible damage to the heads. I yanked the intake and heads off and the rest went into the scrap metal bin at work.

2 years racing that engine with 200 passes and the stock bottom end couldn't take those 7000 rpm shifts. After that I went BBC starting with a 454 and now I'm up to a 588 running 9.0. I still broke a lot of BBC parts over the years but mainly from using cheaper aftermarket stuff. My current engine is worth roughly $20,000 because of the high end parts I now use and it's taking a lot more abuse than what I've previously done.

NoEmissions84TA

iTrader: (1)

He said 283, not 383.
A 283 has a 3.00" stroke and will rev.
Generally add 400 rpm for each 1/4" decrease in stroke.
Most SBC cams are rated for a 350 (3.480 stroke).
So you can add 800 rpm to the cam's stated rpm range.
BUT this is assuming that all the other engine components are up to the task.
Without taking it apart, it's anyone's guess.
If the bottom end parts are rated for high rpm, then it's the valvetrain you will have to keep an eye on, especially the valve springs.

I have a 302 SBC - also 3.00" stroke.
This will be really interesting for me, because I always wanted to try my 302 in my 84 TA.