Tops out at 5200 RPM's
 

Hey Guys,
Two questions:
I was told that the engine I bought was a 383 stroker engine with a mild cam.
To me, the power isnt there for a stroker motor. Is there anyway to tell without breaking down the entire motor?

Second question:
The max RPM on this current engine is 5200. To me, that seems low, but I could be wrong.

Specs on the motor-
350 block, hei ignition (stock Chevy Dizzy), RPM Airgap intake manifold, long tube headers, holly DP 650, mild cam (seller stated), Turbo 400 tranny, Auburn pozzi rear end, 3.73 gears.
I think thats all the info that may be needed.

Any info/answers are helpful.

Thanks in advance.

Mike

Thats what dyno testing is for. Mild cam don't tell you much. That is a feel good ,,, marketing selling term.

Marketing ='s say what ever will convince a buyer to hand over his money.

If it has a short duration cam the power and rpm is going to be limited.
crappy exhaust system. crappy heads Car is too friggin heavy. Lame gears ='s slow acceleration

A dyno test and or a drag strip test will tell you about the engines power.

You need the MPH and the actual measured weight w driver.

The max RPM on this current engine is 5200. by what determination?

if you want a chassis dyno power number stick it on a chassis dyno.

if you want a road horsepower number run it down the drag strip. MPH weight
If you want a engine gross brake horsepower number remove the engine and test
on a engine dynometer.

you can never have enough. money can buy more power. its that easy.

Well there is no way to tell whats holding it back. And pretty much no part of the crank or other stroker parts is easy to get too once the engine is in the car. There is really no way to tell.

But 5200 rpm makes me think of a few issues. First does it make power up to 5200 or flatten out but still rev higher than 5200 just without power. Many stock cams will flatten out at 5200 and with a stroker the cam will be even more lame. Also if the stock valve springs are used and theynare weak they can just be floating out at 5200 rpm and will never rev past it.

Also the hei modual can cause some rpm limitations. Might want to check and be sure you have a good modual in the hei.

I dont think you have flow issues. Sounds like a stock or rv style cam to me. Does the engine allow you to rev past 5200 and just not make any power. Or is it dead stopped at 5200.

If dead stopping at 5200 it may be electrical. An hei tuneup kit with coil and modual may be in your future. Check the spark plug gap maybe shorten the gap a little on all the plugs and give it another test drive see if it changes anything.

Was this engine for a car that had tpi originally. If so it may just be the stock cam was reused. Tpi cams are tiny and dont rev over 5200 since the tpi manifold cant flow more air than that. Stroking the engine with the same lame cam will make the problem even worse.

Once you have gone over the hei and are sure its right. You may want to use a dial indicator and degree wheel to find out what type of cam is in the engine. But changing the cam would be easier.

Did you get a build sheet with this engine? Should have all the part numbers or at least a stack of receits. If ypu have the part numbers for the stroker kit or pistons and cam that would help sort things out alot.

Also verify the travel on the accelerator cable. I had trouble with my engine flattening out at about 4K RPM and found that I had not adjusted the accelerator cable when I replaced the carburetor. I was not pulling open the secondaries and that is why power went flat.

Bruce

Good point this happend with one of my porsches. I purchased it from a guy said the motor was bad but the throttle just never opened more than a 1/4 of the way.

Fuel flow can also be effecting the high rpm range if the pump is weak.

a couple of things,
first, do the balancer and flexplate/flywheel have counterweights? its not an absolute answer on if its really a 383, but if it doesn't, chances are good that it is not. many will not go to the expense of internal balancing on one.
second, what heads are on it? does it appear to have stock heads? maybe the valve springs were not replaced or not up to the task.

all of the above,even if just partial,they may be compounded
add in the small carb,and not knowing deck height and where the piston
is in the bore?
When I bought a car with an unknown engine,I took it out
and blue printed the engine
many small corrections had to be made