Questions on new motor! Please Help!

[95 cobra vert]

I have a couple questions i was hoping one of you out there will be able to answer. My dad is a very good mechanic but it not completely familiar with the EFI system. i am still learing so i am little help. Im sure many of you on here have done this so i hope someone can help. My motor blew up so we replaced it. We had a new block(302) machined to .30 over. We got brand new parts for all the internals. He had my heads milled and new valves put in. The engine it self is completly new. All the accesories are the same and so is the wiring. We got my car running a couple nights ago and i have taken it on a couple test drives for a total of about 50 miles. I know that this is a new engine and that it takes time to break in, but it seems like it is majorly lacking in power. I am not taking it above 3500-4000(at most and only a few times) and i am accelerating very smooth and not running the piss out of it, i am really just babying it. Anyways, we have played with the timing quite a bit and tried a test drive each time we reset it. The car has no low end power and even when i get to higher rpms it feels as though it is lugging. We wondered if it was a bad coil so we changed it with the one out of my other cobra and that made no difference. Our next guess it the cap and rotor on the distributor are bad.Now am i just paranoid and this is how all new engines are when you first get them running or did i miss something? Besides for the .30 over, i have twisted wedge heads. equal lenght shorty headers, exhast, 10.5:1 compression, cold air, 4,10 gears and had the engine balanced. It was running much better before the engine went without the .30 over and running only 9:1 compression. Any help is greatly appriciated and sorry about the less than perfect spelling. Thank you very much for any imput!!!

 

[tvguy]

Put a couple of hundred/thousand EASY miles on it. Then take it to a dyno shop for a proper tune. It will probably "wake up" after that.
pacotaco

 

[STAMPEDE3]

Yea, at least give it time for the rings to seat. Drive nice and easy for 500mi and then start to try to get more out of it.

 

[Daz97Roush]

make sure you get a baseline tune. then break in the engine accordingly.
something i saved and still use today...on proper engine break in

.........................you may not be able to set the timing properly once the motor is running, so leave the hold down slightly loose. Fire up the engine and IMMEDIATELY bring the engine to 1500 to 1800 RPM and set it at that level using the idle screw, adjust the distributor as needed. Keep an eye out for leaks and check your gauges often, 60 PSI of oil pressure is the desired amount during engine break in, try to keep engine coolant temperature below 200 degrees. Spot check headers or exhaust manifolds for signs of inaccurate timing. Run the engine this way for a minimum of 15 minutes, stop only if there is a major problem, such as low oil pressure, excessive coolant temperatures or a major fuel leak, minor leaks can be overlooked for now, but keep an eye on their levels.

Now that the camshaft is properly broken in and the car is ready for the road, it is time to seat the rings. During the first 300-500 miles it is important to idle the engine as LITTLE as possible. The best place for motor break in would be on a highway were accelerating and decelerating can be done safely. During the first 300 Miles it is a good idea to bring the car up to 25 MPH, then with the car in high gear accelerate to 55 MPH or so and then decelerate back to 25 MPH, repeat this several times during the first 300 miles (approx. 15-20 times per 100 miles). The reason for doing so is that under acceleration vacuum drops to almost atmospheric pressure and the air fuel mixture becomes rich allowing the rings to wear in, then decelerating allows oil to wash up into the cylinder walls thus lubricating the rings. During the first 500 miles you will want to use a non detergent oil, and keep the RPM's below 4500, also avoid steady RPM cruising, keep your driving varied and refrain from going full throttle and downshifting.

 

[95 cobra vert]

so this is normal for an engine to do for a few hundred/thousand miles? Are they always this way new?