Well im gonna replace my stock blown lt1 with a new complete lt4 motor.

I know ,from the instruction that i receive, that it need to:

"-Flat tappet hydraulic cams only- Run the engine between 2,000 and 2,500 RPM's, with no-load on the engine for the first 30 minutes. This is critical to break in the camshaft

-Drive the vehicle with varying speeds and loads on the engine for the first 30 miles. Be sure not to use a lot of throttle or high RPM

-Run five or six medium-throttle accelerations to about 3000 RPM (40 to 50 MPH), then letting off in gear and coasting back down to 20 MPH

-Run a couple hard throttle accelerations up to about 5000 RPM (55 to 60 MPH), then letting off in gear and coasting back down to 20 MPH.

-Let engine cool and change the oil and filter and check coolant level, top off if necessary

-Drive the next 500 miles normally, without high RPM's (below 5000 RPM), hard use, or extended periods of high loading

-Change the oil and oil filter again.- Keep an eye on oil level during the first thousand or so miles. Your engine is now ready for many happy cruising miles! "

First: are those instructions good?

Second: i already know that i will need a new pcm tune to make it run perfect but...since i will take care of the break in procedure(no hard driving)can i do the engine break in with the stock lt1 tune?And take it to the dyno tune after...

Thank you

 

I'll let someone else chime in on the break in procedures but in my personal opinion I would atleast do a mail order tune before trying to break it in. They are cheap enough for what you get you might as well do it.

 

For the tune, it mainly depends and how big of a difference in cam you are going to be running in the new motor compared to the old motor...asuming it was tuned before. As long as the BLM's do not bottom or top out, the PCM will still be able to control the fueling to keep the AFR correct so you would be ok. I'd get a scanner to make sure and its always good to have that additional info upon the first fire up of the new motor, hate to burn a valve or something on the initial run. A mail order tune will be a guess IMO without some sort of a scan recording.

 

The new engine is a factory replacement lt4 crate engine:

http://paceperformance.com/index.asp...D&ProdID=43322

350 Cubic inches
10.8: Compression ratio
Factory Horsepower- 330@ 5800
Factory Torque- 340@ 4500
Block, 4 bolt mains, Cast Iron
Cylinder heads- Aluminum 54.4 cc Combustion chamber
2.00" Hollow stem intake valves
1.55" Sodium filled exhaust valves
Special Ovoid High silicone valve springs good for .550" lift
Roller rocker arms
Roller camshaft :
Intake lift- .476"
Exhaust lift- .480"
Intake duration @ .050" - 203 degrees
Exhaust duration @ .050" - 210 degrees
Lobe centerline- 115 degrees
Special roller timing chain set.

It will saty like that with all the bolt on in sig.

 

Not going to install at least a hotcam while you have it out?Could you do me a favor and tell me if the threaded part of the rocker studs are 3/8 or 10mm? I've heard they used to come with 10mm studs now I wonder if they now use the 3/8 studs.

 

Because of the first five words you can skip the first paragragh. And make sure you have a tune that is close as posable for the break in period.

 

So you mean that i can skip this part :

"-Flat tappet hydraulic cams only- Run the engine between 2,000 and 2,500 RPM's, with no-load on the engine for the first 30 minutes. This is critical to break in the camshaft "

Good

 

yes, since that engine has a roller cam