[JSchmitz]

[QUOTE=TRADERMIKE 2012;6446001]

Originally Posted by Cliff R

Your logic is flawed some when it comes to getting this engine up and running well. Although you are getting a LOT of good advice here, this is what needs to happen.

Pull the engine, remove the pan and swap the pistons/rods so the notches are toward the front of the block.

The engineers at Pontiac knew more about this than anyone else and they offset them for a reason. I can tell you from accidentally installing a set backwards 40 years ago that EVERYTHING gets better when you put them in the RIGHT DIRECTION. The testing done by a few good folks over the years did NOT include putting 100,000 miles on a 406 SBC in a K-5 Blazer with the first 10,000 miles having the pistons in the block with the offset the WRONG direction. That engine from day one just didn't run right or sound right. It was one of those things with this hobby that you just can't put your finger on and leaves you wondering what was missed during a pretty expensive engine build. I had NO IDEA whatsoever what was wrong with it, so I yanked it back out and after hours of examining everything scattered all over a work bench, I found the issue. The HY-DUTY pistons I bought were all facing the WRONG direction in the block....BINGO!! Nailed it! Back together and FLAWLESS for another 90,000 miles!!!!!!!!!!!!!

Forget this blocking the exhaust crossover thing unless your intake is getting too hot down there in Florida that's it's boiling the fuel out of the carbs at a stoplight. NOTHING good comes from blocking off exhaust crossovers in a street engine aside from you lose thermal efficiency designed into that system by the engineers so you reap the benefits of quicker warm-ups, improved fuel economy, power, and able to effectively burn a leaner mixture thus being able to keep a little extra money in your pocket from the improved MPG's.

As I follow your threads, I simply don't understand this "one step at a time" thing. You have the engine down in the vehicle which is at least 10 times (I'm being conservative here) more difficult than removing it and doing all that work on an engine stand. I get all that, and sometimes due to limited resources we have to work a little harder with things. However, you have discovered a major issue and now the pan needs to come off to remove the rods and pistons. Take a step back, take a deep breath, forget trying to find an easy way out and take the plunge. In the big scheme of things, the end result will be well worth the extra effort.......IMHO and FWIW........[/QUOTE

Mikes reply:

I listened to your advice when building the Th 400 and was successful in that endeavor, prudence says to listen to you now!

you said: "Forget this blocking the exhaust crossover thing unless your intake is getting too hot down there in Florida that's it's boiling the fuel out of the carbs at a stoplight. NOTHING good comes from blocking off exhaust crossovers in a street engine aside from you lose thermal efficiency designed into that system by the engineers so you reap the benefits of quicker warm-ups, improved fuel economy, power, and able to effectively burn a leaner mixture thus being able to keep a little extra money in your pocket from the improved MPG's.

Mikes reply: YES, that is exactly what is happening! I have to run rec-89-90 with no alcohol down here in South Florida, and I have made many changes to the coolant system over the years to keep this particular motor in this vehicle to not vapor lock, so I must keep the crossover block plug in play. However, since the Piston s were installed in backwards is a big deal, then I have no recourse to fix that issue, I am convinced that pulling the Crank and pistons is the only way I am truly going to repair someone's blunder and figure out if there are other issues that I can't determine without going all the way. The way the vehicle is set up currently the motor mounts are disconnected and the Oil pan is accessible. I can disassemble the Crank in the car, the Block will be lighter after pulling the Crank and pistons for me and then if it is necessary to remove the short Block, I will have to get my Engine puller back that I loaned to my brother in NW Florida.

Don't need to pull the crank to flip pistons/rods around (unless I missed that you want to pull the crank for another reason lol). Rods have a direction also. Make sure all are correct this time.