i found a good running 305 from an 83 caprice for 200 bucks at a yard in springfield to put in the 82 t/a for now at least, to get the car back on the road again after all these years, im going on saturday morning to pick it up,

i was wondering what anyone might recommend as far as cleaning it up internally, since normally ppl arent goo about changing oil very often and most of the time the oil has been black for along time and nasty,

should i just do it the safe way and make several oil changes in a short amount of time,

or should i go with "magic" engine cleaner product

i have sucessfully internalyl cleaned up old engines in the past by making several oil changes in a short period of time but i jut wanted to see if anyone knew anything better- if anything better exists

i hope for the engine to last a year or two until i figure out/find what i want to put in it for the long haul

after i put this engine in the near future the last big step will be the exhaust, i have a stock oval exit y pipe and stock exhaust pipe under the car, and i have a pair of LT headers that im not totally sure will fit the car yet(i posted a thread about them)

thanks

 

The only part that I have never seen clean up is the heat shield under the intake manifold. The cross-over passages are often caked pretty well around the head in the lifter valley as well. Taking the intake off and cleaning up that stuff would be a reasonable effort.

Similar with the pan - just drop it down while the engine is out and scrape/clean it out.

After that, replace one quart of regular petroleum oil with a quart of synthetic - first oil change, all petroleum. 2nd oil change, 4 quarts petroleum, one quart synthetic. 3rd change, 3 qts petroleum, 2 qts synthetic, etc., until it is all synthetic. Use a "real" synthetic, of course, not the faux synthetics out there. I would also use a good crankcase flush such as the product AMSOIL offers (https://www.amsoil.com/storefront/aef.aspx) before draining the oil for the 2nd oil change.

 

How to freshen up a 305 short block:

1. Don't. It's a waste of money.

2. If you must do it anyway, do it by throwing it in the trash, and freshening up a 350 instead. Costs the same, but you get more for the same money.

3. If you haven't already spent your $200 on a 305 short block core, which is worth less than its weight in scrap metal because it still has to be disassembled in order to get the full scrap value, don't. Buy a 350 core instead. Same price for the core, same price to refurb, but you get more in the end.

In case you haven't noticed a recurring theme here, allow me to state it in simple terms: while the cost is the same for either a 305 or a 350, you get 45 more if you spend money on a 350, than if you spend an equal amount of money on a 305. Therefore it is economically unsound to spend money on a 305. Heads, cams, intakes, etc. are one thing; but the part that makes it a 305 or a 350, namely the short block, is quite another.

 

Wile it is out i would change the rear main seal if i was you. After that you can run it for a day or so with marvel mystery oil then change the oil. Worked extreamly well cleaning my motor.

edit: add marvel mystery oil to 5 quarts of regular oil.

 

Obviously, drain the existing oil and change the filter. For the first couple oil changes I'd run an HDEO like Chevron Delo 400 or Mobil Delvac 1300. Those diesel oils have real strong detergent packs. Also, look into AutoRx.

After cleaning, I'd probably just run it on MaxLife, with a decent filter like a Wix.

 

This is not first hand knowledge but something I heard from a old retired mechanic, they used to use Trans Fluid in the oil for a while (Don't remember how long he said, I know it wasn't a long time). Supposedly it cleaned the motor real well, they also sucked it through a manifold vacuum line to clean the top end.
Never tried it, oil and fluid technology is completely different from when he was busting knuckles.

If anyone has done this recently I would like to know how it works or don't work.