[pontiacman63383]

I've finally got to the point of getting the drivetrain together on my resto, but I've got a few questions. My main and first question is I have 2 motors that I can rebuild, but they have been setting around for a while apart and have surface rust. I know that which ever I decide to use will need to head to the machine shop to be gone though so tell me this. Is the surface rust a problem that I need to take care of? Is it something the machine shop will have a way of fixing? Next is the blocks themselves, one is a 68 date code and the other is a much later 70's code (don't remember off the top of my head) is one better then the other? I have heard the later year motors were weaker, is this true? Also does anyone know of a st Louis area machine shop that is familiar with Pontiac motors? Last question, as far a rebuilding it goes is there a good kit out there for these motors or am I better off buying the pieces individually? thanks for your help guys.

[steve25]

Most SUFACE rust issues like on the deck surface and in bores is not a problem, but if the main bearings are out and you have rust there that is pretty good buck to hone and or worse bore and then hone out of there!
Also anything more than surface rust or too much taper in the lifter bores will negate the use of that block.

A block from 72 to mid 74 will have a tad thicker cylinder bores and hopefully have less miles than a 68 motor.
Go to the Butler performance or Kaufman performance site a get a rebuild kit from them once you know how much and over bore and what bearing sizes you will need once a machine shop does a check out of the block you use.
Many times in the shop I use to work in I wold get all the rust off a block top to bottom by tossing it in the bead blast cabinet, but not before duct taping off all of the oil passages, even in the lifter bores!

[ponyakr]

I agree that a casting #481988 400 block is a good choice. It has an advantage over the '60's blocks, in that it has all 5 motor mount bolt holes, so that it can be used with either 2 or 3 bolt mounts. It is also a good choice for a stroker build.

But, if you have one of the 400 blocks with a casting number that ends in "557", I wouldn't spend any $ on it. It seems that every time I mention this, somebody comes on and says that the "557" blocks are just fine up to 400hp. And some will say they have raced 'em with more power than that, including spray. But MANY are not that lucky. How lucky are you ?

You asked about kits. I agree that the basic Butler stroker kit would be hard to beat.

http://www.jbp-pontiac.com/products/...s.html#461_467

But if you are just going to do a 400 rebuild, I'd buy the parts separately. You can usually buy SP forged pistons with moly rings for about $400, on Ebay. And you can buy RPM 5140 forged rods, direct, for $276 shipped. Then you can Google up the best prices on all the parts you'll need.

http://www.ebay.com/itm/Speed-Pro-TR...d96c92&vxp=mtr

http://www.racingpartsmaximum.com/sa...tockrod-2.html

Or, if you don't want to deal with a local machine shop, you can buy a shortblock or a complete 400 from Len Williams. He can add forged rods to these 400's for a few bucks extra. Not many shops that I've read about will build a good Pontiac engine that cheap. You have options.

http://lenwilliamsautomachine.com/400_Short_Block.html

http://lenwilliamsautomachine.com/400_Long_Block.html

http://lenwilliamsautomachine.com/455_Short_Block.html

http://lenwilliamsautomachine.com/455_Long_Block.html

[leeklm]

You want options? We got options! If you need help diagnosing strange noises after you fire the new build up for the first time, give me call. I think I have that area covered

[pontiacman63383]

all right, just got back in from the garage. One block is a 69 dated YD motor and had more rust on it then the other since it sat completely apart. The other one Im going to use is the 73 casting #481988 motor as the crank was still bolted in. So they mains are still super shinny! lol. I love the idea of a stroker motor and im a big fan of butler performance already so there's a good change I will just go that route. As far as replacing the block with a Len Williams, Ive rebuild my far share of motors(10 years as a mechanic) so im good on doing it myself. Ive just never dealt with a motor that has been sitting apart for this long. most of the ones ive done was pull out, rebuild and send down the road. Side note. I plan on using a set of 4x head, with the small cc chamber, how do though do with a stroker kit?
leeklm I was reading up on your thread about the noise, did you have any luck finding out what the problem was?

[steve25]

If those 4x heads are not off a motor you know ran good then be sure to get them checked ,as the tend to crack in the exh seat area!