Couple of Questions

[60dgrzbelow0]

Should I buy new plugs before I get it hot tanked or should the machine shop have them already?

Have a look at this site...

http://www.compnine.com/

This listing has exploding diagrams of vehicles...engines and transmissions and so forth from GM, so you browse the listings by Year/Make/Model and see if you find a match to your block...the TOC (Table Of Contents) on the parts will provide more information about what goes on...and inside..the engine block. If the ones I recommended are correct...then you can order them (or the less expensive steel variety) from www.rockauto.com and leave them with your machinist at the time you drop off the block for a caustic soda boil out cleaning. It might also be a good idea to let them install your cam bearings too, while you are at it.

If you are in doubt about the accuracy of the suggested metric replacements... just take some basic measurements on the edges that are clean around several of the holes holding the old Freeze Plugs with an inside-outside digital micrometer that reads in both SAE and Metric increments... and that should give you the confidence about whether or not the suggested Dorman plugs are the right fit.

Generally... machine shops charge by the individual piece work, so if they do not want too much money and you don't intend to deck and clean bore the cylinders by 0.75 mm (0.030") then let them do the work while they have the block up on their metal table. The galvanized steel variety are cheap (and cheaper) and will work fine if you do not intend on living with the motor for a very long time to come after you build up the block. At the very least ... you should pay them to mike the cylinders to determine any out of round or badly worn cylinders and Magnaflux the block for any cracks or casting irregularities that might keep you from throwing a lot of time and money at a block that will soon fail you if it is not in good shape.

Eventually.. somebody is going to have to get some precise measurements of the holes inside that engine so you can buy the right sized pistons, rings and engine Babbit bearings to go in them or support the rods that hold them. If you have no experience with engine building and are not intent churning through the learning curve necessary to do this part of the work well....then be prepared to pay for the peace of mind that comes from having a knowledgeable machinist do that part of building the Short Block for you... The rest will not be as hard to get right.

[3400-95-Modified]

Make sure you get the right GM plug for the rear of the motor... if your running a stock cam shaft the center of the cam pokes out the back of the last journal and there is a depression in the rear plug to accept that... I think the regrind cams don't have that though so you can run just a flat plug back there.