I recently got my hands on this 400 4 bolt main small block. I have eveything ripped off of it except the pistons, what is the best way to remove these froze up pistons from the block.
Also, i need some build ideas for this block before i start dumping money in it. Some feedback would be fantastic!

 

How are the pistons frozen in the block? Are they just not coming out the top, or are they seized?

The 4 bolt 400 blocks have considerably less material in the main webs and are generally considered to be much less desirable than the later 2 bolt blocks

 

If they are siezed in, get a chunk of 2x4, a hammer, and to to town.

 

509 casting 400 block is the best to find. As mentioned above, the 4 bolt mains are weaker than the 2 bolt casting because there's not enough metal in the webbing. A good 2 bolt block with some studs for the mains is the best for a 400 block.

 

To answer you question, as above, a nice peice of 2x4 and a hammer will work well. I usually spray stuff down with wd-40 or Kroil, but even ATF would probably work well. Soak it down and wait a bit, and then hammer the pistons out from the top. If there is a ridge, you are better off reaming it with a ridge reamer before the beating commences. I've also used a ruined hammer handle as well, sometimes helps to squeeze between the cylinders and rods, to hit square on the wrist pin boss. If the suckers don't move, you can hammer them down into the bore a bit, spray again, and then try again out the top. sometimes takes a couple tries to get some lube into the caked on crap in there.

The 4 bolt block will be fine, realistically, but as with most factory blocks, don't expect mega HP for a long life. Make sure you use steam holes in the heads, whatever you do!

 

There may be a ridge at the top of the cylinders that needs to be reamed off before trying to bang out the pistons.

 

Don't sweat the "strongest casting" too much. I had a friend that ran a 4 bolt for 4 seasons in a 1/8 mile drag car. Actually it had been in a circle track prior to that and just freshened up when he traded for it. I bet he had over 250 high 6sec passes with 1 rering/bearing when he ran it. He believed it lived because he kept the rpm's under 6200. Then one day bracket racing he looked over his shoulder and pulled his PG from 2nd to first accidentally and windowed the block with a rod. I have all 3 castings and wouldn't be worried about using any of them. Although a 509 block with milodon splayed caps would be the best.

 

thanks for all of the replies. After taking the block apart and dropping it off at napa , they ran the #'s. The block is a 400, but it has two bolt main caps!They told me it should hold up if i use some ARP studs in the main caps? They are waiting on me to send them some pistons so they can bore .30. If anyone knows of any good pistons i can buy, let me know. I kind of want a kit with fordged pistons, rods and crank. Thanks again for the help!

 

You can free up frozen pistons with stove oil.

Watch your compression ratio on a 400 build. 64cc heads require 18 to 22cc dished pistons (D dish best) . 76cc heads are ok with flat tops.

 

I'd suggest going to the NAPA parts counter and see what they have to offer. A complete rebuild kit with forged pistons is hard to beat, price not bad either, and they get pretty friendly when you buy their stuff along with the machine work.