Anyone have experience with a stroker GM two bolt 400 sbc block...?

Question

...for racing. I got two of em, one bored sixty over with no core shift, align bored with steel splayed main caps. I was gonna use the stock crank(10/10 & steel!) with H beam PF steel rods & KB hyperutectic pistons for a 412 ci package. I'm thinking now of a stroker in the range of 427+ ci. Problems seem to center on the small base camshaft & rod bolt clearance which can be accomadated, barely! My question is the durability of the 400 block bored to this tolerance. When a higher compresion like 13:1+ Mahle pistons is considered, FF H beam rods NOS & 8000 RPM my concern is block fatigue. Even if I fill the lower part of the water jackets with block filler a combo like this may well tweak the block & my wallet. I got a hot deal on it as the block was free as well the machine work. Problem is a GM rocket block or after market block will be consideribly stronger, & cam & block clearance problems are gone, plus even bigger ci combos. Cost shoots to the moon also!!! Comments welcomed!

Answer 1

i would be scared to dump a lot of $$$ into a 421/427/454 and try using a stock block. i know that it sucks to drop 2k on a block but in reality its cheap insurance when you have a $1500 rotating assembly. i built a low rpm (6k) 406 to keep it all on the safe side...i dont want to check the connecting rods from the OUTSIDE!!!
also on a stock block start with a 2 bolt and add splayed caps for durability. i wouldnt want a 4 bolt 400 (stock) personally.
sidenote my 406 had rodbolt/cam issues one 1 lobe (5.7" rods). 10 minutes and a dremel tool and it was done. at 4" stroke i would definately order a small base circle....
http://s53.photobucket.com/albums/g54/chevymanrob/?action=view¤t=motorinstall010.jpg

Answer 2

Not the best choice for high RPM's and high compression---2 bolt mains are a definite bad basis for any hi-po motor. The 400 small block with siamese bores just wasn't designed for super modification without a major cash outlay but anything is possible. Pick up a copy of " How to Hot Rod Small Block Chevy's" for some good info on the subject. Link below is for a 454 small block offering---amazing what's out there now.

Answer 3

I believe the block that you are talking about started as a Diesel, hence is cast iron, but I am not too familiar with any of what you mentioned. It wouldn't make too much sense to increase the clearance if you don't know what material your pistons are, because increasing clearance also means your lubricant delivery will have to be much more efficient and your weight will increase. Also if you are using an Iron block is more likely that it will outlast any steel or aluminum block for racing, however using Nitrous Oxide can be a problem if the mixture runs too cool, can crack your block, At 8000 RMP your consern should be your crank not your block if is iron that is, but if is Steel or Aluminum be aware that it will wear fast, and probably will need to machine after a few runs. Also What kind of head are you using?

Answer 4

Big blocks aren't well known for being reliable at high rpm. You could have the block sonic tested to check cylnder wall thickness. That would give you a better idea of what you're working with. You can also convert over to 4 bolt mains. Your wallet is the key factor in making the final decision on what to build.