Your getting a lot of opinions on this, just remember, some are good and some are crap!! Your combo will work and you should be over 400 rwhp. I drive mine very hard, in the summer 5-6 drag runs a week for over the last 3 years, Just pulled it apart and put new heads on, it looked fine. It is a driver and I drive it. You will be able to build your engine without spending a fortune. Your going to have a hell of a good time driving it, and if you build it right, you should have no problems. Now build it and lets go racing!!!

 

The only stock type block GM rates at 450 horse in thier catalog is the 88962516,The 10066034 four bolt replacement is rated at 350 horse and the 10105123 one peice seal block is rated at 350 horse as well.

 

This is the way I see this kind of discussion. Lets imagine ten people build identical 600 hp 400 sbc motors. One blows up the first year, a couple more blow up within two years, the rest hold together okay. So for seven out of ten people a 600 hp 400 sbc is a great build. All they really needed.
Then you have a guy building 200 engines a year. If he had 20 blowing up the first year and 40 more within 2 years he wouldn't be in business for very long. So what works well for individuals doesn't work for professionals.

 

yeah.. by making people buy top notch parts it takes the risk out of signing your name to it.. in time anything will break. even the best made parts. its not like you are going to be pulling the wheels in a c4 that is still going to be street driven or like you will have the room for points on your license for too many 150+mph jousts. so i would imagine it would last quite a while.

 

Blockman, I think the manufactures under rate the power their blocks will handle. You wouldn't want to over rate them and have a class action lawsuit. I think block failure is really pretty rare. Think of the thousands of F body 2 bolt main cars that have head and cam packages on stock bottom ends, superchargers, turbo's, NOS ect, and made over 500hp. You might hear about the ones that fail, but what about the thousands that don't fail. I don't see aftermarket manufactures saying putting a power adder on your stock bottom end will blow your block apart. I pushed the hell out of a local 95 TA 2 bolt main that had ported LT4 heads, hot cam, Vortech S trim 10 lbs boost, and a 100 shot of NOS. We knew we were pushing the limits big time, and it had a pretty conservitive tune. Well it wasn't the block that failed, it was a piston. We didn't care because a stroker motor was in the future. And when we tore it down, the crank and bearings, and block were fine. We reused the block, and put splayed 4 bolt caps for the next engine, because we stroked it to a 409 with 15 lbs boost and nos, and alot better heads and more cam. I think when pushing stock bottom ends, piston failure is alot more common than block failure. There are alot of guys at our track that use stock blocks that make over 500hp and run for years with out problems. Even my bowtie block is rated pretty low. I don't remember the numbers. But it has been pushing over 800 hp for years with no failures. It seems like for the every one block you hear fail, you don't hear about the thousands that don't fail. I don't see power adder manufactures state that adding a blower, Nos or a turbo will blow your block apart. I think a piston failure would be a much bigger concern, than a rod failure, than a crank failure, then a block failure. Sure blocks have their limits, but they can be pushed past what is advertised just like alot of other parts. Crower sportsman stroker rods are rated to 550 hp, but I have seen them pushed way past 800 hp for years and never fail. A friend had a set in a circle track car that went 7500 rpm all night long for years, and they never broke. I just think you have to take some parts power ratings with a grain of salt.

I am sure I will need my flame suit on after this response! I am sure you will tell me you have seen this and that blocks blow up with 300 hp. And I am sure you are alot smarter than me, so what I have to say probably really means nothing.

 

 

 

We deal with alot of circle track engines and street and strip and I can't remember that we have had a piston issue ever or rod issues, We don't seem to have any block issues but we don't run a 2 bolt where a good 4 bolt should be and if a block is going to be pushed over 425 horse we will go to billet caps and over 500 horse we go to splayed caps or go to an after market block in most cases and this works for us.

I am sure if we used cast or hyper pistons in our builds we would surely see problems as there are guys at the tracks that try these and they do have problems.

I bet we put on splayed caps on at least 5 or 6 two bolt blocks because they don't work in the 375 horse engines and when guys tear them down the bottom of the center caps look like they have been welded on, Probably more of an RPM issue then the power side.

We have 400 blocks running in 450 horse builds and run fine, I talk to Mike Lewis http://www.lewisracingengines.com/ who builds alot of engines last nite has six 400 hundred blocks in his shop that only 2 were good enough to build after being checked out.

Look at this link http://www.camaros.net/forums/showthread.php?t=170780 this guy is not happy with his builder as he lost a cam lobe the caps are moving around on his block and I am pretty sure we will end up fixing this engine for this guy.

(1) We try to use a block that is disigned for the intended HP level

(2) We stay away from cast cranks

(3) We stay away from Hyper pistons

(4) We use quality parts (Example we use P-55 cam cores on our flat tappet engines and good lifters)

(5) Everything is machined and fitted

I agree there seems to be a lot of piston issues out there along with broken cast cranks, broken caps and blocks guys seem to be off on their tune up or not using good enough parts in their builds.

We seem to have a pretty good program that has seemed to be working without any issues so far and we have guys drag alot of broken parts in shop that don"t work and after seeing what they use and what we use their seems to be a big differance.

There also seems to be an awful lot of shorty machine work going on out there that would work for a bone stock engine but if your building a peformance peice its has to be don't right to live and perform.

If I could only base all my info on one engine that has lasted for years

 

From my experience building competition engines I can say this with certainty...if the tune is correct it will live beyond expectations, if the tune is wrong....nothing I can do will make it survive the night...

 

+1,I have built many engines through the years,a sbc motor will take alot,have the block checked by a shop,line bore,etc, since they came out with the new ls series motors I have not messed much with the older ones,heck I have a complete stock 400 sitting on and engine stand,just needs a good home. to the OP put a longer rod in it and a good set of mahle pistons,heads and cam make the diffrence.