400 blks. are o'k if they are your only options, i've got 2 of them and have had 1/2 doz. in the past. If they are prepared correctly they will handle 600hp for a time. The bottom end and cylinder walls being the weakest points. I personally drill out the steam hole and put pipe plugs in them (keeps them from cracking to the bolt holes)also fill the block to the bottom of the water pump bolts. I've cracked cylinders, broke main webs but have never blown one to pieces. I've had friends that blew the cranks out the bottom and split the steam holes to the bolt holes. This has never happened too me. The best thing about a 400 blk. is that they are getting harder and harder to find, most have gone by the wayside due to racing mishaps.
bottom line is the Dart block is Sooo much better and safer build. I got one of those too.
The 377" in my malibu is a stock block and welded, but i would not recommend doing what i did to keep it alive.

JMO

Zip.

Not this time
 

I know even after i had Howard's splayed caps installed in my 400 i still chickened out using it in a supercharged application. Where do i find these guy's that love these 400 blocks, i'll sell mine .030 over Howard's splayed caps plate hone 750.00. Never assy. after machine work.

Re: Not this time
 

TEAM CHEVELLE FORUM.

Tod74: Thanks if i get rid of it i'll use the money towards a new Dart tall deck to build a 434 with a Vortec ysi supercharger. Can't wait to get started.

Just another note on the GM400. I have some strange friends that drive in left hand circles. When they build a 400, they use the 2 bolt bottom end because the outer (straight pattern) bolt holes weakens the webbing.

Dave

yep.

Ok you guys can call me slow.. But, I just realized that I have a SB 400 in my 4x4 that was just built. It was beefed up some but I dont know how much. So yeah it has power. Anyways, should I worry bout this motor trashing itself or no?

DirkaDirka: I think what they are saying is when you start applying big power something over say 5oo-550 hp i wound'nt look at it as being a long term reliable piece.

I think your ok Dirka, its only in high compression race engines have I seen the problem. Despite the weaknessess of the 400 block it is my favorite engine all around because it is so amazing. I built a 406 with ported Brodix heads and GM Block with a solid lift cam and 10.5 to 1 compression. In a 3200lbs car with a glide and 5000 stall converter it ran 10.60s with a best (in good air) of a 10:55. It ran for 3 seasons every weekend and no problems. Took it out and change compression to 14.5 to 1 and a roller cam, split the cylinder in the 1st pass!!!! Awesome engine tho.

Chris

Ok I was just wondering cuz I didnt want to be out at the sand dunes with it and the motor crap out on me.