I recently had a very reputable engine shop in New Jersey build me an engine.Its a Chevy 412.Thats a 400 bored .060 over.Now Ive read several threads on 400 about over heating problems but I dont believe that the 400 has over heating problems if steam holes are drilled in the heads and head gaskets.This is a engine being built for some street cruzin.Anyway this what I had built for me.Tell me what you think.

Chevy 400 bored .060 and CK 10 hone,Boil block cam bearing freeze plugs,Cut block square, .025 Deck,Howards cam retro-fit hydraulic roller 234/242@.050,294/302 adv dur..533/.548 lift with 1.5 scorpion roller rockers ,112+4 L/C,10.84.1 Compression ration,Pressed piston on connecting rods,Fly cut pistons ,H616 pistons,210 intake Procomp cnc'd 64 cc aluminum heads with steam holes in heads and gaskets,Holley stealth ram with 30lbs injectors.In front of a 700r4 tranny with corvette internals and 2000 stall.And 3.73 7.5 rear which will be broken soon Im sure.Anyway what do you guys think of this combo for my 89 IROC?

 

Sounds pretty damn good, formidable even!

I assume the steam holes are some type of vent, if so to where does the steam vent, or is it an internal return line to the water jackets? The steam and pressure have to go somewhere.

 

The steam holes are just there for cooling.Alot of people have had issues with 400's over heating but that is because they didnt know that the steam holes needed to be drill into the heads and gaskets.Since there arent many of those blocks left people will try to tell you to get an after market block or just go with a 350 and build it to a 383.But I've been reading about combos for about two years before I got into to this motor.The way I did it was buy a little bit of parts at a time instead of rushing.You can bore 400 .060 over with no problem with a good machinist and a good block.And it will last on the street!It took me about a year and three blocks to get a good one.You'd be surprised there are guys just sitting on these blocks,because they know what they have.I called several Chevy dealerships and one guy told me that if he had one he definitely would not sell it to me.He'd keep it for himself.The problem with this 500 hp 500 ft/lbs of tq motor it will tear the rear up in an 89 IROC.So until I can afford a ford nine inch rear Ill have to take it easy.Know any companies that sell a good rear reasonablly?