400 block in a C3... need advice!!!!
Thread Starter
2nd Gear
Joined: Apr 2007
Posts: 2
Likes: 0
400 block in a C3... need advice!!!!
Hey out there, i just picked up a 400 block and am going through all the options... i have a few g's to do it, the motor is out and now i'm weighing my options.
Should i go to a 406? that adds up to $$$ i already have had the block honed with new bearings and rings... is it worth it to scrap it and get new everything including pistons etc...to bore it out?
What Heads should i use?
Any other advice would be great. If there is someone out there with this combo... i'd appreciate the heads up.
Or-- Maybe just get a crate motor? Which one?
The car is a 74 Black on Black, has Guldbrand suspension, custom no seam mako style body and a bitchin custom all leather new chrome interior.
whew!
\
Should i go to a 406? that adds up to $$$ i already have had the block honed with new bearings and rings... is it worth it to scrap it and get new everything including pistons etc...to bore it out?
What Heads should i use?
Any other advice would be great. If there is someone out there with this combo... i'd appreciate the heads up.
Or-- Maybe just get a crate motor? Which one?
The car is a 74 Black on Black, has Guldbrand suspension, custom no seam mako style body and a bitchin custom all leather new chrome interior.
whew!
\
Last edited by JCBand; Apr 8, 2007 at 11:46 PM.
Advanced
Joined: Dec 2006
Posts: 88
Likes: 0
From: Centennial Colorado
hey cool, me and my wife are goint to be putting a 406 in our 76. from what i hear the 400sb can be a real good and strong engine.as far as boring your to a 406 i wouldnt wast the bore if you dont need to save for another rebuild later on. ours was built to make arouund 480hp roler rockers the heads are stock but have been ported and polished bigger valves we still have to get the build sheets so i cant give cam specs but it does have a pretty rad cam im alittle concernd about making vacum for the breaks and lights but we can deal with that when it comes. but good luck i have always liked small blocks for the street.
Instructor
Joined: Feb 2007
Posts: 247
Likes: 0
From: South of GR MI
Don't bore it unless there are scratches. You can go .030, usually .040, but that's it. My 400 block is .030 already and should be bored again. It has deep scratches that won't clean up at 10 more thou, so I have to leave it.
Sounds like you should talk to a local shop and have them suggest some options.
Sounds like you should talk to a local shop and have them suggest some options.
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
Don't bore it unless there are scratches. You can go .030, usually .040, but that's it. My 400 block is .030 already and should be bored again. It has deep scratches that won't clean up at 10 more thou, so I have to leave it.
Sounds like you should talk to a local shop and have them suggest some options.
Sounds like you should talk to a local shop and have them suggest some options.
Race Director
Joined: Oct 2002
Posts: 12,065
Likes: 2
From: Smalltownville Michigan
Cruise-In 5, 6 & 10 Veteran
St. Jude Donor '09
I agree they can but remember, the thiner the walls, the more heat you generate. These cars don't fare too well on the cooling aspect as it is already...
Former Vendor
Joined: Nov 2005
Posts: 683
Likes: 1
From: Mounds View Minnesota
My 434 built in 1998 says differently.....runs about 210 even on 95+ humid days with the smallblock brass radiator.
Just remember to calculate your compression, the extra 50 cubeswill give you a lot more compression!
Oh and get a big cam, again, another 50 cubes!
Keith
Owner of Corvette Engineering AND a Corvette
Instructor
Joined: Feb 2007
Posts: 247
Likes: 0
From: South of GR MI
I doubt it, but I'll have my block sonic'd too see if that's possible the next time it's apart.
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Le Mans Master
Joined: Sep 2001
Posts: 7,739
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From: Unreconstructed, South Carolina
Suggest:
- Have a pro check the 400 block very closely.
- If the block checks good & no cracks around bolt/water holes ... build the 400.
- Bore to +30 as there are VERY FEW piston choices in +20 for 400.
- Use longer than short OE 400 rods ... at least 5.7" ... 6" are great & inexpensive.
- Pick your pistons wisely ... compression/dome volume AND Height.
- Choose a piston and then ZERO-deck the 400 block to that piston ... that's because there are VERY FEW head gasket choices for 400 ... aside from some copper sheet, there are NO thin gaskets for 400 (350 gaskets will NOT last) ... so zero-deck and use a typical 400 gasket to set a good quench height. I suggest this deck approach for 400 but not 350.