400 cid for a 79?
Thread Starter
Melting Slicks
Joined: Aug 2003
Posts: 2,135
Likes: 2
From: Dayton Oh
Originally Posted by Easy Mike
The 400 will bolt in, but you're not gaining much. It's externally balanced. My advice would be to keep your 350 and rebuild it.
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
Internally balanced 400 cranks are easy to find, and the block is essentially the same. you're gaining 50 cubes, that's a lot more than "not much." Lots of threads on 400s here, just have to run a search.
Drifting
Joined: Nov 2004
Posts: 1,631
Likes: 293
2020 C3 of the Year Finalist - Modified
"See a video of my externally balanced 400 pulling 550HP @ 6500 RPM in my sig "
heck yeah!....there's nothing wrong with ext balanced motors......get the 400 and enjoy it man!
ryan
heck yeah!....there's nothing wrong with ext balanced motors......get the 400 and enjoy it man!
ryan
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
A properly balanced externally balanced motor will be just a smooth as a internally balanced motor 
That said Scat makes an affordable 3.75 in. internally balanced crank in the 9000 series that work in that 400ci
That said Scat makes an affordable 3.75 in. internally balanced crank in the 9000 series that work in that 400ci
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Melting Slicks
Joined: Dec 2001
Posts: 2,025
Likes: 1
From: Billings MT
Hey Wayne, I thought you were using the Scat 9000 internally balanced crank. I have that crank in my 400 and its sssmooth at 7300rpm.
I would say build the 400, you'll enjoy the power, but you'll need heads that can support the extra 50ci.
I would say build the 400, you'll enjoy the power, but you'll need heads that can support the extra 50ci.
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
No mines the externally balanced version, are you sure yours is internally balanced, I didn't think those cranks came out till after I built mine and long after you put yours in ? I would have used the internally balanced but at the time I didn't think one was available 
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Just a few more details.
Originally Posted by marshrat99
Thanks Mike. About 3 yrs ago, I pulled & store my original, numbers matching engine and built a fairly decent 355. So you're thinking that a mildly built 400 wouldn't be that much of an improvement? IE, I was originally thinking that the 400 block wouldn't be too much of a head ache to get 400+HP which would be about 50+ more than I've currently got.
Well the 400" block will need heads that have coolant passages opened up to match the block - just use head gasket for template. It also helps to restrict the coolant passages in the block's deck - but not manditory. U will need to nail the balancing by selecting the correct crank, flywheel/flexplate, and dampner all to match for either the external balance or internal blance u choose.
So if u gonn'a build a sb then the 400" block will give 50 more inches for close to the same cost. And the larger displacement will handle a larger cam better also. Or u can run a smaller/tammer cam too while still make as good power as larger cammed 350" block.
IMHO the only reason to use a smaller displacement block is cost of finding a rebuildible 400". A good deal on a 400" block may be that it's a bad block - cracked, needs expensive sleeving, excessive core shift.
Good luck.
cardo0
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Originally Posted by marshrat99
Thanks for the info. So for a $150 bucks for a .030 over block, yes or no?
If its a good block thats a great deal. If its a bad block your out only $150 and no labor - that beats pulling a eng at the pick your own boneyard for $200 and having to return it if bad.
Be aware most 400" only bore to .030" but some will go .040" or even 060" (but rare).
For $150 and if your ready to build - yes.
cardo0
