408 SBC Recipe?
Thread Starter
Pro
Joined: Feb 2006
Posts: 649
Likes: 10
From: Shelby Twp MI
408 SBC Recipe?
I have dibs on a 400 4-bolt block. Looking for something for fun around town and perhaps the strip a few times. My brother has a 406 so I thought I should get a 408 built just to maintain bragging rights.
Any thoughts on a proven recipe for both bottom and top end? I'd like to start with package deals so all the parts talk to one another and also need it to still run on pump gas. Perhaps an eagle balanced rotating assembly, edelbrock performance package.
Any thoughts on a proven recipe for both bottom and top end? I'd like to start with package deals so all the parts talk to one another and also need it to still run on pump gas. Perhaps an eagle balanced rotating assembly, edelbrock performance package.
Intermediate
Joined: Aug 2006
Posts: 31
Likes: 0
From: Lynn Ma.
I have dibs on a 400 4-bolt block. Looking for something for fun around town and perhaps the strip a few times. My brother has a 406 so I thought I should get a 408 built just to maintain bragging rights.
Any thoughts on a proven recipe for both bottom and top end? I'd like to start with package deals so all the parts talk to one another and also need it to still run on pump gas. Perhaps an eagle balanced rotating assembly, edelbrock performance package.
Any thoughts on a proven recipe for both bottom and top end? I'd like to start with package deals so all the parts talk to one another and also need it to still run on pump gas. Perhaps an eagle balanced rotating assembly, edelbrock performance package.
Russ
NCM Grand Opening Veteran
Joined: Sep 2005
Posts: 20,979
Likes: 384
From: South of giving a damn
St. Jude Donor '11, '17
The 408 is a 350 block, the 406 is the 400, although I'm sure you can find some combo that will come out to 408. I agree w/Gordon, build a 415 or 421.
Le Mans Master
Joined: Oct 2001
Posts: 5,943
Likes: 3
From: Wildwood IL
400's need large intake runners on the heads to make great power. 200cc minimum. With the right cam, ported & worked over stock heads will work for the 400HP range. Most cam co's don't post stats for the 400(Crower does) so for what you want, pick a cam larger than you would for a 350. The RPM range and durration will be a bit lower on the 400.
Make sure the steam holes are drilled in the heads. 750CFM carb minimum. A good (but not necessarily forged) bottom end will be reliable and perform. Steel crank & hyperutectic pistons qualify. Next $ step up would be forged pistons & rods. Or go all out and forge the entire bottom if you can afford it. 10:1 compression with flatop pistons will make good power and still retain drivability. It also will allow for a larger cam choice.
A 400 is a large small block...keep that in mind when choosing components.
Eddie
Make sure the steam holes are drilled in the heads. 750CFM carb minimum. A good (but not necessarily forged) bottom end will be reliable and perform. Steel crank & hyperutectic pistons qualify. Next $ step up would be forged pistons & rods. Or go all out and forge the entire bottom if you can afford it. 10:1 compression with flatop pistons will make good power and still retain drivability. It also will allow for a larger cam choice.
A 400 is a large small block...keep that in mind when choosing components.
Eddie
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Thread Starter
Pro
Joined: Feb 2006
Posts: 649
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From: Shelby Twp MI
421:
Thanks & please keep the advice coming. Here's what I found for sale locally for $900 (OBO) on a 421:
Crank: Part # 40038456000 [Eagle 4340 nitrited]
3.875 Stroke (Eagle) Reground
.020 Rod .040 Main * Internal Balance
Rods: Cat 6000
6" 3-D H-Beam w/8740 A1 Rod Bolts
Rods are New
Pistons: 4.135 Bore Forged JE [Nitrous Dome]
1.062 Compression Height
with support rings
Pistons are used in Good Condition with 2 or 3 passes
All for +.010 400 Small Block (421 C.I.)
Parts are obviously used he said with a couple passes but the pictures look good. What do you guys think about the price? Also, what kind of heads & intake will compliment this set-up?
Crank: Part # 40038456000 [Eagle 4340 nitrited]
3.875 Stroke (Eagle) Reground
.020 Rod .040 Main * Internal Balance
Rods: Cat 6000
6" 3-D H-Beam w/8740 A1 Rod Bolts
Rods are New
Pistons: 4.135 Bore Forged JE [Nitrous Dome]
1.062 Compression Height
with support rings
Pistons are used in Good Condition with 2 or 3 passes
All for +.010 400 Small Block (421 C.I.)
Parts are obviously used he said with a couple passes but the pictures look good. What do you guys think about the price? Also, what kind of heads & intake will compliment this set-up?
Race Director
Joined: Jul 2004
Posts: 12,706
Likes: 329
From: Scottsdale Arizona
Only two comments. I'm not an engine guy and am doing a 400 build, but more for low end street than high HP. I came to the forum for combination advice just like you are. 
The first is that your set up looks like it's for an 010 over block. Unless your used block is essentially new, 010 probably won't clean it up.
The second is that 400 small blocks are externally balanced, though I've read that they can be set up ineranlly balanced. Not sure the crank you've found is appropriate.
Keep the posts coming.
The first is that your set up looks like it's for an 010 over block. Unless your used block is essentially new, 010 probably won't clean it up.
The second is that 400 small blocks are externally balanced, though I've read that they can be set up ineranlly balanced. Not sure the crank you've found is appropriate.
Keep the posts coming.
Pro
Joined: Jun 2005
Posts: 583
Likes: 61
From: USA
well the crank is set up for internally balanced, but that's only as long as you use those rods, rod bearings, pistons, rings, AND balancer & flywheel that was used to balance the crank...
I notice that the balancer & flywheel/flexplate aren't listed in the 421 combo you listed.
"domed pistons"... what kind of compression ratio you looking for, domed might require race gas or octane boost. thought you were looking to use pump gas. you might need to get the specs on that dome and figure the compression ratio.
I notice that the balancer & flywheel/flexplate aren't listed in the 421 combo you listed.
"domed pistons"... what kind of compression ratio you looking for, domed might require race gas or octane boost. thought you were looking to use pump gas. you might need to get the specs on that dome and figure the compression ratio.
