400 small block
Thread Starter
Racer
Joined: Jan 2008
Posts: 379
Likes: 10
From: N'Awlins
400 small block
Are the heads on a 400 small block unique to that engine only. I've been told that the 400 had small water holes around the cylinders and the others didn't, thus couldn't be used with the 400. I have a block with no heads.
Any other advice anyone can shed about the 400 I would appreciate it. Didn't some have 4-bolt mains? Any outside characteristics to identify them from the other engines?
Any other advice anyone can shed about the 400 I would appreciate it. Didn't some have 4-bolt mains? Any outside characteristics to identify them from the other engines?
Drifting
Joined: Nov 2005
Posts: 1,601
Likes: 4
From: Texas
Yes they have steam holes.. other small block heads can be drilled
for steam holes to work with 400 blocks...
400ci SBC's work best with heads that have 195 to 220cc intake
ports...
215cc Bowtie Vortecs
200 to 220 EQ Cast Iron
215 Canfields
AFR Eliminators
... You can also run a 3.875 or 4.00 inch crank for more
stroke and cubes...3.875 stroke cranks aren't any more expensive
than 3.75 inch (stock 400 size) cranks..
DZAuto (Tom) has alot of time with 400's.
for steam holes to work with 400 blocks...
400ci SBC's work best with heads that have 195 to 220cc intake
ports...
215cc Bowtie Vortecs
200 to 220 EQ Cast Iron
215 Canfields
AFR Eliminators
... You can also run a 3.875 or 4.00 inch crank for more
stroke and cubes...3.875 stroke cranks aren't any more expensive
than 3.75 inch (stock 400 size) cranks..
DZAuto (Tom) has alot of time with 400's.
Burning Brakes
Joined: Oct 2006
Posts: 797
Likes: 11
Are the heads on a 400 small block unique to that engine only. I've been told that the 400 had small water holes around the cylinders and the others didn't, thus couldn't be used with the 400. I have a block with no heads.
Any other advice anyone can shed about the 400 I would appreciate it. Didn't some have 4-bolt mains? Any outside characteristics to identify them from the other engines?
Any other advice anyone can shed about the 400 I would appreciate it. Didn't some have 4-bolt mains? Any outside characteristics to identify them from the other engines?
One notable characteristic to help identify a 400 is three freeze plugs per side. Some have just the extra boss.
The 4 bolt main was available early on but they were actually weaker than the 2 bolt due to thinning of the main web when the outside holes were put in. If you want a 4 bolt use a 2 bolt block and have splayed main caps installed. The 2 bolt version is plenty strong for a 500 hp street thumper.
I would run the stock stroke with the GM factory blocks. The rod to stroke ratio is already bad on a 400 and stroking only makes it worse.
I would suggest a 5.7" rod though to help improve the R/S ratio.
Make sure you drill the steam holes in the heads or order heads with them if available on the heads you choose.
The deck on the 400s is weak because of the huge water passages. have your machine shop tap the water passages and screw in cast iron pipe plugs. After decking use a 400 gasket as a template to drill the 3/8 water passages out. This strengthens the deck considerably. I would use studs on the main caps also just to be safe. I have a 415 with 210 cc heads that I put together 8 years ago and is still a beast. They are great engines.
Last edited by Injected Stingray; May 3, 2008 at 07:40 PM.
Thread Starter
Racer
Joined: Jan 2008
Posts: 379
Likes: 10
From: N'Awlins
thanks for the feedback guys. Although I was a millwright/machinist and taught mechanical maintenance e.g. pumps,valves, turbines... and can rebuild motors (parts changing) I don't know the differences and interchangeability in the internals of engines. So...thanks again and will ask many more questions.
Race Director
Joined: Mar 2001
Posts: 14,619
Likes: 4,671
From: Mustang OK
2026 Corvette of the Year Finalist - Modified
2025 c1 of the Year - Modified Winner
2024 C1 of the Year Finalist - Modified
2023 C1 of the Year Finalist - Modified
2015 C1 of the Year Finalist
Let me know what particular questions you have about the SB400, and I'll try to help.
Briefly, and read carefully:
If you desire to retain a SB engine in your car, you just can't beat a SB400.
If the block that you have is in good, rebuildable condition, it can very easily be built into a killer street-performance engine.
For the most part, the stories about SB400s not being a good choice because of overheating problems, immediately falls into the catagory of old wives tales.
VERY, VERY little in the way of special things has to be done to build a SB400.
Briefly, and read carefully:
If you desire to retain a SB engine in your car, you just can't beat a SB400.
If the block that you have is in good, rebuildable condition, it can very easily be built into a killer street-performance engine.
For the most part, the stories about SB400s not being a good choice because of overheating problems, immediately falls into the catagory of old wives tales.
VERY, VERY little in the way of special things has to be done to build a SB400.
