400 small block
#1
Racer
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400 small block
I have a chance to pick up a rebuildable 1970-74 400 small block 4 bolt for $150. I am thinking of building it to put in my 84 in the future. Want some cubes and around 400-450 HP. What kind of bolt up problems will I have with tranny, heads, or accessories?
I have Aluminum L98 113 heads in storage, 700R4 tranny, and the normal 84 accessories.
Any info will help so I know what I am into before I buy!
I have Aluminum L98 113 heads in storage, 700R4 tranny, and the normal 84 accessories.
Any info will help so I know what I am into before I buy!
#2
If you need to overbore it have it sonic checked, make sure you have the correct externally balanced flywheel and flexplate, have the "steam holes" drilled into the heads and head gaskets. You can get really great cranks these days as well as rods and a good main stud kit would be helpful. Remember the engine needs a lot of air to make power so heads are critical. Roller cams really help, you can get away with a lot more duration than a 350" and still idle good. Send me your proposed setup and I will run it across Desktop Dyno. 400 blocks have a bad repputation for blowing head gaskets due to the junk factory cheep snitt gaskets they used, a good fel pro should do wonders.
#7
Racer
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I heard the same thing about 400 4 bolts. Should be strong enough for me and looks like a great deal, as long as I can get everything to bolt up which I am guessing will.
#9
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Originally Posted by vsocks
I have a chance to pick up a rebuildable 1970-74 400 small block 4 bolt for $150.... What kind of bolt up problems will I have with tranny, heads, or accessories?
If you are going to use the 400, external balanced, crank, you'll have to use a 400 damper and flywheel or flexplate. 400 flexplates only come with 168 teeth, which will necessitate a starter change.
Adapting the 113 heads to the Crossfire is a subject not involving the block selection.
RACE ON!!!
#10
Team Owner
Originally Posted by eguyett1985
4-bolts are fine up to about 600hp naturally aspirated
#14
Burning Brakes
a friend of mind builds race engines and he agrees that the 4 bolt 400 is weaker than the 2 bolt version.....it has to do with the cylinder walls being very thin
best thing to do would be find a 2 bolt 400 block and have SPLAYED 4 bolt caps installed
best thing to do would be find a 2 bolt 400 block and have SPLAYED 4 bolt caps installed
#15
There are 3 types of 400ci blocks ! You can find out wich one you have is by the casting number , it`s the number on the back top of the block . Its true that the 2 bolt main is stronger than the 4 bolt because of thin cylinder walls found on the 4 bolt blocks . The Best 400ci block you can have is the casting number #3951509 this is a 2 bolt main block that was made from 74-80 , it is known by the strongest from the other casting numbers because of the metal being stronger .Other 400ci block casting numbers are #330817 wich was made from 72-80 that is a 2 bolt main block and there was the other casting number wich is #5951511 this is the 4 bolt main block that was made from 70-73 later this casting number was made as 2 bolt mains , I think that GM was having problems with the 4 bolt blocks and stoped using them.
The best way to make a 400ci block survive under Hi performance applications is to NOT bore it more than .30 oversize , the maximum safe bore on a 400 block is .40 oversize , it`s also best to use studs instead of head bolts and studs on the mains , this makes it more stronger and make shure before you start throwing all the money into a used block make shure that the block you are using is safe , like it has no cracks and the cylinder walls are nice , the best way is to take it to a reputable bulider and tell him to sonic check it before you start buliding it .
If you search over in this forum you can find pleanty of 400 block setups , some of them even was abused with alot of hi HP parts and none of the members had problems . I think the safe way of buliding a setup in a 400ci block is to build a 406ci , with the right parts it will be a tourqe monster.
Good Luck .
The best way to make a 400ci block survive under Hi performance applications is to NOT bore it more than .30 oversize , the maximum safe bore on a 400 block is .40 oversize , it`s also best to use studs instead of head bolts and studs on the mains , this makes it more stronger and make shure before you start throwing all the money into a used block make shure that the block you are using is safe , like it has no cracks and the cylinder walls are nice , the best way is to take it to a reputable bulider and tell him to sonic check it before you start buliding it .
If you search over in this forum you can find pleanty of 400 block setups , some of them even was abused with alot of hi HP parts and none of the members had problems . I think the safe way of buliding a setup in a 400ci block is to build a 406ci , with the right parts it will be a tourqe monster.
Good Luck .
#16
Le Mans Master
As for correct balancer and such.
A smaller diameter external balanced 400 block (some call it a 383 balancer) can be had and it will drop right in. Or you can go with a good old 8" whatever stock balancer and clearance it on the crossmember.
Flywheel wise: You can buy 400 flywheels for with 153 teeth on them from places like centerforce (276-376$) (700102 I think)
Flexplate (auto tranny): I am not sure what you can use,, but stock 400s did have the 168 tooth version as stated above.
I just bought the centerforce flywheel I listed above for my 383, if you want the brand new SFI certified 400 flexplate PM me, or if you want to know where to get the flywheel cheap, let me know too!
I think CFI is also right on the 168s need a Mini-starter as well. ID85 just had one for sale, don't know if he sold it. Something to check out...
A smaller diameter external balanced 400 block (some call it a 383 balancer) can be had and it will drop right in. Or you can go with a good old 8" whatever stock balancer and clearance it on the crossmember.
Flywheel wise: You can buy 400 flywheels for with 153 teeth on them from places like centerforce (276-376$) (700102 I think)
Flexplate (auto tranny): I am not sure what you can use,, but stock 400s did have the 168 tooth version as stated above.
I just bought the centerforce flywheel I listed above for my 383, if you want the brand new SFI certified 400 flexplate PM me, or if you want to know where to get the flywheel cheap, let me know too!
I think CFI is also right on the 168s need a Mini-starter as well. ID85 just had one for sale, don't know if he sold it. Something to check out...
#17
Le Mans Master
If your going to build up a 400 to make power and be reliable. Spend an extra $500 or so and have the rotating assembly internaly balanced. Then you dont have to bother with counter balanced flywheels.
#18
Race Director
You can buy a 400 CI-153 tooth stock style Flywheel or
or for a ZF you can buy a Single Mass Flywheel for a 400-153 tooth
or you can use your 350 stuff and buy a $20.00 balance plate
or you can balance the internals
I would recommend buying the 400-153 tooth flywheel or balancing the internals which gives you more options
or for a ZF you can buy a Single Mass Flywheel for a 400-153 tooth
or you can use your 350 stuff and buy a $20.00 balance plate
or you can balance the internals
I would recommend buying the 400-153 tooth flywheel or balancing the internals which gives you more options
#19
Racer
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I have an auto trans so no flywheel. I hear the concerns over 4 bolt 400. I am going for 400-500 HP max. Should I pass on the 4 bolt?
It is the 1511 casting number.
It is the 1511 casting number.
#20
Melting Slicks
Originally Posted by vsocks
I have an auto trans so no flywheel. I hear the concerns over 4 bolt 400. I am going for 400-500 HP max. Should I pass on the 4 bolt?
It is the 1511 casting number.
It is the 1511 casting number.