Any Tips for Building SBC 400?

[roadwarriorsvt]

I've got a 84 Jeep with a very mild SBC 350. I'm looking to swap on some 44" Boggers for mud racing and would like a little more displacement under the hood. I'm running full width 60/14 and a WB of 108". Some tips I've found (by doing a search) are:
1) the steam holes that need to be drilled if the aftermarket heads don't have them
2) max bore of .030 over due to the siamese bores
3) can use a 6" rod with custom pistons for a longer stroke.

Any reason not to use an iron head like Dart or World vs. an aluminum head? Any tips on building a 400 cu. in.?
Not really looking to stroke my 350 out to a 383 since the cost of a few more cubes is nominal.

[the1208]

1st thing is ignore everybody who will tell you not to build it they are great engines just remember the steam hole issue thats the biggest thing you need to remember.
2nd Stay away from the 4 bolt main blocks weaker then the 2 bolt.
3rd keep a close eye on what head gasket you use I have heard that some gaskets are not big enough to be on the out side of the bore this may be just a myth but better safe than sorry like I said I have never seen it but when it comes to some of these parts coming from over seas anything is possible.
4th If you can get a copy of John Lingifelter book on modifying a small block Chevy great info on strengthening the block and goes into detail about dispelling the myths of over heating.


Hope this my help GOOD LUCK AND KEEP US POSTED

[One Big Zuk]

I had a 406 long rod (30 over and 350 rods) it was a great motor. Never had any thing go wrong. Its now on the stand for more power there is never too much hp!!! Lol

[mj]

the new dart shp shortblocks are very tough to match
I wouldnt bother with a 400 core now that dart is selling their shortblocks

[FORDTECHGURU]

yeh, make sure you sonic the block, last 400 i did took three blocks in, all were junk, finally the fourth one sonic checked o.k., still had to sleeve one hole.... they are great engines, just getting rare, i would seriously consider a dart short block set up..

[trkklr77]

Originally Posted by One Big Zuk

I had a 406 long rod (30 over and 350 rods) it was a great motor. Never had any thing go wrong. Its now on the stand for more power there is never too much hp!!! Lol

what is a long rod? 350 rods are the same 5.7" that the 400 are.

[1982PrairiePounder]

Throw some AFR 235 heads on it a 292 comp cam, bore .030, stud everything, a RPM air-gap intake and any decent 750 carb shound do, those are my 0.02. With those parts I would guess power to be around 400HP or maybe greater. I totally agree with the1208 SBC 400s are awesome motors, too bad their hard to find now a years. Happy Building.

[roadwarriorsvt]

I'll definitely check in to the Dart shortblocks vs. building one from scratch. Thanks for the tip on sonicing the block. Open to more info. Thanks.

[PYRO]

Did you check out the 400 you told me about?

Here's my 421 SBC that runs on propane with a Pro Shot NOS setup

[mj]

Originally Posted by trkklr77

what is a long rod? 350 rods are the same 5.7" that the 400 are.

400 are a shorter rod then a 350, 5.56" off the top of my head but look it up

[ILF150]

Originally Posted by the1208

1st thing is ignore everybody who will tell you not to build it they are great engines just remember the steam hole issue thats the biggest thing you need to remember.
2nd Stay away from the 4 bolt main blocks weaker then the 2 bolt.
3rd keep a close eye on what head gasket you use I have heard that some gaskets are not big enough to be on the out side of the bore this may be just a myth but better safe than sorry like I said I have never seen it but when it comes to some of these parts coming from over seas anything is possible.
4th If you can get a copy of John Lingifelter book on modifying a small block Chevy great info on strengthening the block and goes into detail about dispelling the myths of over heating.


Hope this my help GOOD LUCK AND KEEP US POSTED

i'm sorry, but i have to know. How is a 4 bolt main block weaker than a 2 bolt main block? Please elaborate.

[TEX]

What are the rules in your class? Typically, any class around here that allows 44's is going to be dominated by 1,000+ HP full-race big-blocks. And none of 'em are going to be running 60/14 bolt combos in their 3,150lb rigs. Do you guys have some sort of "street" class for 44's?

[TEX]

Originally Posted by roadwarriorsvt

2) max bore of .030 over due to the siamese bores

Mine's .040 over

Originally Posted by roadwarriorsvt

3) can use a 6" rod with custom pistons for a longer stroke.

Increasing rod length doesn't change your stroke.

[KWTMECH]

Originally Posted by trkklr77

what is a long rod? 350 rods are the same 5.7" that the 400 are.

OOOOOOOOOOOPPPPPPPPs...


400 rods are 5.565 centerline as opposed to the 350 5.7

[roadwarriorsvt]

Originally Posted by TEX

What are the rules in your class? Typically, any class around here that allows 44's is going to be dominated by 1,000+ HP full-race big-blocks. And none of 'em are going to be running 60/14 bolt combos in their 3,150lb rigs. Do you guys have some sort of "street" class for 44's?

Good question. The classes are determined by mainly by their engine combos, number of cyl., power adder, etc. Tires/lift are not factors. I know the 60/14 is a little heavy for a mud bog, but the rig was originally built for the rocks.

Originally Posted by PYRO

Did you check out the 400 you told me about?

Going with a friend and a mic to check it out this weekend.

[90Ranajo]

Originally Posted by ILF150

i'm sorry, but i have to know. How is a 4 bolt main block weaker than a 2 bolt main block? Please elaborate.

The 400 doesn't have enough meat in the main webs for factory 4 bolt, and given enough power/punishment the web will crack at the outer bolts. If your dead set on a 4 bolt use Milodon splayed caps.

[masonmachines]

Originally Posted by 90Ranajo

The 400 doesn't have enough meat in the main webs for factory 4 bolt, and given enough power/punishment the web will crack at the outer bolts. If your dead set on a 4 bolt use Milodon splayed caps.

The strongest oem 400 block will be a 2 bolt that is converted to 4

[roadwarriorsvt]

Originally Posted by masonmachines

The strongest oem 400 block will be a 2 bolt that is converted to 4

That's what I've learned thru the searching. Not sure I need that much beef for my application though. A stock 2 bolt will work for me.

[IDScout]

Originally Posted by TEX

Mine's .040 over




Increasing rod length doesn't change your stroke.

It does decrease the operating angle of the crank/rod which helps transmit more usable torque and improves longevity. Only worth it in a full on race engine IMO.

[TEX]

Originally Posted by IDScout

It does decrease the operating angle of the crank/rod which helps transmit more usable torque and improves longevity. Only worth it in a full on race engine IMO.

Agreed

[rugburn]

Go bigblock and don't look back

[TEX]

Originally Posted by roadwarriorsvt

Good question. The classes are determined by mainly by their engine combos, number of cyl., power adder, etc. Tires/lift are not factors.

Odd

[ILF150]

Originally Posted by 90Ranajo

The 400 doesn't have enough meat in the main webs for factory 4 bolt, and given enough power/punishment the web will crack at the outer bolts. If your dead set on a 4 bolt use Milodon splayed caps.

Well then, you learn something new every day.

[FORDTECHGURU]

i would term it as decreasing piston thrust, which reduces friction, improving part life...

Originally Posted by IDScout

It does decrease the operating angle of the
crank/rod which helps transmit more usable torque and improves longevity. Only worth it in a full on race engine IMO.

[IDScout]

Originally Posted by FORDTECHGURU

i would term it as decreasing piston thrust, which reduces friction, improving part life...

Yeah, what he said.

Eveyone likes to use the word "thrust"