I got a 400sb and have no clue where to start with the rebuild. I don't want it to cost a fortune, but I still want some decent power out of her.
The casting# is 330817 and had a hp rating of 180hp.
My goal is 325hp with a very limited budget. I don't want a drag car, just cruise night cool.

Please help me out.

 

This is just some general info, I don't know the 400 well enough to recommend specific brands/part numbers:

I would start with replacing non-performance type stuff like all the seals and oil pump. On a budget buildup, a standard flow oil pump should be used. Use a double roller timing chain to relieve friction.

Definately get a new cam, it's a lot of horsepower per dollar. You'll probably need to get stiffer springs for the higher lift of the new cam which will involve machining bigger spring seats unless you can find standard OD springs that work well with your cam. As a rule of thumb you don't want to exceed 300# of pressure on a flat tappet cam at full lift, 350# if you have a roller. You'll also need to have your heads machined for screwed in studs so your pressed in ones don't get pulled out due to the new cam. Also, you'll need your valve guides cut down to clear the spring retainers. You may also want to home-port your heads, search the board for details. You can also use thinner head gaskets for increased compression.

Full ehxaust, including a high flow cat.

New intake and maybe carb or convert to TPI.

 

I'd get some SLP headers into a Hooker Cat-back or true duals if emissions isn't a problem.

 

Here's an easy combination that will make way more than 325 hp
but be real easy to live with.
400sbc bored .030 over stock deck height
federal mogul flat top hyperetectic pistons
Stock 5.565 or 5.7" (350 rods) This combo should be balanced.
76 cc open chamber heads 2.02 x1.60 valves
"home port job" and drilled for 400steam holes
Crane PowerMax H-278-2 cam and kit
or Crane blue racer #WG-1173
crane 1.5 roller tip stamped steel long slot rockers
edelbrock Performer rpm intake
ALT* Professional Products Typhoon # 52020 intake
750 cfm carb (edelbrock #1407 or holley #3310)
1 5/8" headers
chevy HEI distributor MSD coil and wires.

some of the better 76 cc heads are casting#
920,441,441X 487, 487X You may have one of these already.
Any of the older pre '74 (76cc) heads are usuable with porting...
This motor would give strong performace with 3.23 to 4.10
rear gear and a 1800 to 2600 stall converter with reasonable gas mileage.
compression ratio would be 9.59:1 with 76 cc heads and
flat tops and a stock block, just right for Sunoco 94....

http://www.professional-products.com/
http://www.cranecams.com
http://www.federalmogul.com
http://www.blueracer.cranecams.com/
Here's some Canadian links
http://www.hi-performance.com/
http://www.amotion.com