i have an 87 formula w/ a little 305, and a 700R4 tranny i just picked up a SBC 400 for it it came out of a 79 C30 i havent seen too much on people doing this, and i dont think it's going to be too much of a problem, everything seems to be the same size, even the oil pan, which i was surprised.

but i was wondering if anyone had any tips or tricks, or know of anyproblems i may run into trying to do this, any helpful advice would be greatly appreciated

 

I had an 87 350 formula I put a 406 in, (.030 over 400) that ran 12.20's and got 23 mpg on the highway.... was a blast to drive. use a smaller cam than you think you need... I ran a .214/.224 duration @ .050 and it worked wonderful. I made my own exhaust, but had cheapie headman headers with no air injection. I ran a hypertec chip [yuk] there are WAY better options out there now.... enjoy !!!! gotta have the external balanced flywheel and harmonic balancer unless you choose to buy a crank that's internally balanced...

 

i already have headers on my 305, and supposedly this 400 already has a cam in it (but who knows?, and i'm not opening it just to find out haha) and i am keeping the externally balanced component, but did you have any problems doing the swap?, and did you use the 400 fan? because i'd like to use that one and get rid of this little electronic fan in mine

 

it does have an edelbrock performer on it, and i have a 625 street demon carb to throw on it, any other little mods to make it quicker?

 

oh yeah, I think the oil pan changes -- the dipstick goes on the other side....
headers SHOULD fit....
I kept my dual electric fans -- and all the computer stuff. I would think of changing to the dual fans, and a newer radiator (they are more efficient than the older ones, more fins per inch). you can hook up the fan relays to a mechaincal switch/sending unit in the block that turns them on and off when needed.

quicker? a set of 4.88 rear gears....

I'd think about a 700 or 750 carb if you're going that route, 625 seems a little small for 400 cubes....
I'd also go with a torker II intake or even a victor jr. intake (if you're doing the steeper rear end gears along with)

 

which distributor did you use in the 400, the one for the 400. or the one from the 305?

 

my car was originally a 350 formula, so I used that one because I kept all the computer stuff. You're gonna want a non computer with vacuum and mechanical advance to use with the carb setup.

about 150 or so from all the aftermarket, some less than that.
you will want the small diameter one, so it clears the firewall

 

Make sure you find different heads for that 400. The heads on the stock 400s were terrible, which is why they made such poor horsepower in their stock form.

 

yeah, didn't think about that.... I ran the GM aluminum heads available at the time... But now there's better available and even for less $$ --

I had the machine shop drill the steam holes in the new heads so they matched the block and head gaskets.