So I finally found a great condition 400sbc. Not bored or anything. Came with stock crank. (I dont know if you guys have been looking lately but 400's are super hard for me to find.)

Anyways got a great deal.

Only thing I am unsure about (so far) is that it is a 2 piece seal. And it is externally balanced. I plan on putting this on my zf6 tranny and all the motors those were put on were one piece (assuming). Im still not 100% sure what size Im going with it but as of right now, the plan is 406.. and that is it. Before I had big dreams of big cube strokers... but now I honestly just enjoy being able to drive my cars whenever I want and not having to worry about my rod angles or whatever... Back to the externally balanced issue. If I use the stock crank (I dont plan on it... just for my knowledge) can a zf6 flywheel be balanced for the crank? Also can a zf flywheel (being made for a one piece) work on a 2 piece? Or do I have to buy the Fidenza 2 piece flywheel?

Also the guy I got it from kept insisting that the 509 block (the one I got) is great. Even though its a 2 bolt (not sure if I will splay it or not since Im not trying to get a stupid amount of power) it is one of the best 400 blocks you could get (his words)... Does anyone have anyone have any input on this?

I am sure there is more questions about that but I will start slow. As I am planning this build (or just piece together of random parts) to last the winter.

My current plan is as follows...

New crank. 3.75 400 stroke
6" rods.
9.5:1 pistons (or there about) (bored .030 over)
Ported 113s Heads
Converted LT1 intake


Im considering a zz9 cam... but Im still not learned all the way on the ways of the cam. I get all the basics of how it works and how duration and lift can effect the air flow and stuff (got bored describing ) but Im no cam jedi. Thus CORVETTEFORUM!!

Well I am hoping you guys dont tear up my plans too bad. Im putting it all out on the table for you.
Also keep in mind I am not shooting for super high HP numbers.. Maybe 350-375 at the crank. So let me know what you think!

 

Yes...any flywheel can be balanced to work on the 2 pc RMS crank...but the bolt pattern on the flange of the crank is different too, so you need to also re-drill the dual mass FW with the 2 pc bolt pattern, staggered to the original drilled holes.


See above. You don't HAVE to buy an after market, but expect to spend about $100.00 or more at a machine shop to get your FW balanced and drilled for the older style crank.


Not me. I think ANY 400 block is perfectly sufficient for 350-375 at the crank...and beyond.

I would use more cam.

 

Thanks for the reply! Maybe a suggestion?

Would 230/236 @.050 w/ 110lsa be too big with 113s?

http://www.summitracing.com/parts/cc...make/chevrolet

 

-The 509 block is a good block, you can use the 2 bolt main for the power level you are after.

-I would consider a cam like the ZZ-409 over the ZZ-9 in a 400, but your cam choice will hit your power numbers abd drive great.

-The stock crank will work fine.

-Side note, I have 5 of 400 engines, they are not hard to find where I live. I only need two (One in my vette and one in my Firebird)

 

had three of these back in the day

the 2 bolt crank was considered the best as it eliminated cracking in to the cylinders wall, you could get from a 4 bolt.

i had one i put in a 4 speed p u once. got a balance plate that bolted on with the crank shaft bolts. that was in 82 and all i remember was it came out of Indiana????

just keep it cool. blocks and heads prone to cracking if over heated.

 

Just dont overtorque the head bolts (torqie in small increments) thats where youll usually get cracks from or distortion anyway .They got thin webbing thin decks etc so easy does it. Keep it cool and play hard!

Wouldnt waste money putting splayed mains on a GM block
toss some studs on it if it makes you feel better. Or pin the caps and youll be fine.

509s are good.

 

I put them in my 383, and I'm not sure if it was worth it. The wrist pin is in the oil ring land, and I think because of that my oil consumption is higher than I would like.

 

Ive been second guessing that also.. There seems to be a few cranks that are specific to the 6" rods though. I will do more research.

Big question though is are the 113 heads adaquate (ported) on a 400? Also would a cam with a .520/.520 lift be usable with these heads? I know its not THAT large but I dont know much on the limits of these heads. Also been looking at the cc503 cam, .536/.544..

 

Congrats on the find. I liked the idea of finding a 400 block and doing a 406 but the cons seemed to outweigh the pros when it came to the seasoned blocks. Oddly enough, it's the reverse when you look for 400s in that the two bolts are preferred over the four bolt. I hear (you know how that goes with "hearing" things) the two bolts were good to close to 500 hp if you took it easy on them.

 

We dont know what your heads flow or what valve size etc

Are they ideal probably not will it still run decent probably so.
Youll need to have the springs set up properly to make sure the retainers arent hitting the guide, spring pressure etc. If they need to be taken down some no big deal its quick and cheap.

Youll need to select the right piston to figre a compression that will work with what you got your machinist can do the math on that one.

 

FYI, I have a 400 4-bolt block that I have been using for the last 10 years at close to 600 HP so I am not too concerned with the 2 bolt vs 4 bolt discussion. Either one will work fine at 500 HP.

 

I really wanted one a while back and liked the idea of picking up an old 400 block for a 406 build. I still kind of regret I didn't, I really got hooked on 406s. The general opinion I came across was two bolt, if you could find it. Guess I read too many doom and gloom topics about the block design overall compared to going for a new casting. Sounds like you really did your homework to make yours work worry free as long as you have with that power.

 

The 509 casting has a higher nickle content than some of the other 400 blocks. It's definitely the block to look for as far as factory 400s go. IIRC: The 2 bolt caps are wider spaced than on a 350, and believed to be a little more stable. The 4 bolt (400) caps are rumored to be more prone to cracking, but that might be due to the modified power levels the blocks were subjected to. Two bolt blocks were slightly easier to modify for splayed caps (but now racers use much stronger aftermarket blocks).

I've got a 400 block (509 casting, 2 bolt, bored .020 over) sitting under the bench,,, waiting for a cash infusion........

 

For 400 hp crank the 113's well ported will be fine, just need a big dish piston for low compression with the 58cc chamber. Probably want something like 28cc inverted dome. My 400 uses je inverted domes at 28cc and is 9:1 with 64cc heads. 58 heads will bump that to near 9.5 which is good for low oct gas.

230:236 is fine in a 400. Very mild. You will be fine with that. Should make power to 5500 with well ported heads and matching shorter runner intake
A 230 cam in a 400 is like a 218 ish cam in a 350.

 

With the aftermarket producing 400 blocks (Dart, World Products), there is no real need to search the ends of the world for a good used 400. The newer blocks have thicker decks and better oiling than GMs blocks of the 70's.

 

Plus you can get an shp dart block in oem roller cam configuration with 1 pc rear main seal now to have basically a L98 with 4.125" bore

 

I've been searching for a reasonable 400 sbc around the Houston area and I can tell you the choices are limited....I found a couple that I'm going to call on. Many are unknowns, or damaged. One I came across is $2000 iirc, long block BUT with a dead hole...low compression. There were a couple bare or short blocks in good shape BUT those guys know what they have and want BIG money...one is asking for $6000 for a built short block..

I even had a engine exchange shop tell me they didn't want to sell one outright because they also had a hard time replacing one. They wanted to do an exchange only...

The only issue with the dart and other mfgs is the price. Yessir, they have 400s available and some with lots of goodies already inside...its the asking price that keeps everyone from running out and grabbing up a nice 400 dart engine.

if I can find a used one that's in decent shape, it can be tired, worn out, that's ok.
As long as the block is solid and not TOO much over bore. It gets rebuilt anyway...I think I'll hold out for the "deal". Every once in a while somebody finds one for a few hundred dollars...like other guys have said, it would be a winter project anyway...plenty of time.

 

This is really not a bad deal when you think about all you get with it.
http://www.gmperformancemotor.com/parts/12480159.html

 

I got ahold of a local machinist (just moved here, Northern Tn) and it is quite expensive to port/valve job these heads. Expensive enough to lead me to getting new heads. (Possibly put the 113s on the 85)

It seems to me that the best bang for the buck heads I have found (so far) are the Dart SHP heads. They can easily handle the cam I am interested in and flow well enough that I wont have to worry about them with future mods (if any).

Is there any negative word on these heads? If so what would be a good variance of a fairly inexpensive well performing head? Or if anyone knows someone in the Clarksville (and beyond) area that is less expensive and has high quality machine work.

 

Shp's are fine. Some like the 180's better as they seem to cc closer to 190-195 from what i have seen and flow about same as the 200's so they have decent velocity.

Another brand thats easily 10-20 hp better than shp's are pro-filer and jegs brand heads. Get the 195's for a milder street motor. 210's really do well on a 400. 280xfi and profiler 210's are a 475-500 hp combo easily