Well I finally jumped in... first i was looking at building my 305 then i thought id get a 350 but I just happend to come across this 400 block for $100 bucks then I ran into a rotating assembly 5.56 rods .030 over flat top pistons and crank for a good price so i did it. Anyway the block is a 1978 400 virgin bore that needs the #1 sleeved its a 4 bolt main. Im thinkin ill convert to hydraulic roller but cant find the conversion kit anywhere?? Basically heres wut i need info on: drilling heads for steam holes, what heads to use for 10:1 CR (sportsman II, S/R torqers? not AFR's) what the best intake/carb combo that will fit under my stock hood, cam with some good lope, and what will work off my LO3 if anything. Ive read lots of the threads about building a 400 but i need a dumbed down version that adresses the do's and definate DON'T's of a 400 build. I'm gonna shoot for 400hp 450tq or close to it and it probably wont see much strip just once or twice a year maybe. Don't let me screw this up! Anybody's $.02 is worth a million bucks to me! Thanks

 

Roller lifters are "retrofit". Click that choice when searching for cam/lifters. Not sure if you're going to see a "kit" - just pick a cam, lifters, and cam button.

Personally, I think I'd spend the money elsewhere and just get a flat tappet cam. Comp XE274 comes to mind. I can't say I'm much into "lope", as it usually means a compromise of low-RPM torque resulting in less area under the curve. With 400 cubes, the XE274 would sound very authoritative.

72cc Sportsman II's would be a good choice. The data sheet that comes with them will have instructions regarding drilling the steam holes.

Performer RPM would be a good manifold choice. Holley 750 DP carb, good exhaust, that combo would do 400 HP easily.

 

exhaust wise if i got long tubes and ran duals back to behind the trans then went into a 3" single (flowmaster single in dual out) so i could atleast save the back 1/3 of my exhaust would that work or would it be a nasty restriction?

edit: and what benifits does these cams with the 4 and 7 firing order swapped have? i keep finding them everywhere

 

If you're going to go to a single 3", you might as well stick with shorties. With a 400 & Sportsman II's, you'd want 1-7/8" primaries, the only choice left these days is Dyno Don's (search on the Exhaust forum).

From what I've been able to gather, the 4-7 swap works in totally tweaked-out combos. You aren't going to see any benefit.

 

mayb ill just redo the whole thing then... how bout like my oil pan, pump, water pump and that stuff?

 

You'll want to use the 400 oil pan. A new oil pump is cheap insurance. If you stick with the serpentine set-up (probably a good idea), you'll want to use a water pump for your original application.

 

Look at ARP bolts for the mains and heads.

Get the part number on the pistons and do the math for your compression ratio
http://kb-silvolite.com/calc.php?action=comp
I think 72cc heads like Five7 mentioned would work good, but double check to be exact.
Hint - deck height should be checked and adjusted as necessary.

Toss around the idea of doing a shortfill on that block - the 400cid 4bolt blocks are supposed to have relatively weak main web areas. A shortfill could help you out there. Do that before boring/honing the block.

 

ive never heard of a shortfill. what does it entail? i searched it and couldnt find much. is it costly? I havnt got the rotating assembly yet so i cant look at it however i know they're flat top pistons and have the valve reliefs so im thinking theyre -5cc so if i go with a pretty decent head gasket thickness i should be able to get 10:1 or a little under. thanks for the link. what kind of red line might i be looking at with the 5.56 rods?

 

The shortfall entails just as Sonix said, the main's webs are weaker then a
2-bolt main 400. If those fail ur motor will most likely be toast. According to FordMuscle.com compression calculator you'ld end up with 10.43:1compression with 72cc heads and .051" gasket/deck volume. As for the redline for 5.56" rods i'ld guestimate them around 5,500rpm-6,000rpm in stock form.

 

shortfIll not shortfAll and i was using the .071 thickness gaskets with the 4.2 bore in the calculator sonix provided it gave me about 9.9:1 the casting is 3951511 i just found out btw.

 

4.2" bore and .071" gaskets????? Where the heck did you get those numbers??
Oh, gasket bore ok... No no, .071" is ridiculous. .040" MAX.

A shortfill is basically filling the water jackets with concrete. That's the idea. You just fill it...a short amount. Just up to the bottom of the freeze plugs. You can buy "hardblok" from Moroso I think, price it out. It strengthens up the bottom end.

Do you have factory 5.56" rods? I'd get aftermarket ones if you can. And/or get ARP bolts for the rods. Single most important mod there.
I wouldn't spool it up higher than 6000RPM, you won't need to anyway.

 

i just searched summit and found this
http://store.summitracing.com/partde...1&autoview=sku

What will happen with a .071 gasket?? If i cant get over .040 for the gasket Im not sure ill have the compression I want what else could I do to get the compression down besides buyin 76cc heads which i dont want to do because i really like those sportsman II's. Im not mixin race fuel.

The rotating assembly im gettin is stock 400 crank .010 under, stock rods and .030 over pistons $350. That isnt actually final yet so should I hold off and try to find 5.7 rods with dished pistons or take that deal for the crank and only use the crank? I really wanna do this right so im open to any and all criticisim. thanks

 

You don't just stack the biggest gasket you can find on there. Gaskets are not a compression tuning tool! At least not that thick.

Here's my calculation for your compression. Why do you think you need race gas? I think you're doing it wrong.

Hint (again!) - deck height, do some research and find out what that means to YOU. Ie - piston compression height, stock deck height and quench. Look those terms up.

I would recommend an aftermarket rotating assembly with hyper pistons and 5.7" rods-ARP bolts, and 12cc dished pistons or thereabouts. They run about $600 or so i'd guess. Get the block zero decked. Run a .040" gasket.
This would make exactly .040" quench and would work GREAT.


This option would cost $600 for the kit, $150 to deck - call it $750 vs the $350 you were planning on spending. The upside is a much nicer running engine with perfect quench and higher CR, plus aftermarket rods and crank for more reliability. That's $400 well spent in my book.

 

Agreed, the problem with trying to control CR with gasket thickness is you destroy the quench effect. You might lower the compression ratio, but in the process increase the propensity to ping because of the lack of quench. Pinging low compression engines are very frustrating.

The right way to go about it is to establish the quench, then pick the piston dish and head chamber volume to finalize the CR.

 

ok ive done some searches and i think ill go with an aftermarket setup for the rotating assembly that way i can custom taylor this and have a good cr and quench ive picked the crank and connecting rods and im gonna wait on the pistons until i know for sure what head ill be runnin. anyway tentatively my choices are as follows what do you think?

crank http://www.jegs.com/webapp/wcs/store...0002_888317_-1

rods http://store.summitracing.com/partde...0&autoview=sku

 

Those are both entry level stuff. Nothing wrong with them, but if you're going to be buying a complete rotating assembly (you missed bearings, pistons and rings) then buy it as a set, which is advertised as balanced. Unfortunately since this is a 400 you'd need to buy a flexplate as well to keep it balanced. You may be able to save money vs buying all parts seperate, then getting it balanced.

I'd pay a few coins more and get a steel crankshaft. That one is virtually identical to what you already have.

Look at ohio crankshafts. Their website isn't perfect but I know they'd have what you want, for a good price. Call them up and ask about pricing on a rotating assembly for a Chev 400cid, balanced and ready to go.

 

well just this morning the guy im getting the block from told me he's gonna throw in a 400 flexplate and harmonic balancer for 25 bucks so im good to go there. i left the pistons off because i wanted to make sure of the heads im gonna use first before i get them but ill probably go with a piston and ring kit... ill look into the ohio crankshafts thanks 4 the info

 

ok so im beginning to get the hang of all this. im not doing a 500hp build ill be lucky to get 400 out of it. so would this rotating assembly work since its balanced and is pretty much what you were talking about earlier sonix?

http://store.summitracing.com/partde...0&autoview=sku

also am i using correct numbers with the tuning tool now or is my quench off? the printscreen you attached earlier confused me a little... is 0 deck not 0 for the deck clearance? anyway here is what i figured up. thanks for being so patient with me.



edit: couldnt get chart to work so ill just post my numbers i used in order of the form

72
12
.041
4.2
4.155
0
3.75

static compression ratio = 9.933

 

That looks like a perfect kit.

You'll want to buy a "normal" composite head gasket for a 400cid engine, no biggie. Once you have the rotating assembly THEN you take it to the machine shop and say:

"bore and hone the cylinders to THESE pistons. press my pistons onto my rods and mark which hole they go into for me. Also, zero deck the engine for me."

Then you'll have exactly what you've printed above there. They should be able to look up the compression height of the pistons, and measure the deck height of the block. My machinist didn't want to do that, he just said "how much you wanna shave off", so I guessed - "uhh, .020?". Then I just used a shim gasket to get the right quench.

If your machinist doesn't want to "zero deck" the block without mocking it up, then he'll have to assemble it, measure, and disassemble. Or you can do it, then just bring back the block and tell him "take .038" off the decks" or something along those lines.

capisce?

 

great thanks a lot! im sure ill be back once thats all done with more questions, great info this is why i love tgo! i do have a quick question 4 u tho sonix... that detroit true-trac youve got. do you like it? because im sure once i tear my lil diff out of my car wit this 400 ill change to something else and ive heard true-trac is really awesome but mostly from offroad 4x4 guys... personally whats your opinion?

 

I just installed it a few weeks ago, and it's still winter here so the car is up on stands. I'll find out in april or may once I can see the ground again.

It's basically the same as the torsion in 4th gens. It's supposed to be stronger. The nice thing is no clutches to wear out. Unfortunately if there's zero traction on one tire (ice for example) then it won't lock. There needs to be a slight amount of traction. I don't think it'll ever be a problem for me, my car never sees subzero temperatures or really loose gravel or anything.

 

cool thanx 4 the info