Ok so this is definately happening now as i got a great deal on some used 400 stuff. I got a 4 bolt block out of a 71 impalla (needs a sleeve and .030 over bore) stock crank, crane cam, flexplate, new balancer, A/C Delco HEI distributor, 8 5.565 connecting rods, and 6 stock pistons for 200 bux! So im gonna list some details of my build and yall let me kno what ya think.

block .030 over to 406
trun stock crank .010 under
get new 5.7 rods (or use old ones?)
new 12.5 cc dish speed pro hypertunic aluminum pistons
cam 234/244 duration @ .050 .488/.508 lift @ .050 112 LSA
powerband starts at 3000... (maybe a problem?)
Worlds Sportsman II heads 72 cc chamber .560 lift (i'll add steam holes)
1 3/4" Hooker longtubes 3" collectors
performer RPM intake
Edelbrock 750 carb
6qt oil pan with high vol pump (high vol pump necessary?)
stock cooling from RS 305 (ok?)
trans cooler
2200-2400 TCI breakaway stall converter
torq convert lockup switch

any other questions just ask. My main worry is the cam. I got it cheap so i'd like to use it however is that cam gonna make it really bad for daily driving? Im not lookin to build anything super crazy... just mild. Ive got a few plans for beefin the 7.625 rear too. The calculators say 9.8:1 SCR 8.2:1 DCR @ .045 quench.

 

That will only happen, if you zero-deck the block; which will require taking about .045" off of it. Those pistons are an extra .020" "down in the hole" farther than the stock .025" or so, at TDC.

Your ACTUAL SCR will come out around 9.1:1.

If you want 5.7" rods, you'll do better not to use stock ones. You'll likely find yourself needing a small base circle cam with that setup; and lots of grinding on the block.

If you haven't bought those heads, don't. There's better for basically the same money. I'd recommend a set of Dart IE Platinums, 200cc, 64cc chambers. That combo, with the .045" of deck clearance, will give you ACTUALLY 9.8:1 CR. That way, you get to avoid zero-decking the block. Or, if you DO zero-deck it, get the 72cc version; but those "rebuilder" pistons are going to make that near impossible.

Yeah that cam is pretty much crap. It's OK I guess, if street behavior and gas mileage and such, don't matter. It makes OK power, but those other things will suffer.

I had a Comp XE274 in a 400 for a while; that was AWESOME. Ran REAL HARD. People who heard it LOVED it. One person's description was that it sounded like it was angry, like it wanted to jump up out of there and kill something. I would do that again in a heartbeat if the situation arose.

Cams are CHEEEP. Not worth handicapping a motor over "I got it cheap". You could get some POS for FREE, and then pay for it EVERY MONTH in gasoline; except you'd still have the POS. Totally stupid. Like moving dollar bills out of the way so you can pick up pennies.

As far as cooling, I had the stock cooling system in my car (L69 stuff), in the Deep South, with A/C. Worked fine for me. I only had it like that with the 400 for about 12 years or so though, so who knows, maybe it would have eventually had a problem?

You'll want to use a 12.8" (153 tooth) flex plate or flywheel. Have the extra bolt hole drilled in the block for the late-model starter, BEFORE you build it.

The RPM intake will be good. I'd suggest something ohter than the Edelbrock carb though. Use a Holley, manual secondary 750, such as the 4779.

You'll want more converter than that. I'd STRONGLY suggest a smaller one than stock; a 10" at the largest. 2800 RPM or so would be great. With the Neanderthal POS cam, you'll need even more than that.

 

ok so the cams out, i sorta figured that once i got the numbers off it tho but oh well. ill definately look into those dart heads and that XE274 cam sounds like it'll b a winner.

the flexplate came with the deal but ill have to go count the teeth to see if it is 168 or 153 i thought i would have to get a mini starter to clear those headers? As for the edelbrock carb i guess theres people that love holley's and hate holley's and im just one that hates them. Had 3 of em on other vehicles and have had nothing but problems. bought edelbrocks and the problems ceased.

how bout the mileage... i kno its gonna be bad but with the XE274 what did you get? over 10? being too optimistic?

 

what about these heads?

http://cgi.ebay.com/ebaymotors/ws/eB...link:middle:us

 

A couple suggestions based on my 406 build. I went with a 6" rod and flat top SRP pistons. The rods are Eagle SIR. Good rods for a good price. The combo of rod and piston was much lighter that the stock rod/piston and allowed us to lighten up the crank. This really helps the motor rev freely. I also zero decked the block because in my opinion, quench is cructial when building a motor. My quench is .039, 11.0-1 compression and run 93 octane with no problems.

Being that you will be using a carb, try to pick a cam with 110 lsa. A 112 lsa will make the motor a little lazy. You should really pick the cam after you've chosen heads and bottom end components.

 

Around 12-13 in town, 18 or so on the highway. The car had 3.23 gears at the time (I had trashed the stock rear, and stuck this junkyard one in it and then got lazy and left it there for a long time), T-5, Holley 800 carb.That's why YOU MUST get the extra bolt hole drilled.

The Eagle ESP rods are very nice, and give lots of clearance; however, they're also $600. Not alot of sense in hanging a bunch of low-bid "rebuilder" pistons on those. IMO, also not alot of sense in decking an irreplaceable block, to cheap pistons; because if you do, the block is FOREVER ruined for anything better. Can't put the metal back. My adivce would be, either use the stock crank and rods and those cheap pistons and leave the deck alone and work WITH the extreme deck clcearance, or get a REAL rotating assembly (cheapest way is to buy the whole thing from Eagle with I think they use SRP pistons) and do the appropriate machine work including decking, which will then be MUCH less brutal. Fork in the road. Cheap budget stock, or nice $$$$ forged. Not half & half.

The weak point in the stock setup will be the rod bolts first, then the crank. The crank will break in front of the first rod journal. That's what they always do, sooner or later. In fact, that happened to the motor I had.

 

Sorry I used the "SIR" rods. My bad!
Now I can say with confidence good rod for a good price.

Thanks Sofa!

 

ok so if i get the 5.7 rods ill have to do some clearancing on the block? and the speed pro pistons arent very good from the sounds of things? im not trying to build a monster motor here but i want it to last a while... so by all means let me know what would work best, but not completely destroy my budget. and im really lookin into those 215cc dart heads... would they work well?

 

That would depend on WHAT 5.7" rods.

With stock ones, yes you will have to do A GREAT DEAL of clearancing on the block. The big end of a 400 rod is shaped differently from the 350 and smaller rod, and the bolt is different (shorter, and has a different head).

On aftermarket rods, there's all kinds of variation. You'll just have to deal with whatever you end up with. Odds are though, there WILL be some clearancing involved, somewhere, although if the rods have cap screws instead of bolts and nuts, the odds are better that they will clear the cylinders and the cam. They still might hit near the oil pan rail though.I didn't say that. They're perfectly "good"; they just have a purpose they're made for, and as long as they're put to that purpose, they're fine. Like anything else in the world though, if put to some other purpose, they might or might not be the best choice. Think, suitability for purpose, and not "quality"; "good for what I'm doing", or not, as opposed to "these are pure crap" or whatever.No. Those heads are RACING parts, and if the motor is intended to actually take advantage of what they offer, THEN the "rebuilder" pistons are a mismatch. You don't put a high-HP, high-RPM, high-$$$ induction system (cam, heads, intake, exhaust) on top of a "rebuilder" short block, and get good results. Or vice-versa. Parts need to MATCH. Otherwise, you either WASTE money on something you'll never use (like big head flow on top of a short block that can't turn enough RPMs to use it), or you explode stuff (like stock short blocks at high RPMs).

Go back to what I said earlier: you're at a fork in the road.

Do you want a budget motor built out of stock parts? Then the SpeedPro pistons, stock rods with good bolts in them, and a stock or stock-replacement crank, will do fine. For that, use either GOOD stock heads (double-humps, Vortecs, the BEST late-model ones like 113s or 083s or 081s) with large valves in them and good clean-up port work done to them, or aftermarket heads with runners in the 180-200 kind of range. Use a cam that will give best results at less than 6000 RPM, because the bottom end won't last past that, very many times.

Do you want a race motor? Then forget the SpeedPro type pistons and cast cranks and stock rods. Get good-quality stuff there, including pistons that don't have the compression-killing "rebuilder" feature of sitting extra far "down in the hole", which is done on "rebuilder" pistons to keep them from crashing into the head if the block has had too ham-handed of "repairs" done to it. For that alternative, the Dart 215s would be GREAT. In that case, you can run a MUCH bigger cam; in fact you'd HAVE to, in order to actually USE the flow that the heads are capable of. Think about it.... a 215cc port won't flow 215cc worth of air, if the valve at the end is only gently cracked open and not held that way for very long.

Set a goal and a budget, make sure that those 2 things agree and are REALISTIC together (not, I want 500 HP, 7000 RPM, for $1500, 24 mpg, and 100% bulletproof reliability ), and select ALL your parts consistent with that goal. Not just a mishmash of stock stuff that's cheap mixed up with a couple of romantic-sounding big-name racing parts, because that's a surefire recipe for a money-wasting disaster.

And don't forget, when it comes to setting a budget: if you go the racing route, then PLAN ON whatever you spend on the motor, to have the same amount to spend on THE REST OF THE CAR. Suspension, drive train, and so forth. Otherwise, you'll never get to use that motor, without stuff breaking. And I can tell you, this hobby stops being fun in a hurry, when every time you step on the gas, something else big and expensive breaks.

 

Is it a good idea to build up a 4 bolt 400? I've heard they are substantially weaker than the 2 bolt brother? Sofa, can you clear this up? Is it that big of a deal?
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I can vouch for this. I'm getting about 10 in town with a Holley 700 DP, 3.23s and a T-5.

 

Yes, the 4-bolt block is weaker; I don't know about substantially weaker though.

The early blocks were a pretty radical experiment. I'm not sure why GM felt that a 400 SB was even necessary (not that I have any doubts about its necessity!!!) but they had to do alot of things that were WAY different from prior engines. The siamesed cyl walls, different rods from all other SBs, and external balance precisely because of the short rods, were all new.

One thing they thought it needed was the 4-bolt main caps. The extra 2 bolts, in the factory's configuration, help stabilize the cap in low-RPM, high-torque, continuous-duty type situations, like towing or other truck use. Since that was what they thought they would use it for, it seemed the thing to do. The first couple of years, most of them went in station wagons and such.

They learned, and improved on, a couple of things after the first couple of years. The first was that there wasn't enough metal around where the bolts go into, in the webbing; so they thickened the casting right there. Then, they decided (maybe through testing? field surveys? I couldn't say, that's only a guess) that the other 2 bolts weren't as needed as they thought, so they stopped using those more costly caps. These changes weren't all at once, like they were on one big ECO; there's 509 (newer) castings with 4 bolts, and a very few 511 (older) castings with only 2 bolts. They changed the cooling systems slightly in that changeover too.

Consequently, the thing that's ACTUALLY weaker, is the casting itself. The extra 2 bolts do penetrate, and therefore increase stress, in a critical area, true; but the main thing that's better about the later blocks, is that they're simply beefier right there where it counts.

None of this is really relevant to building a street high-perf motor though. The factory's 4-bolt caps aren't effective against high-RPM-specific stresses anyway, and so are useless for a hot-rod application; and the block "strength" issue isn't really an issue, in our application, until very high HP and RPM levels are reached. I'd say, 500-550 HP and 6500 RPM, MINIMUM, before it makes any difference at all; and even then, I'm not sure it's "significant", whatever any given person might consider that to mean.

But, for a max effort stock block motor especially with nitrous or the like, or if it will exceed 7000 RPM on a regular basis, the best setup is therefore, a 2-bolt block, with aftermarket splayed-bolt caps installed on it.

For most of us, either will do just fine IMO.

 

i guess this build is mainly for fun... just while i have a little money to play with i figured id teach myself how to do a motor swap. Im sick and tired of gettin crap from ppl in hondas and full size pickups when i cant beat em. im tryin to get somthin over 300 horse to the wheels and i want it to sound like its gonna eat them alive. as long as this build can make it 10 years and probably 20,000-30,000 miles ill be happy.

i researched for about a month on tgo, google, and people i personally know who have done such builds but i guess im still a little behind on some things. and sofa thanks a lot for all the good help.

my main goal is to build the motor and some minor suspension upgrades for around 5k. I thought maybe with those 215cc heads since they are cheaper than than lots of other 195-210cc it wouldnt matter if i didnt use all they had to offer and i would have something i could use in the future. but i guess ill definately look into something else around 200.

the 5.7 rods i found said they were clearanced for stroker applications so i just guessed that they would work with my non stroker setup. if i find that ill be spending more getting the block clearanced for the 5.7 rods ill just use the 5.56 rods and see if i can get the bushed ends in them for floating pistons, if not ill just use pressed ones. will that work?

 

I personally would prefer the 2 bolt but am not scared of a 4 bolt block either. A friend of mine used a brodix headed 4 bolt 406 for bracket racing in a 68 camaro for at least 5-6 years with no issues and it was a circle track engine for 7-8 years before. Sure it was freshened but not every year and I bet he made 100 or more passes a year with it. He shifted at 6200, had good swap meet parts in it and it ran 6.5X's at 105 consistently. You'll like the 400.

 

Yes, that works; however, by the time you buy the rod bolts (which YOU MUST do, unless you think you would enjoy sweeping up bottom end parts that came through the oil pan) and the bushings, and pay to have the bolts changed, the small end bored and bushed and honed, and the big end re-sized, you may well have more money in them than you would have had to spend for new ones.

DO NOT get stock rods that have "been clearanced for stroker applications".



This pic that gives you an idea of just how big the rod bolt on a stock 5.7" rod is, and how bad of a clearance problem you can end up with.Would you pay money for a set of stock rods that had been ground down to give the same clearance as that Eagle rod?

Unfortunately I don't have a 400 rod laying around to take a pic of for comparison, I'd have to tear down a motor to get one and I'm not going to do that.

Anyway, sounds like the right "system" to shoot for, is a strong street setup; not a stock one, but also not a max-effort race one; one you can build once and not have to worry about, for street use.

For a really strong stock-like street motor, try one of the cheaper Eagle rotating assemblies, such as this one here which you can see the specs for in the Eagle Catalog. I don't think you can come close to that price trying to piece it together.

Then, get a set of these Dart heads which in this condition are ready to bolt on and set up well for an aggressive cam, the XE274, a set of Comp 1302 1.6 roller rockers, a Performer RPM Air Gap, and a Holley 800-850 CFM manual secondary carb about like this one. You'll be seriously ready to roast some imports.

 

awesome thats what i needed to see! thanks again sofa. but now from the eagle catalog you linked i have a question. how are they figuring the compression ratios for their different rotating assemblies. like 13012 and 13014 theyre both -5cc the only difference is one is inverted dome and the other is flat. how is the compression so different? just curious because the kb cr calculator i use http://kb-silvolite.com/calc.php?action=comp says their total quench would be like .120 to get an 8.7: cr with 5cc dish volume pistons, which is absolutely totally ridiculous. just not sure what im doin wrong?

 

Think about not using the short rods. It is one of the reasons the 400 was not the best at high rpm. Read about rod angles and side loads on pistons.

The deck height is different or piston is down in the hole. Squish engines are more like .04 to .06

search is your knowledge

 

I don't know exactly whatpistons (part #) come in that kit. Call Eagle and ask.

That kit has the 6.00" rods.