7thdarkangel

I picked up a 400 block a couple of weeks ago. Right now it’s as striped down as it can get. My plan is to completely rebuild it. I debuting whether or not to do a .030 over or leave it stock. The stroke is probably going to stay at 3.75. Looking to get 64cc aluminum heads or use a set of 350 fuely head I have lying around.

So what kind of cam options do I have or what should I look for?

Any help would be great.

Apeiron

64cc chambers are way too small on a 400, and fuelies are obsolete.

What are you planning to do with the car?

Guest

The trouble with 64s on a 400, is two-fold. First, most of the better 64 cc heads are also offered as 72 cc, or so.
Second, the 64 cc heads require quite a dish in the piston. This isn't a deal-breaker, but it isn't desirable, either.
You need to finalize your future use of the engine, then your choice of heads, before choosing pistons, then a cam.
Whether or not to bore, and if so, how much, depends entirely on the amount of ring ridge at the tops of the bores. If this block needs more than you want, you may have to change plans or change blocks.

sofakingdom

iTrader: (1)

A dished piston can be desirable, IF you get an "inverse dome" piston instead of a traditional "dish".



If all else is equal (which as we all know it rarely is), having a compact, near spherical chamber formed by both the upper surface (head) and lower one (piston) is always better than having an irregular one, or worst of all, a thin spread-out one (large chamber & dome). Consider setting fire to a piece of paper: if it's wadded up in a ball, it will light and burn completely, much more quickly than if it's flat.

Pistons like this tend to cost more than typical flat-tops or dished ones, but can often be worth it.

Obviously you would need to plan on heads and pistons together as a pacakge, to come out with an appropriate compression ratio.

Cam options are the same for a 400 as for any other small block. They tend to want a bit more than a shorter-stroke motor though.

Don't forget to drill the steam holes in whatever heads you end up with.



Pretty easy to do yourself. Gotta be easy, if I can reliably manage it.

7thdarkangel

from the looks of it, im 99% sure im going to bore .030 over(http://www.summitracing.com/parts/ESP-B13470030/) you are right about the heads. ill probably just have the stock heads machined or fine a pair of 75cc heads. the engine is going to be used as a weeked driver with the chance of going down the strip every now and then. i want the thing to move and still idle well.

7thdarkangel

i meant vortec i think they have bigger valves than what came on the 400. ill have to double check when i get home.

Guest

Duttweiler and some others like him prefer perfect dishes rather than reverse domes, and the reason they give has something to do with trying to keep the pistons from rocking in the bores, IIRC.
Stock 400 heads are no way to build performance. Better to use Vortecs with dished pistons than big-valved-and-ported 400 heads with flat-tops.
Buy the best heads you can afford, even if you have to run a stock intake manifold until your funds recover.
No 400 ever came with valves larger than 1.94 / 1.50". But neither did the Vortecs. Valve size isn't everything.
Drilling for steam holes: it's not enough to just use the 400 head gaskets as a template, some of the holes must be drilled at an angle. Research it before trying it.

7thdarkangel

ya i know all about the steam holes. what heads/piston setup would you recomend then. as for the intake i was going to use the manifold off the 350 for the time being. http://www.summitracing.com/parts/EDL-50011/

sofakingdom

iTrader: (1)

That's a ... kinder, gentler way to say it ... than some of us would.

Stock 400 heads SUCK. All 400s were low-perf, 2-bbl, grunt type motors in trucks and sedans. None were ever set up for "performance" from the factory. The heads are all the worst of the worst; garbage like 882, 624, 993, etc. It's astounding that they did that, and never made a 4-bbl one, when that seems so obvious in retrospect; but I guess it is what it is.

Vortec heads are MUCH better then double-humps. Although I happen to have a 400 sitting in my garage with DHs on it, that I ran in my 3rd gen for many many years (for most of a decade before Vortec heads even EXISTED, in fact), I would not re-build that combo today. Too much has changed and rendered it totally obsolete.



The steam hole drilling is trivial. Use a 400 HG as a template; center-punch; use a 3/16" bit in a hand drill, that's all you need; drill the holes on the exh side straight; on the int side, start it straight, then after it's into the metal 1/8" or so, angle it toward the exh side about 30°. Reason being, as you can see in the pic of my Dart heads up there, that hole is RIGHT NEXT TO the head bolt hole, and the "tubular" feature cast into the block, is about 3/8" thick, and therefore if you drill straight, you can drill all the way to the rocker gallery and never hit the water jacket. You have to go to the side to break out of that "tube" wall.

I would NOT EVER build a motor with a round dish, if I can help it. That is one of the all-around worst possible piston configurations. Not only does it have the afore-mentioned chamber-shape problem, but also, it inherently has no quench, meaning, a higher tendency toward detonation at any given CR, all else being equal, than a piston with a significant flat top. Dome = worst; round dish = bad; flat-top= better; inverse dome = best. IMHO of course.

Guest

Round dish versus reverse dome needs to be back-to-back comparison tested. And then the results made public.
Until it is, it's about theory and personal preference.
I wasn't advocating either style of dish.
But in the world of facts, there were 400s built with Q-Jets.
There were also 400s built for truck use, that came with 1.72" intake valves.
None of this is helping 7thdarkangel.
Best is large chambers, like 75 cc AFRs, for one possible example, with flat top pistons.

7thdarkangel

i personally have a mind set on flat tops. i just need to do some research on what heads to use. more than likely end up with a 72cc or 75cc head. as for the cam i was looking at one of the lunati voodo cams, i think it was the 256/262 cam kit.

sofakingdom

iTrader: (1)

That head/piston combo should work OK.

Watch out for the deck clearance: which is, how far "down in the hole" at TDC it is. Stock, that distance is .025" nominal, and usually is a little more. Most replacement pistons add .020" to that, meaning, the top of the piston will miss reaching the deck at TDC by about .045" - .050". Don't forget to include this in your compression "calculator".

That's a REALLY little cam for a 400. I think you'll probably want more than that. Probably, at least the one 2 sizes larger in that series; 60103 IIRC.

And of course, don't forget to drill the steam holes in your heads. Contrary to whatever else is posted up there, it's something you can easily do yourself, in your own garage or yard with your own tools, in a matter of minutes. Just don't break off a drill bit in the deck, that's a HASSLE.

7thdarkangel

ill look into a bigger size. the reason i was looking at that one first was the rmp range. unless im looking at it wrong wouldnt the street drivablity go down with a bigger cam? as in sloppy idle?

Guest

Those RPM ranges they give are for stock-headed 350s. More cubes needs more cam.
If you like Lunati, that's fine. But those Voodoo cams are on a 112 lobe separation angle. David Vizard says that SBCs with a 3.75" stroke should use a 106 degree lobe separation, but if the heads flow really well, they can use a 108.
However, that Dart 400 I was referencing in that 383 thread was using a 236/242-110 HR cam. That 400 made 410 TQ at 2000 rpm, 445 at 2500, 474 at 3000, 481 at 3500, 511 at 4000, 517 at 4500-5000...
Surely that's a strong, desirable torque curve with plenty of low-end torque. Most 350s don't make 410 ft-lbs at any rpm, here you get it by 2000 rpm.

7thdarkangel

call a local engine shop. they can get me a set of loaded aluminin heads 75cc for about $900. they also have a set in the shop 76cc gm high flow head loaded cast iron but they have a max .5 lift. $425. right now 900 a little high for me time being. i think ill stop at the shop after work and see what the cast iron heads look like.

sofakingdom

iTrader: (1)

Look at the casting number FIRST. If they are any of the ones I posted above, PASS; no matter what size valves they stuck in them, how uniformly gray and non-rusty they are, or what other eye candy they offer. They are not worth the price, even if the price is FREE. I've paid people to come haul off piles of those; meaning, their value is NEGATIVE, besides scrap vaule (not high enough for me to be bothered with at the time) or what a sucker can be fleeced out of by putting lipstick on the pig and telling him it's a supermodel movie actress rock star now.

Guest

Put the project on hold if you must, but get those $900 heads. Or you'll wish you had.
There aren't any iron 75 cc Chevrolet heads that are adequate for a performance 400.
The upgrade is effectively $475 if you do it now, versus $900 if you do it later.

7thdarkangel

i got off the phone with the shop. i can get alum heads bare for $600 which is in my budget and thats pretty much how i want them. the iron heads are just 882s. i think im going to get the alum heads in a week or so after all the medical bill are payed off.

gwarren007

iTrader: (1)

http://cgi.ebay.com/ebaymotors/327-3...Q5fAccessories

Guest

I'd spend the extra $100 and get those.

7thdarkangel

those heads look pretty good.. ill see if i can get some money together and order them. so with those heads and a set of flat top to compliment them... which on of these cam sets would be best?

1. http://cgi.ebay.com/ebaymotors/ws/eB...=STRK:MEWAX:IT

2. http://cgi.ebay.com/ebaymotors/LUNAT...item2eb5a9cd7f


and how would it idle? idle being about 750-850


(and yes i like the voodoos)

skinny z

Something worth mentioning (and not brought up here) is whether the OP's 400 block is WORTH rebuilding. It's good advice to investigate that block with a sonic check of the cylinder walls. It wouldn't add much to overall cost of the build and could save thousands in the long run. 400 blocks suffer from core shift (as do all OEM blocks). The result of a .030" overbore (and I can only recall once in the last decade where I've seen a standard bore 400) COULD make the cylinder wall dangerously thin. I have personally witnessed more than one overbored 400 that's had a cylinder go down becasue it split adjacent to the head bolt.
I'm not saying it WILL happen, just that it MIGHT (That's from personal experience. I can elaborate if you wish). Sonic testing isn't that unusal anymore and it could save you a headache down the road.
This is assuming 7thdarkangel hasn't already performed the described testing.

7thdarkangel

that testing has not yet been done but will be done when getting ready to order pistons. when that gets done i will also find out if i "have to" bore the engine to make up for wear. the main things im concerned about were the heads and cam. i can work around the pistons.

also here's the mess i mad/ will have to clean up this weekend.

gwarren007

iTrader: (1)

You didn't put the main caps back on the block where they should be oriented? Why?

7thdarkangel

they were going to go back on after the crank came out but then realized i had to leave for work. so they were marked and put aside. i havent gotten back into the garage in a few days so thats were they sit till i can get so time in there

7thdarkangel

still any input on the cam?

Sonix

iTrader: (1)

I ran the Voodoo 60103, and it was surprisingly tame in my 350. If you're going to get aftermarket aluminum heads, and it's on a 400, it'd step up one more, to the 60104. That would still idle smooth, albeit a bit lumpy, on a 400. No worries about it stalling at lights, or lack of power brakes, but it would let the driver next to you know you've got something under the hood (and would have the power to back it up).

7thdarkangel

just remember this is going to be more street than strip. so it need to be drive able. now what would the "rpm range" be on that cam in the 400 with aluminum heads?

Sonix

iTrader: (1)

Take the advertised RPM range, and subtract 300RPM from the starting and ending, and that's about where it'll be.
If it'll be mostly street, you can use the 60103. Nothing wrong with it, it'll still be quite hot.

7thdarkangel

would the 60103 have a sloppy idle and drive up until 1500rmp then?
sorry for the stupid questions. cams are not my thing

Orr89RocZ

iTrader: (20)

Well with a mild build that cam will be extremely driveable. My motor is a mild compression 400" motor with AFR 195's and I run a 292/292 233/233 hydraulic roller cam. 9 to 1 compression. 4000 stall and 2.73 gears it puts around extremely well off boost. Its very driveable. You can put a big cam in a 400 and be driveable because they have alot of torque. My cam could idle smoothly with some lope at 800 rpm but I chose to keep it around 950 as its more smooth.

As long as the fuel delivery is good that motor will be streetable. You could go next cam size up and be good to 6K rpm with a 195-200 ish cc head. I wouldnt go smaller on the heads for a 400. I shift around 5800-6000 on my setup..its really too mild but a great street setup.

7thdarkangel

the stall on the 700r4 is at 2000rmp does that make any diff? and yes the 700r4 will handle the 400.

Orr89RocZ

iTrader: (20)

Cam is mild enough that stock stall would work so 2000 aint much over stock so it should be fine. I've tuned my friends car with a big cam in a 360" motor on stock stall 700r4 trans and it ran just fine. 230/236 .576/.570 cam 113lsa in a 360" motor with 800 rpm idle. Worked well but that was EFI. Ran much better with aftermarket 3600 stall tho For driving its nice to have less converter.

InfernalVortex

iTrader: (4)

Its Revolutions Per Minute. RPMs.

You need to make sure that block is worth the effort before you start buying a bunch of parts for it. If it cant be overbored you're gonna have a pile of 400 specific parts and nothing to do with them except sell them at a loss.

Valve size isnt what determines how good a cylinder head is, either.

skinny z

What he said...

7thdarkangel

nothing has been ordered yet. the block is going in to get checked either tommorow or friday. as i stated before i know about the checking i just needed info on the build. besides i could alway get another block.

thanks for pointing out the obvious.

7thdarkangel

Well the block is at the shop getting cleaned, fluxed, checked, cam bearings, and preped for the bore. As well as other things as it goes.

skinny z

I'm curious to know what they charge for sonic testing. That's the most critical part of an OEM 400 block build.

7thdarkangel

$175 for the cleaning, sonic check, and magna flux.

skinny z

Sounds reasonable.
The only reason I've brought it up is what happened to me when I went to rebuild my 400 block. This was a one owner engine from a 1977 Chevy van (mine). I went to my machinist (well known, well repspected), told him what I wanted to do and he more or less said he didn't want to do another OEM 400 block. He showed me 3 or 4 scrap blocks that had all split in the cylinder wall directly adjacent to one of the head bolts. He said the problem has occured when using torque plates while boring/honing or even after the machining was completed and the cylinder heads torqued down and the engine had been in service.
I even went so far as to contact Kevin McClelland at Chevy High Performance. My letter was published under the title Sonic 400 in the April 2005 magazine. He talked about the inherent problems with the OEM blocks and supported my machinist's point of view.
Convinced me to build a 350 instead.
That said, it doesn't mean it can't be done. It's probably done all the time. With the aformentioned testing completed on your block, you'll know whether or not to proceed.

7thdarkangel

i know its been a while but i got busy. the block got tested and came back clean. according to the machinist the block was like new(score for me). going 30 over with. I should be getting the block back in a month or two. the pistons have already been delivered to the shop. cranks getting balance as well. heads should be coming in a month or so.
thanks for all the help.

7thdarkangel

i know its been a while, but ive been busy. the engine is just about complete. just have to finish adjusting the rocker arms and its done.
so here are the specs.
.030 over flat top pistons from SRP
rebalanced the crank
74cc aluminum heads
cam set from luniti 268/272
compcams full roller rockers
edelbrock torquer 2 intake
edelbrock 750cfm carb
edelbrock air cleaner and soon valve covers
new hooker headers (still in box)
unfortunately i have to wait till im done painting the engine bay to get this thing in.

skinny z

Looking good.
Which heads? Any other cam specs?

7thdarkangel

cam is the voodoo 60103. @.050 its 227/233, lift .489/.504


the heads are the ones similar to the one that got posted earlier. just i got mine ported.

7thdarkangel

well the engine is in, running great, and almost ready to be driven. going to be stripping the body down this week to get it all smothed out and primed. it will get the color and clear in the fall. hopfully i can get to drive this thing a couple of times this year.