hey, i have a chance to buy a 400 longblock for 300 bucks its used and a 2 bolt main 817 1974' casting wondering about the specs of the heads and cam
and good potential replacements for a sick street setup thanks in advance!

 

A 1974 is gonna have smog heads which are worthless. Would toss them and buy any budget head before using those heads.

 

350 vortec heads.

 

great block don't know about heads but I would get it just for the block. The two bolt main is the strong one.

 

also im wondering if the TC on my 700r4 will bolt up to the stock 400 flexplate no problems?

 

Yup; might have to elongate the holes slightly, the circle is very slightly different.

The heads and cam are GARBAGE, if they're the 74 stuff. You don't even need to know any "specs". Just trash em and start over. Check the casting #s first of course, to make sure. Would have come with 624 or 882 most likely.

 

I've got a book of "engine" builds and one of them uses a 400sbc...looking at one right now with 427hp and 500+ ft-lbs of torque at under 5500rpm. Not saying you're looking for that size motor, but I'm just saying... lol

 

that would be pretty sweet, id love to b faster then a new camaro lol
i can get a set of 72 400 heads, are they any better?

 

I would stay away from an of those old heads. Personally, I would look into a set of vortec heads or some World or AFR heads. Yes, they are expensive but you want the motor to breath properly.

 

If you're looking for cheap, get a set of vortec heads and get the steamholes put in them like mentioned. Putting old stocker heads on a nice 400 sbc is a horrible decision with so much potential power there on the table.

 

yeah your right, i want at least 300 hp any ideas on good cams for a street engine? and carb size

 

Call lunati and tell them what you've got. I'd go with a 750 mechanical carb, personally. Kinda need to know what pistons you've got in it though to make a cam selection, as well as overall compression ratio (among other things).

 

1st things 1st. In my eyes your only going to use the block. If its good.
strip it down to the block and take all to the machine shop to check the bores, block 4 cracks, thickness of cyl walls and all the other cool stuff.
If you want it to make decent power also throw away the heads, cam, complete rotating assembly and use all aftermarket.
You said you only want 300hp? you can do that easy with a 305-350.
You need to make a plan 4 what you want to do with the car and a budget then stick to it.
I would run nothing less than a 210cc In runner head and a hyd roller cam. def stick with EFI and a nice overdrive trans if you plan to drive it a lot. I would do a complete aftermarket internally balanced rotating assembly. The stock cranks are weak and will crack/break. I have 6 cracked ones here.

You have to be honest with yourself and and the budget.. all the little things ad up fast. good luck

 

I'd have to disagree as far as a streetable,honest 300-350 hp street engine is concerned.I have heard horror stories about cast 400 cranks,but have personally beat the ever loving **** out of them,without failure.
Blocks on the other hand,not as fortunate.I busted 2 before I gave up,but that was at a 650 hp level.

350 hp should be a cakewalk,this is my advice and worth every penny it costs you:
Properly prepped block,no more than .030 over bore,and align hone it.
On the heads,195cc is more than plenty for a street engine.A roller cam is always better,but a flat tappet will easily reach your power goals.
Vortecs are great heads,it's just been my experiance that by the time you've spent the cash to make them work,aftermarket heads will cost about the same,and make more power.
Spend the money on balancing the rotating assembly,balancing will add more life to the engine than anything else you spend money on,proper assembly aside.

Top it off with a Performer RPM style intake,you should be well in excess of 350 HP.

 

they should make 300 stock seams like a wast. I'd be looking at 450 with good top end but others are right make your budget then build. That's the first about 2bolt not working at higher hp but does not mean its not true. So do supports. better to build strong bottom end and spend money on top end as you get it. Cast is good to 500hp and is cheap but do forged piston don't skip out on piston. I don't like kb pistons know to many people who had problems with them.

 

This is my beginnings of the tear down, got to pick up an engine stand later today.

 

I started my engine build with pretty much the same motor. I decided to keep the crank since it was in good shape and checked out. I agree the first thing to do is get the block checked out. Once you've determined it's OK, plan the rest of the motor.
Here was my recipe:
1. Cleaned and prepped block.
2. Used stock crank but upgraded to6" rods and SRP flattop pistons.
3. Bored block .020(that's all it needed.
4. Align honed mains.
5. Zero decked block (quench is critical).
6. Balanced rotating assembly. Make sure you have your exact flex plate and balancer. We were able to pull weight out of the crank due to the much lighter pistons and rods.
7. I recommend using somewhat higher volume oil pump along with higher pressure. Milodon has a pump with 10% increased volume and additional pressure.
8. I used Brodix RR200 heads with 2.05/1.6 valves.
9. Solid roller cam with 4/7 swap.
I've built quite a few motors and this motor has the best throttle response and overall power.

 

The theory behind the 2-bolt block not working at higher RPM's is that supposedly you can get "bearing walk", where the bearings spin out at higher RPMs, but I think we're looking at 6500+RPM there. Fords only run 2-bolt blocks and they don't have any problems so I think it's as much the "quality" of the build as anything. Besides, this block can make 500hp without ever hitting 5500 RPM.

For parts...I can list the 470hp build if you want me to. I"ll scan it in and post it, it's in a book and dynoed so with those parts you're guaranteed to hit those numbers with that build.

650 Carb is all you need for the motor. I'd get a Qjet, but that's my preference. Best all around carb once it's tuned. Qjet is a 750 cfm carb.

Performer RPM intake
AFR 195 Angle Plug heads (best heads on the market I think). I'm running World Sportsman Heads on my 355 and they are perfect, probably a step below the AFR's though.

To run a roller cam in that motor, you'll need to get a set of Retrofit roller lifters and retrofit roller cam because that block wasn't made for it. Hydraulic Roller motors didn't come out till 1986 for street use. As previous poster said, once you figure out what you want, call Lunati or Comp Cams and tell them what you've got, let them help you pick the cam.

I'd get a Scat or Eagle rotating assembly, forged if you are looking for anything more than 450HP.

For pistons, you'll want to stay in the 9.1-9.5 compressions ratio area to keep it on pump gas. I don't trust the octane readings on the pumps, so when I built my motor, I gave up probably 50hp and dropped the CR a bit so I wouldn't detonate if I got crappy gas.

Best of luck!

 

I can't second this enough. Once you figure out what you think your budget will be, double it. Then you'll know about how much your going to spend. I went into mine without accounting for it and was I suprised. I figured 3500, spent near $7K once it was all said and done.

 

i can get a set of heads off of a 91 350tpi from a GTA for 50 bucks so i may go that route, will these heads work with this cam or is the lift to high? http://www.jegs.com/i/Edelbrock/350/...92#moreDetails
i like the look of the graph! tho i dont expect to get the gains it claims with just tpi heads

 

Another Ave that you can take is a 377... 400 Block, 350 crank/rods, I've built 5 of these and I absolutely love them... It will turn higher than the "same" set up w/ 400 crank/rods...

 

Only 377 I ever built, I couldn't talk the customer out of... he then proceeded to expect me to re-build it right, because he got his a$$ whupped coming up off of EVERY corner by the 400s. Wasn't as bad on a slick track but on a tacky one you could just watch the missing 23 CID kill him as the other guys looked like they had about 30 more HP. For some unfathomable reason. Imagine that... Oh I forgot, it's because, THEY DID. Ignore that idea.

That Edlebrock cam is a crock of excrement. It's the same lobes as these right here http://www.summitracing.com/parts/SUM-1102/ and http://www.summitracing.com/parts/SUM-1103/ : the generic copied generic copy of a generically copied generic copy of a generic cam copy that Vic sells uses the same 40-yr-old lobe designs, except that it's PARTICULARLY bad for a 400 which will, ABOVE ALL, need help on the exh side. A cam with a bigger exh lobe will ALWAYS run better in a 400 than one of those ... other ... ,,,, .... camshaft-shaped objects.

Here's what you REALLY need.



The L98 heads are better than most stock heads but not a good choice. If you really want to get the full benefit of the CID, aftermarket ones are the way to go.

 

My 400 has seen 8,000rpm quit often and has more power than a 377.

 

Regal - The TPI heads will work on your 400 just that they will not make the power that aftermarket heads will. For a cam, you should look into the Lunati VooDoo line. I agree that a single pattern cam is not the way to go. You definately need more exhaust duration. Another choice you may want to look at is the Comp Thumpr grinds. The much longer exhaust duration will help.

I used a set of the TPI heads on my 84 Vette that I converted from Crossfire to TPI. I also picked these up real cheap. I disassembled mine and found the bowl to valve seat were severely mismatched. I used my die grinder to get the best transition I could. I also made sure to put new/better valve seals on. Overall the motor made good power.

Your 400 even with these heads will make killer torque.
Good luck.

 

Basically im looking for a high torque set up i live in a area with a lot of hills and the lg4 tends to loose momentum near the top i want to get the 400 running on the cheap and pick up a good set of heads when the budget allows me too. plus in my opinion its just cooler to have a 400 than a 305

 

This is strait from a book I have on how to build big small block chevies. This motor makes 427HP @ 5100RPM and 525ft-lb of torque @ 3500RPM.

Engine, 406cid (4.155 x 3.75)
Compression: 9.5:1
Block: Factory 400
Crank: Scat Cast Iron
Rods: Scat 4340 I-beam
Pistons and rings: Probe forged dished, total seal 1/16"
Oil Pan/Pump: Stock
Cam: Lunati Hydraulic Flat Tappet 230/230 @ .050, .455/.455-inch, 114* lobe separation
Rocker: 1.5:1 Harlan (can also use Comp Pro Magnum)
Cylinder Heads: Stock Iron Vortec 1.94/1.50
Intake: Edelbrock RPM Air Gap Vortec style
Carb: HP 750 Holley
Ignition: HEI
Headers: 1 5/8" Hedman w/2 1/2" duals

 

And that motor would probably make 40 more HP with a modern cam, than with the old Bracket Master; since it has such a small exh lobe (in relation to the intake) and is mated with heads with such poor exh flow (in relation to the intake). Serious mismatch of cam to heads.

I would also NEVER put aluminum rockers in a motor intended for street use. There's A WORLD of difference between racing, where for example if you run a motor at say 7000 RPMs for say 12 seconds (1 pass), the motor only turns 1000 times, and each rocker therefore only operates 500 times; but in a street application, those rockers see more than the equivalent of that same pass - 1000 engine revolutions - every mile. Meaning, in a typical short lifetime of a "performance" motor of 100,000 miles, the rockers see the equivalent of AT LEAST 100,000 passes. Aluminum fails by the mechanism of "fatigue", which any of you guys that are A&P certified know EXACTLY what I'm talking about; it's why in aircraft, certain stressed parts are REQUIRED to be REPLACED - not "inspected", not "tested", not anything else, REPLACED - every x hours, x landings, x ascent-descent cycles, or whatever the stressor on that part is, because aluminum just UP AND BREAKS out of the clear blue and gives no signs or warning beforehand. The lifetime of an aluminum rocker on the street is a Poisson distribution with a mean somewhere in the 10,000 - 20,000 mile range. Bad idea. Use steel instead; Comp or Crower, NOT some cheeeeeeeep Chinese knockoff like CAT or PP (if they're importing them too yet).

 

I'm just quoting what the book has, I am not an expert at this by any means but I do agree with the aluminum aspect of it. Why I recommended the Comp Magnums, they are all steel. As for the rest, I'd have to defer to those of you with more experience but I can't disagree with anything you've said. The book was printed in 2003, so the info is a bit older, however, if they aren't strait out lying to us, it's still a powerful street motor which is what he was asking for at 500+ ft-lb of torque and 400+hp. Throw some AFR heads on this thing with a modern thumper or retrofit roller cam and yeah, eastily 40+ more hp.

 

so what do you guys think of this for a good cam? http://www.jegs.com/i/Lunati/638/601...d=#moreDetails

 

Check out the Lunati 60102, some guys use that in their 305's and 350's. However with the one you posted you could use the Vortex heads.

 

Agreed; the 60101 is too small for most 400s, but the -02 or -03 will RIP in a street setup with Vortec heads. Perfect design for the situation at hand.

 

I like the 60102 for your 400. You'll crap your pants the first time you take the car out with this motor.

 

My uncled used to have a Hemi 426 in his road-runner, he'd stick a $20 on the dash and say "If you can grab it before I hit 60, it's yours. I don't think he ever lost.

With this motor? You'd never lose...as long as you can get it to hook up, it'll put you in the trunk! hahaha

 

Sorry bud,but your uncle is full of ****.

 

Maybe, but I'll let him keep his stories that impress teenagers.

 

any info on the 920 casting? 80 bucks for a bolt on and go set!

 

#1 cylinder in my block has some pitting in it, it will clean up at .030 over im using what i think are 64 cc heads so i want to keep my compression ratio pump gas friendly how deep of a dish are in the stock pistons and how much piston do i need to keep it in the 9"s?

 

If you already have the block at the machine shop, you really should have the blocked decked so you can set the quench at .040". With the 64cc chambers, you will need a
20cc dish. Getting the quench right is very important in making good power and creating turbulence in the combustion chamber area. This will be more critical to running pump gas than the compression. I run 92-93 in my 406 without any problems. My motor has 11.0-1 compression. That is because I decked the block and use a .040" head gasket.
I'm assuming you are using later model cylinder heads with a swirl design combustion chamber?

 

im using a set of over the counter replacement heads from 69-70 #370 64cc 1.94/1.50
id like to run 87 if possible

 

What happened to the heads from the GTA? These would. Be better imo.

 

didnt't pick them up, listing went off the classifieds, and these heads fit my perf eps intake also a fresh rebuild

 

So you're just gonna run a regular low profile performer EPS intake?

 

yepp i need it to fit under the stock hood for now anyway, just gonna do the eps intake headers and a custom 3 inch exhaust

 

i think im going to go with the - Sealed Power Z400AP30 pistons it says this about the dish - Recessed piston head is 0.160 inch deep x 3.445 inch diameter. anyone know how to get the cc out of that?

 

Volume of a cylinder:

V=h*pi*r^2

V= .160*pi*(3.445/2)^2)

1.49 cubic inches -> 24cc dish.

Why are you going with regular cast pistons? You're not even going to get hypereutectic pistons? Those are also meant for stock 5.565 inch rods. Are you reusing the factory 400 rods?

 

GM used aluminum rockers on the LT4 corvette. Ford used them on 93 Cobras. They have to pass a bunch of tests to be put on a production motor if i'm not mistaken.
When installed properly with spring pressures they are designed for, they are fairly reliable. All the 5.0 mustangs I modded 15-20 years ago are still running aluminum rockers I put on them with no problems. Mostly street cars but some do hit the track a bit. A bunch of these cars have over 200k miles on em.
Now when your stabing them on a solid roller cammed race engine dirven on the street with huge spring pressures, your prolly going to have problems. ESP with the cheap china junk. I'd stay away from that at all costs anyway..

 

yeah im keeping the stock rods, cast pistons, doing it all on the cheap.... its bassicly just a highway cruiser see's about 3000 - 4000km a year i dont see the point in throwing a ton of money into a forged rotating assembly, I wanted a 400 now i have one haha.