Thread: 400 sbc build

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Originally Posted by techinspector1

This sounds bogus. Have you run the numbers on the block?
http://www.crankshaftcoalition.com/w...lock_codes.jpg


At the rate of $10 per horsepower, I doubt this will be enough. Plan on spending $1000 just for squaring up the block, boring, honing, working the main bearing bore, cutting the decks to the stack of parts you will use, etc. And that's if the 400 bore is stock. If it's already bored +0.030", you will likely want to find another block. A +0.060" Chevy small block generally leaves some part of the cylinders too thin to cancel harmonics that are set up by the piston rings skidding up and down the bore. (You may have thought that the rings slide smoothly up and down the bore.....NO.) If left uncancelled, these harmonics will separate the cooling water on the other side of the jacket into water and air bubbles. The air bubbles then cling to the cylinder walls on the water jacket side of the cylinder and prevent cooling water getting to the cylinder to carry away heat. The result is an overheating motor that you cannot cure. The block is junk.


And I'm sure you know that this will be another $1500+ for the differential, new control arm bushings and shocks.


Pretty pricey, but if it works, great. Says it will support 650 hp, so would support anything naturally aspirated. If you were to use a turbo, you'd have to cut back on the boost.


Use Edelbrock 7101 or Weiand 8150. Do not use an air gap intake manifold. Experiment with spacers. You would leave 30-40 hp on the table with the shorter Torker manifold.


These are OK heads, but would not be my choice. Profiler 195's would support 500-550 naturally aspirated and they're less money than the Brodix units, about $1200 for a set complete.
https://www.profilerperformance.com/...ree-heads.html


I know nothing about EFI, so you're on your own here.


Not apr, ARP. Studs will not be necessary and are a genuine pain in the ass when it comes time to pull a head with the motor in the car. The heater assy is in the way on the passenger side and the brake booster is in the way on the driver's side. Just use a quality head bolt. Use Fel-Pro 1014 head gaskets, 0.039" compressed thickness. Together with a ZERO deck, these will give you a 0.039" squish/quench, eliminating detonation and pre-ignition. Here's a pretty decent article explaining the two....
https://en.wikipedia.org/wiki/Engine_knocking


If this cam has been run before in another motor, then it's junk except for running in the motor where it was run before, with new lifters. Don't ever run a flat tappet cam in two different motors. It's not a good idea. There are other places to save money. I don't like these aggressive grinds on the street either. They're very noisy and put undue stress on the valvetrain for a street motor. Now, if you are 100% drag racing the motor and are looking for every single horsepower in a competition venue, then yes, go for it. For the street, I would prefer to pull back on the Hydraulic Index (subtract 0.050" duration from advertised duration to find H.I. For instance, 230 subtracted from 290 equals 60) and use a milder grind for the longevity of the motor. Harvey Crane came up with this way of looking at the rate of lift of a cam lobe (H.I.). He used 62 for years and years and built an empire on Crane Cams, because they performed well, were quiet in operation and lasted a long time. In recent years, other cam grinders have begun to use faster ramps to get a little more horsepower from the lobe design. While this works, it also puts additional stress into the valvetrain. An H.I. of 65 to 75 would be a very slow and easy ramp, something generally used by cam grinders like Melling for a bone stock rebuild where you want to get a lot of life from the cam with dead-smooth and very quiet operation. Other grinders will use an H.I. of maybe 40 to 50 H.I., which works the lobe and all other valvetrain parts very hard. This generally results in a very noisy operation as well. I like to use a range of 52 to 62 in a street motor for relatively quiet operation and good power. Everything is a compromise.

Trying to use a flat tappet cam in today's world is just foolish. Here's a tutorial that I wrote for another forum several years ago, when we started fragging cams as a result of the oil manufacturers pulling extreme pressure lubricants from motor oils.
http://www.crankshaftcoalition.com/w...ips_and_tricks

Match up a good hydraulic roller cam to your static compression ratio and operating range and forget it. If you are wanting some lope from the cam, then you will have to raise the static compression ratio up to match up with the cam. Low static compression ratio, short cam. High static compression ratio, long cam. When we get a little further along with putting this build together on paper, I'll help you to choose a cam and show you why I used what I did. Of course, you have the option of calling up the cam grinders and talking to their engineering department for a recommendation after you have all the other parts and systems of the build nailed down. The LAST part you buy for the build should be the cam and lifters. I like Howards roller hydraulic cams and Howards roller hydraulic lifters, bought as a kit together. (CL in front of the part number).

I would not use the roller tip rockers, particularly if they are CompCams Magnum units, with the ball socket fulcrum. In my opinion, those are junk. If you want to use roller rockers, use Scorpion aluminum roller rockers. They're affordable and of good quality. The power gain and oil temperature reduction with roller rockers is in the fulcrum, not the tip. Famed cam grinder Racer Brown showed that those tiny little rollers are too small to effect a mechanical couple with the valve stem tip anyway. They just skid across in most cases. I am of the opinion that the rocker arm manufacturers got it bass-ackwards. The best design, in my opinion, would be a roller fulcrum with a conventional tip. Racer Brown showed how they can be rolled on the valve stem tip without tearing a thin cigarette paper, so that crappy little roller on the tip is just a joke.


Not with your original plan. Start with your fuel choice and build from there.


I would use a plate system between the EFI and intake manifold. Building a 500 hp naturally aspirated motor with a 150 shot would make sense. Plan on forged pistons and increased clearances on bearings and rings.

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I appreciate the the input and I will be further looking into this build based on your suggestions, one thing I did want to say though, it may sound bogus but the block casting number is 330817 which is a 70s-80s 400CID small block chevy, the number on the heads, manifold, and tbi all come back to a emissions 305 sbc.

Originally Posted by garrett3698

I appreciate the the input and I will be further looking into this build based on your suggestions, one thing I did want to say though, it may sound bogus but the block casting number is 330817 which is a 70s-80s 400CID small block chevy, the number on the heads, manifold, and tbi all come back to a emissions 305 sbc.

It just seemed unusual that someone would pull the motor, begin the build with a 400 block and then crutch it down with emissions 305 junk. I guess there's no accounting for common sense. Maybe the fellows down at the Sonic Drive In told him that was the hot tip. Carry on.....

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Originally Posted by techinspector1

It just seemed unusual that someone would pull the motor, begin the build with a 400 block and then crutch it down with emissions 305 junk. I guess there's no accounting for common sense. Maybe the fellows down at the Sonic Drive In told him that was the hot tip. Carry on.....

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Exactly my point, it has so much potential, but they choked the performance in the worst way.