how much would it cost (normally) to do a mild rebuild of a 400sb, i could get a rebuilable blcok for $250 what would be the total cost of a rebuild with decent pistons ( i would get new heads) just a ball park figure would be good, i would like to be able to run in the 12's with an engine like this (with TPI) what do you guys think and how much $ to accomplish that. Thanks

 

it depends on how much you want to spend.

i have priced out about 1200 dollars for a lowend scat forged crankshaft, and their lowerend 4140?? connecting rods, and keith black hypereuetic pistons. and some rings. but that is just ballpark.

as for the TPI... I myself, which is in the same boat as you, is looking at a LT1 intake modified for a small block for about 400 bucks. and that will work better than a TPI on a 400" small block.

as for heads, I am looking at skoggin dickeys catalog for some worked over "492" camel hump heads for.....469.95 each.
or
you can go Vortec style and put a set of those on for about 400 bucks or more.

throw in a decient cam and valvetrain. All of the brackets, pumps and stuff....and miscelaneous intake parts like injectors and stuff,

2000-2500 or something

but i may also be missing something.

andreww

 

oh and about where are you from?

i am just trying to figure out one of my 400 blocks may be worth. because i may want to sell one sometime if i needed the money

thanks

 

mid VA, i think i would go with the vortec heads and TPI intake from scoggin dickey, and some high flow runners, i dont want a fancy race engine, just something decent

 

no more opionions?

 

I've built a few of them.

THey are not really any more money than doing a 350 Chevy. You gotta make sure the crank journals are straight in the block and that the decks are flat (this is a known problem with a lot of 400s). Other than that the cost of a stock replacement 400 crank isn't much more than a 350 crank. Ditto pistons, rods, etc. That's why it's the poor man's big block.

From a bare block expect to spend maybe $1500 on a good quality low-buck rebuild of the bottom end depending on how much machine work the block requires.

 

sorry i posted it twice

 

I am also in the process of building a 406small block chevy(400 bored .30 over), heres a list of what ive got so far and how much it has cost me:
Keith Black Pistons-$245
Comp Cams 268 series kit- $280 ~kit includes timing chain, valve
springs, camshaft, retainers
Headers- $105 Hedman shorties
Gaskets- $50 Fel-pro
Oil Pump- $20 melling high volume
Bearings- $60 Clevite 77
Water pump-$40 new stock pump
connecting rods- $250 GM powdered 5.7 rods
Crank- Stock
Bore .30 over- $159
Valve covers- $35 Edelbrock Sig series
Oil Pan- Stock
Push rods- Stock
that list adds up to about $1300 but that is just your basic engine parts list. I already had carb, intake, crank, heads, oil pan, pushrods, and the block.

 

Power lives in the heads, especially in a big CID motor. Doesn't matter how big the jugs are if you can't fill and empty them quickly.

Get rid of the TPI for the same reason. Without serious $$$$ aftermarket parts, it will choke a 400; your power output will crater at about 4200 RPM. There are lots of cheaper better ways to make power, including several aftermarket fuel injection systems that do away with the long tube runners. On mine I have GM 186 heads and a Holley 800 carb. I recently built a bigger motor than a 400 for a friend, used the Accel Pro Ram, seemed to work fairly well.

Damon's estimate is about right, but is only for a basically stock bottom end. However if you stick with TPI, it will protect your bottom end from ever seeing enough stress to require anything else. Avoid a bunch of chrome and pointless gadgetry like timing gear drives and HV oil pumps; use a high-quality chain such as the better Comp one, and use a regular M55 pump with the Mr Gasket 26 spring for high pressure. Your piston choice will depend on what heads you get. Aim for about 9.5:1 compression if you get cast iron heads, or 10.5:1 with aluminum ones. Be careful with what rods you get, as it's real easy to end up with clearance problems, they can hit the block, oil pan or cam. The guy above that is using the GM PM rods, for example, will be spending many hours with a die grinder, and he may have to get a different cam as well.

 

Hey RB83L69- Why do you say that about the rods hitting? What rods can i get so they wont hit... if any? As i said i have comp cams Extreme Energy 268 Series. Would Scat rods clear? or what would you reccomend? I really dont want to have to grind anything.

 

He's correct about stock tpi, It will kill you're high end on that engine. I would go for a modified lt1 intake www.lt1intake.com You can pick one up for $400, then you will have to spend a little more on the fuel lines, and remote therm, and a 58mm TB. This thing will fead the 400 fine, and give you awesome hp numbers. Here is a graph of a similar setup(lt1, and miniram, make similar numbers)
406 Cubic Inches: L98 motor

Grimes 406, from Hi-Tech Performance December 1995

400 block, four bolt .030 over

Lunati forged 4340 steel crank 3.75"

Lunati Pro Mod 6" steel rods

Wiseco reverse-dome forged pistons

Chevrolet stage 6 heads, ported by Champion Racing, 62cc chambers, 10:1 comp, 2.02/1.60"

TPIS Miniram intake, 58mm throttle body

Lunati custom hydraulic roller cam, 232/232 @ .050, lift unknown, lobe sep unknown

RPM TQ HP
3600 452 310
3800 463 335
4000 469 357
4200 487 389
4400 496 416
4600 499 437
4800 503 460
5000 508 483
5200 499 494
5400 496 510
5600 489 521
5700 484 525
5800 471 520
5900 457 514

The combination of the large displacement, large heads, roller cam, and the intake system make good torque in a small block package. Using the Miniram instead of a SuperRam increases top end HP at the expense of torque lower down in the RPMs. Still, this motor is very strong, producing over 500 lbs of torque.

you could say hello to 11's wit this combo.

 

Those PM rods are of typical stock rod construction, with bolts & nuts. The head of the bolt, and maybe some of the shoulder of the rod right under the head of the bolt, will hit the block near the oil pan rail and/or at the bottom of the cylinders. Additionally, since the rods in even a stock 400 setup intrude into the "volume" of the cylinder described by the cam bearing journals, there is a strong possibility they will hit cam lobes as well.

Stock 400 rod bolts are shorter, with the rod forging made such that the head of the bolt is closer to the parting line; and the bolt head is bevelled on the outside for extra clearance. The PM rods use the the longer bolts without the bevel, typical of 350 or other non-400-specific rods.

The safest bet is to use a cap-screw design rod such as Eagle etc.; obviously there's no bolt head to worry about. Equally obviously, once you get into stuff like $500 a set rods, this is not a $1500 budget buildup any more.

The smartest way to plan a motor buildup is to settle on a reasonable goal, in terms of RPMs (for example, if you plan on retaining 2.73 or 3.23 type of gearing, a 7000 RPM motor is a mistake) and actual HP or ET. Use common sense, don't let the little head take over all the thinking for the big head. Avoid romantic-sounding exotic parts in the bottom end if they aren't necessary, as they will not produce one single additional HP, they are only used to provide longevity. You'll get alot farther on your $$$ if you spend your money on the heads and leave the bottom end as stock as possible within reason. A bone-stock 400 bottom end is good to around 400 HP as long as it doesn't spin past 6000 RPM. Learn to rebuild a stock motor and make it live before you tackle a specialty modified type of deal; read some of the "Oh s***" type posts on this BBS and learn something from them, let their mistakes and discoveries save you the trouble of making the same ones yourself.

Also, note that the big numbers in the above post came from a motor with lots of $$$ in the heads. If you use inferior heads, you won't even come close. And of course those numbers were attained in magazine world, with an unlimited budget and access to every imaginable resource; that isn't the real world of an ordinary hobbyist with a real job to depend on as their daily driver to work and back.

 

Allright.... ive been looking at some different rods now... what do you think about these eagle SIR lighweight rods they are 570 grams and have all ARP wav Lok 3/8 bolts. I can get them for $219.99, do you think these will give me enough clearance so i wont have to grind anything?

 

No. They are still a bolt & nut design. Look at their SRP rods.