Which chevy block to start with?
I want to build a 525 - 550 hp small block chevy for my '87 Camaro. My background is in building Pontiac engines and this is my first small block chevy. I need to keep the total cost of the engine under $6000. $1500 of that will go to AFR 195 or 210 heads. I have researched David Vizards "building affordable chevy small blocks" and want to copy a 406 that he built to 530 hp. I have the option of buying a 509 2-bolt 400 block, a new goodwrench 350 4-bolt main block, or a 3970010 4-bolt 350 block.
David Vizard says that properly prepped and sonic tested 400 2-bolts can handle up to 550 hp. Others on this forum say it's a 50/50 risk to try that.
I have read that the mexican goodwrench 350 4-bolt blocks are very strong and can take a 4.125/4.155 bore as long as there is no core shift, sonic tested walls of .25 or higher, and with block filler.
I have also read that the 1973 - 1982 3970010 10/20 blocks are also very strong and can take a 4.155/4.185 bore as long as there is no core shift, sonic tested walls of .25 or higher, and with block filler.
I have access to any/all of the above blocks. Which one should I choose? Any suggestions?
The 010/020 blocks are a bit of an urban legend. They exist in plentiful numbers, but whether or not they actually contain the extra nickel and tin in the alloy is questionable. Rumor has it that they used the same molds to cast all different alloys. Also, don't confuse the "010" casting number with an 010 alloy. The casting number doesn't necessarily mean that its a high nickel alloy. Look at the sides of the block and you should see 010 cast by itself if its one of those high nickel blocks.
Having said that... I don't like the idea of the extra nickel for a high rpm/high hp application. Harder is not stronger and in fact harder in this case means more brittle. Softer castings can absorb more impact and harmonic frequencies than hard stuff. Its the same reason people use forged pistons instead of cast. Cast pistons are brittle and can break under stress. Forged pistons are malleable and can deform and absorb stresses. Hard blocks are great in trucks, torque applications, and places where longevity takes priority over RPM.
There is also some debate about 2- versus 4-bolt mains. The 2-bolt blocks have beefier webbing at the mains, so many agree that the strongest bottom end is a 2-bolt block machined for splayed 4-bolt mains.
So, what I would personally do is choose an older 2-bolt block with a known thicker casting and have it machined for 4-bolts.
I would also suggest a 383, but its only a light suggestion. They don't have as much displacement, but its easier to find a thick-cast 350 block than it is a 400 block. I'd feel a little better about laying hard into a 383 than a 400, but like I said, people run 400 blocks to 500 hp all the time, it just might take a little more money to do it with peace of mind.
Here's a dyno combo from Air Flow Research. Call up AFR while you're ordering the heads and get the details on this build. By the way, have them drill for the steam holes before they ship them to you.
RPM Torque H.P.
2500 463 220
3000 468 267
3500 457 304
4000 465 354
4500 534 457
5000 540 514
5500 510 534
6000 483 551
Horsepower: 550 hp street motor
Engine: 406 SBC
Heads: AFR CNC Race Ready 210cc
Ignition: MSD HEI Billet, 36* timing
Cam: Lunati Hyd. Roller 232*/242*, 0.560"/0.570", 1.6 rockers
Exhaust: 1 3/4" headers
Fuel: 93 octane pump gas
I'm also bettin' that if you tightened up the squish to 0.035" to 0.040", you could run less octane than the 93.
I will talk with AFR about that buildup. That's actually perfect.
I actually have the opportunity to choose thru 3 different 509 2-bolt blocks, so maybe I should buy two of the blocks just in case one doesn't sonic check very well.
I see that Speedomotive uses the 350 splayed goodwrench block for their 500 - 550 hp crate motors.
Octane FYI - here in Washington, my buddy who owns a Chevron said that the new 89 mid grade mixes 50/50 with 87 unleaded to make 97 octane, and that they're not supposed to "knowingly" let anybody mix it as it exceeds state gas octane regulations. So I will target 10.8 - 1 comp. with the AFR heads. My wife's Mazda minivan has 10 - 1 with aluminum heads and it runs great on 87 octane.
We machine a lot of 350 blocks and so far we have seen none of them that will bore to 4.125 or 4.155 bore.
I have had more calls on broken 400 blocks over the years then the 350 blocks and at 550 horse your flirting with disaster.
Dart has a new SHP block that is only ratred at 600 horse and its 10 times the block a 400 is and its good for 550 horse HMMMM
Here is a link to the SHP block
I found some details. Price is $1400. This is basically the same cost as buying the two used blocks and having all the machine work done. Thanks CNC NE! I knew you would add some valuable advice.
Dart Special High Performance (SHP) Small Block Chevy Iron Block
Why waste your valuable time sourcing, cleaning, machining and prepping a 30 year old small block core in the hope it will be usable?
What if you could have a true high performance small block from the most respected aftermarket block manufacturer without the expense of a full race block? Now you can...
The new Special High Performance Small Block Chevy block from Dart gives you all the features you need to build a powerful and durable engine at an affordable price. Cast from high nickel iron for superior strength, the SHP block features siamese cylinders with 4.000 or 4.125 standard bore sizes available. Cylinder walls are a minimum of .230" thick at 4.165 bore!
The block is machined using precision digital CNC equipment and is virtually ready to assemble right out of the box after a final cylinder hone. Decks are even and parallel within .002", lifter bores, cam and main tunnels are finished. The Dart SHP block is designed for compatibility with stock components, so no costly special parts are required for assembly.
* Made in the USA
* Brand new precision machined block
* Premium high strength cast iron
* Priority main oiling system
* Siamese bores 4.000 or 4.125 (unfinished)
* At 4.165 bore cylinder walls are .230" thick
* Clearance for 3.75" stroke crank w/steel rods
* Decks are even and parallel within .002"
* Blind head bolt holes
* 350 main journals
* Splayed 4 bolt center three main caps
* Two piece rear main seal
* Provisions for OE stock roller lifters and cams
* Uses 1981 - 1985 stock style oil pan and dipstick
* Uses stock stamped steel or plastic timing cover
* All OE bolt holes for starter, clutch ball, etc.
Also available as a ready to assemble package from Lukovich Racing Engines with finish honing, with complete or partial rotating assembly, or in assembled short block and long block combinations.
Dart SHP Small Block Specifications
Part #: 3116111 4.000" Bore / 31161211 4.125" Bore
Material: Superior Iron Alloy
Bore: 4.000" or 4.125" unfinished
Bore & Stroke: 4.165" x 3.750" max recommended
Cam bearing bore ID: SBC 2.00"
Cam Bearing O.S. : +.010", .+.020, +.030"
Cam Bearing Press: .002"
Cam Journal OD: Standard SBC 1.869"
Cam Plug: 2 7/64" Shallow Cup
Cylinder Wall Thickness: .230" min.@ 4.165" bore
Deck Height: 9.025"
Deck Thickness: .625" min.
Fuel Pump: Mechanical Pump Provision
Fuel Pump Pushrod: Standard Length
Freeze Plugs: Press in cup plugs - 1 5/8"
Lifter Bores: SBC .8430" - .8440"
Main Bearing Size: 2.450" (350)
Main Bearing Bore: (350) 2.6405" - 2.6415"
Main Cap Bolts: #1 7/16" (2), #2-3-4 7/16" (2) 3/8 Splayed (2), #5 7/16" (2)
Main Cap Press: .005"
Main Cap Register: Deep Steeped register on each side (no need for dowels)
Oil System: Wet Sump, Priority Oiling (can use dry sump)
Oil Pump Shaft: 350 Main = Stock Shaft (.481" OD)
Oil FIlter: Standard SBC filter, uses 2 bolt filter adapter
Oil Pan: Standard SBC Pan
Rear Main Seal: 350 Main, std seal 2 pc
Serial Number: Left Front and Main Caps
Starter: Standard SBC
Stud Holes, Head: Blind Holes
Timing Chain/Gears: Standard SBC Components
Timing Cover: Can use stock cover / Stamped Steel or Plastic
Torque Specs: 7/16" Bolts - 65 ft lbs
3/8" Bolts - 35 ft lbs
Weight: 175 lbs @ 4.00 bore
pick the correct block!
I have a chevy small block that produces 550hp and it displaces 388 cubes Do your homework on the block and at that level strongly consider an aftermarket like the Dart SHP or I could recommend a GM perf block like I bought. My oem 350 block bit the dust with only a .060 overbore and was a 1979 010/020 block. The max most will advise from a machinists view will be .040-.060 overbore if they sonic test ok. I spun my motor to 7500rpm all the time and the block eventually suffered leaving me with a lot of blue smoke out of the pipes. I have a gm perf block that is new it has 1pc rear main 2 bolt that I splayed the caps and had it bored and shipped for under 1700.00! The catch here is this block comes rough bore @ 3.990 so it is bore to your specs but all else is done. This block will SAFELY go to 4.155bore but it has 350 main size. so you could make a 350 355 357 360 ... 400 406 415 421 434? It is machined to clear a 3.75 stroke but the machine shop told me that it could be clearanced for possibly a 4.00 stroke! The minimun cylinder thickness measured at 4.155 is .250" ! plenty of meat. I am in the process of this buildup staying with the 388" so I have a lot of rebuilds left with this block. If you are interested in this block I can get you the info or just search on ebay for White Performance this is where it came from.
As stated , you will be wise to go with the dart block. Also go with the AFR 210 the new version (as of 2008) uses the 8mm valves. I recently put together a 550 hp 400 and in retrospect I am sorry I did not use the dart block. After all the machine on a oem block you soon get close to the cost of the Dart block. You can keep the compression closer to 10:1 ; still make 550hp on pump gas. You may want to look at more duration to damper the compression. Comp Cams mechanical roller 248 / 254 with about .58 lift works well in a 400.
Just a note: When ordering your AFR 210s, have the folks a afr change the springs to their "street roller springs", the springs that come with the 210s are about 210 seat lbs. and some where near 600 open! - way too much for your application.
Last edited by 406 bug; 01-18-2009 at 10:44 PM.
Here some more food for thought. Have you upgraded the suspension in Camaro? The torque arm and panhard bar is stamped steel and flexes under stock power levels. Frame connectors are a must as well and if you door hinges are sloppy they need to be fixed. The doors are an integral part of stiffening the f-bodies. Its a shame to make all that power and not be able to put it to the ground.
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