How do I build a 406 with 500+ hp
 

I know there are some of you out there who have experience with building 406's with over 500 hp with a lot of low end-to-middle torque. Please help me put mine together right.
My intent is to have a street-friendly engine with great pull up to maybe 6000 rpm's. Not interested (at this time) in going to the track so high mph isn't of major concern. Fitting under the stock hood would be nice.
What would be most helpful would be a list of specifics from air cleaner to oil pan of what you built yours with, anything you'd do differently if you were to do it again, and results - dyno testing results and /or satisfaction.
I know this is asking a lot but I'd GREATLY appreciate help.
Some of you 406er's I've been in contact with already and now I need to put together my parts list.
e-mails are welcome.
CDO

Re: How do I build a 406 with 500+ hp (CDOvette)
 

The key, in my opinion, is heads, cam & headers.

A 406 can handle the large valve (2.05 or 2.08) and large intake ports (215 cc) of an alum aftermarket head.

I like the Brodix Track I, you can run them out of the box or really get wild. I know a guy who is selling a set of ported, flowed, etc... But he wants $2K He really went the extra mile with these.

For a street friendly engine, use 9.5:1 or 10:1 so you can use pump gas.

High temp coatings on the piston crowns and on the chambers.

Call Ultradyne and buy a streetable hyd roller cam

Full length headers. I would buy the coated ones to help manage the heat. Then install a 2.5" exhaust.

I would also invest in a set of decent aftermarket rods. Don't have to spend $1200 for them, but something stronger than stock with good bolts.

EFI will make it very street friendly, but a carb can do the same if you tinker with it until it's right.

Stay away from the intake manifolds that are designed for 2500 to 6500 RPM. Get a good dual plane like the Edelbrock Performer. You want crisp throttle response and low end torque.

Finally, I wouldn't concentrate on just the 500 HP mark. A 406 with a mild roller cam and street heads / headers will make a very nice street engine. Build the engine right and then if you need a little more, spray it with a 150 hp shot.


[Modified by dsagers, 12:53 PM 8/28/2002]

Re: How do I build a 406 with 500+ hp (CDOvette)
 

A blower would help out... :jester

Actually forced induction is the way to go in my opinion for awsome horsepower and torque... and before that road trip... down size the pulley, cut some hp and gain some gas milage

The thing you have to fight, is friction, you want roller everything, solid roller cams, roller rockers, light weight valves... the cam grind is where you figure which side of 5252 rpm you want it to come together... to much duration... not much low end.

The other one you will need to focus on, is making the rest of the package run well... rear ends, u-joints, transmission parts.

With 500lbs and 500 hp, you'll want the low end to be built to handle anything... the rods, rod bolts, main caps, crank, bearings... they all have to be up to snuff... not the place to recover cash.

Solid engine mounts, accesorie mounts that can support the torque...

I cant tell you exact specs, but... you want the heads to flow well... but have a high velocity, you want to port and polish everything possible...

Pay attention to the details, crank scrapers, valley pans, carb spacers... they all help to increase power, dont forget these!

Good luck to you :cheers:

ZD

Re: How do I build a 406 with 500+ hp (CDOvette)
 

I built mine with:

2 bolt main block with studded main caps, ported oil passages, filled to bottom of front freeze plug with block fill, plugged the big holes in the deck and drilled to match head gasket, enlarged oil drain holes, decked, align honed, and bored .030" over.
Scat cast steel crank (internal balance designed for 6 inch rods), 6 inch eagle H-beam rods, Srp forged flat top pistons, AFR 210 heads (76cc cumbustion chambers which yielded 10.4:1 compression) and Champion 5 quart oil pan with trap door baffles and screen type windage tray. Oil pump is high volume/pressure. Edelbrock Victor water pump.
Weiand Team G 7530 single plane intake (fits under my stock hood with the Lt-1 aircleaner and 4 inch tall filter), Demon 750 double pumper, Hooker 1 3/4 headers with dual 3 inch exhaust. Crane hydrualic roller 284 cam (222/230 dur @.050), with comp cams pushrods, crane 1.6 roller rockers.

As built, this engine has 15 inches of vacuum at idle (actually idles better than a L-82 stock engine), uses premium pump gas with no detonation, is a pleasure to drive, and is quite fast (low 12's at 116+). It is in fact so mild, the only change I will make is a more agressive cam (see camshaft guru post in engine mods).

P.S. With the single plane intake I have plenty of low end torque. Even at the strip, traction is hard to control through first and most of second (m-20 4 speed with 3:73 gears and 255/16-50 Z-rated radial tires). In fourth gear I can lug the motor easily from 1000 rpm up. In fact, in most ordinary driving, I usually skip gears for less shifting!

:D


[Modified by 74vetteman, 3:22 PM 8/28/2002]

Re: How do I build a 406 with 500+ hp (74vetteman)
 

Thanks guys for your very helpful input!
This is my first project and I do want it to be a success. Dropped my two bolt 400 block off at the shop yesterday for cleaning, magging, checking deck alignment, etc. and bore .030". This is exciting! Wish I had the bucks to just build it now instead of gathering and progressing in stages.

dsagers - Is the high temp coating of the crowns and chambers an aftermarket service someone provides? Is this for NOS use? Any proven value in this for street use?

ZD75blue - As fun as it would be, a blower is not a consideration at this time. Maybe my next project! The bottom side of 5252 rpm's is where I'll be spending most of my time. The issue of "the rest of the package" is still grieving me. Think I'll start a thread for input on whether to build my 1980 4spd or find something else.

74vetteman - Sounds like you've built yourself a sweet package!
What does filling to the bottom of the front freeze plug do? I assume it reinforces a weak point of these blocks? What's the impact on cooling when on the street? A SBC 400 Scat series 9000, internally balanced, cast crank for 6" rods is what I've been looking at. And the hydraulic rollers seems to be the way to go. There are almost as many opinions on cams as there are on carbs. So what would be your choice for a more aggressive cam?

Ive gotta have things that have been proven to work so any more "tried-and true" success stories with specifics would be great!
Thanks again for all the help,
CO

Re: How do I build a 406 with 500+ hp (CDOvette)
 

I have seen several combinations out there.. If I would have an 500 HP 406 engine built - I would use following components:

Dart Pro 1 aluminum Heads with 230cc intake runners and 64cc chambers,
Forged SpeedPro Pistons approx. 10.5 - 10.8 : 1
Victor Jr. Intake (matched to gasket)
Comp Cams 306S solid cam!!!
Crane Gold Roller Rockers
Holley 80528 Carb

This combo should easily make 500+ HP!!!

Re: How do I build a 406 with 500+ hp (dsagers)
 

I agree with most everything with this post. You can go higher with the compression ratio, though. Remember, you can run up to 1 full point more compression with aluminum heads than you can/should with iron heads, assuming proper quench and cam. It's possible to have a pump gas-friendly 11:1 engine with aluminum heads.

I like 200-215 c.c. Dart Pro-1s, myself.

Give it a hydraulic roller cam in the 230-235 degree @ .050" duration and .510"-.520" lift neighborhood. Use a good dual-plane intake like a Weiand Stealth or Performer RPM. You ought to be OK with 1 5/8" full length headers and a 2.5" dual exhaust since you're really building torque. EFI is nice, but you can't hardly go wrong with a 750-800 CFM Holley. I like the mechanical secondary carbs even though the so-called "experts" say to use a vacuum secondary version on the street.

Keep in mind a 5,500-6,000 RPM target for peak horsepower and you will be able to have 500+ pounds of torque from idle all the way to 4,500 or so. Horsepower will take care of itself because it's nothing more than a measure of torque over time...

Tune it up and hang on, man.


[Modified by The Dude, 10:42 AM 8/29/2002]

Re: How do I build a 406 with 500+ hp (The Dude)
 

To run on reg 87 oct and save some $ use lower comp and alum heads. 9.5/1 will probably be :cool: with 87. If you are driving it a lot you will be happy to spend less $ without lossing much in hp/torq. If $ is not an issue then do the 11/1 and run premium.

Re: How do I build a 406 with 500+ hp (Fevre)
 

how about starting with a new block from GMPP?

Re: How do I build a 406 with 500+ hp (garagedweller2)
 

Actually, there is some advantage to using a "seasoned" block. It has been through many heat cycles, and has taken a set position and shouldn't move. Now I am not saying that a 2 bolt main 400 is better than a bow tie block, but for most street duty it is more than enough. The bow tie blocks actually share some architecture with the 400 blocks, such as siamesed bores, which contrary to popular belief makes the bores stronger and subject to less flex (as long as they meet minimum thickness).

I used block filler up to the bottom of my front freeze plugs to make the block even stronger and to support the bores better. It is supposedly worth a few hp. I thought for 20 bucks of filler it is cheap hp. The proper technique is to fill up to where you want (some drag only engines go almost to the top), then bolt on a head and let it sit overnight. Torquing the head similates the as built engine. Also have the main caps torqued on as well to simulate a running engine. After doing both sides (one per evening), have all your machining done.

Since most combustion heat is in the cylinder heads and very top of the bores, this will not affect cooling. For insurance I bought the best waterpump on the market (IMO the Edelbrock Victor) and haven't had the gauge go up to even 200 in all conditions. I am using the big block rad with stock fan.
Another benefit is that the block filler insulates the coolant from the oil. It is worth a few hp to have cool coolant and hotter oil.

Re: How do I build a 406 with 500+ hp (CDOvette)
 

406ci SBC
HP=550
Heads: AFR CNC Cyl Heads 210cc Race Ready
Compression: 10.3:1
Carb: 750 cfm
Ignition/Timing: MSD HEI Billet Distributor 36* Timing
Cam: Lunati Hyd. Roller Cams 232*/ 242+ .560-.570 lift w/ 1.6 rockers
Exhaust 1 3/4" Headers
Fuel: 93 octane pump gas

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

This combo is off of AFR's website and available from Ceralli Competition Engines. I have not built this combo, but looks to fit what your looking for :) . :cheers:

Re: How do I build a 406 with 500+ hp (SmokedTires)
 

I hope I'll be able tell you how to make 575 HP+ in a couple weeks. My heads will be back from the porter today, and they should be flowed this weekend or next week. Then, I'll get my cam cut and my carb from http://www.apdracing.com .

I have the block machined and ready to go. I also have everything I need to put it together including and Eagle internally balanced forged rotating assembly. I already have bought some Hooker Super Comps, CSI electric water pump, oil pan w/windage tray, etc...

A friend of mine built one very similar to mine that dynoed 575hp. It went 10.70s off the trailer in a 3400lb chevelle.

It's going to be a wicked ride!

Jay

hi all- im new to the forum and am currently in beginning stages of a 406 sbc build for my 1970 corvette. i am going with an eagle balanced bottom end rotating assembly, will be running , dart pro 1-215/72cc alum heads, torker 2 intake for hood clearance reasons and i so want to pull close to 6000 rpm as well, holley vac sec 750, msd dist, headers, 2.5' exh, will have an appx comp ratio of 9.9-1, and will likely be using a comp cams xe274 with 1.6 roller rockers. car has 3.36 gears and a cr m21 4 spd. wondering if anyone has a desk top dyno for this set up- i have found sim builds pushing 500 hp/500 ft lbs but would like to plug this build into one if anyone can help- be much appreciated! i know this type of question comes up a lot about the 406 build - im currently just not all that happy with my 355 sbc and want a bunch mor low end torque as well as a strong puller to 5800-6000 rpm. heard this cam will be a good middle ground choice, works well in the 355 but not enough bottom end for me and hate having to dump my clutch at 4000 rpm!

street friendly year round?
lots of FAST summer toys out there, but how are they fall and spring? Ok on a clear winter day down to say, 32F?
Do they pull out instantly without warmup, like any new car? So i need to know the real intended use of the car,(any long trips on the highway? and the final gear ratio. 3.08? Overdrive? or a "low mph cruise" 3.73 track screamer? And what tires put down 500 HP on the street? I need new tires and want to know too! So we need to know tire and wheel size.
using drag radials? MT's? Is yearly tire replacements in the budget? They won't last long w/500hp! :lol:

Drop the Eagle stuff, it is garbage noadays and cost me plenty to replace, go to Callies for a few extra bucks.

10.5:1 cr ratio, 215cc heads that flow at least 285cfm and a solid roller XR280R and you will be in the 500-550HP range with a torque curve that isn't really a curve more like a straight line, like 350 ft/lbs to the wheels just off idle :cheers:

I never get tired of the sound of this motor :lol:

A hundred different ways to do this but if your going over 500 HP and want bottom end power and streetability use AFR 195 eliminators. About 10 to 1 compression, Hydraulic roller with about 230-235 duration @ .050, 110-112 lsa and mid .500 lift. Air gap intake, 1 3/4 long tube headers, 2 1/2" low resriction exhaust and go forged and roller everything. This will pull from 2000 to 5500 RPM, flat torque curve, and be over 525 HP & TQ and be a durable, low maintenance combination.

consider a 3.875 stroker crank.get some AFR or the bigger dart heads as mentioned above are needed.get a victor jr intake ,port to match .and try different spacers on the dyno.you will need a roller cam ,the comp 280 roller should do it.look at a demon 750 carb.

:iagree:

This is pretty much exactly the combo I have in my 406. I also used an Eagle forged crank that is internally balanced, Eagle h-beam forged 5.7" rods, and SRP forged flat top pistons.

Pulls like a mofo freight train, yet is still very streetable.

The Eagle 4340 forged crank I bought wasn't straight and the big end of rods were egg shaped. You can get by with stuff but I don't comprise.

63 Mako sounds like the same combo I never believed on Ryans pages, wish someone would build it, you ain't getting 500/500 @ 5500RPM with those parts, sorry