Small Block & Big Block Chevy Specific - 350hp 406 sbc

A guy has a 406 sbc that has been rebuilt with a stock cam. My question is what would it take for that engine to make 350-400hp with a set of vortec heads. What size cam would you guys think i should use. Any replies would be greatly appreciated. Thanks

400 hp will be a walk in the park with a set of vortecs.i'd say get the comp cam xer hydraulic with .477/.480 lift with a performer air gap intake and a good 650-750 carb and it will make well over 400 on it's worst day.

Will the 268h give me a noticeable idle in the 406 or do i need to use the 274h, cuz that's what i want.

i would go with the 274.with the vortecs and a good dual plane and headers you will still have plenty of low end torque.

I have another question that i forgot to mention earlier. He said the pistons are speed pro .100. I asked him what would the compression be with a set of vortecs and he said with 64cc heads 11 to 1 and 68cc heads 10 to 1. Does any of this sound correct to you guys?

with a flat top piston a 406 will usually have compression between 11:0-11:6 with a 64 cc head.if they are .100 dished i'd say around 10:00 or so and 12:5 to 13:0 domed.hopefully they are not domes because that compression is too much for a steel-headed pump gas motor,spark knock would be terrible and your motor would probably not last long at all.

I was thinking the same about the compression being 12:1 or 13:1 also. Instead of vortecs i would have to use a set of 76cc heads. Will i still be able to acheive my goal with 76cc heads and the 274h cam?

274h on a 406 won't be bad at all.. I ran a 274h on a 355 for a while, then went to a 284h.. 284h idled like shit, 274h was very streetable.. 274h on a 406 should be cake. 268h is too small, and will have like a 5600-5800 redline probably in a 406, if that.. not to mention very tame sound. 274h at least.

Peace,
Josh

do you already have a set of 76cc heads?if they are factory heads your numbers will be much lower.

No, i don't have a set a 76cc or vortecs yet. So you think i would be able to use the 284h w/o using a canister?

Making power out of a 406 is a cakewalk. As for the cam..if you really wanna make some power go ahead and buy the retrofit roller kit. I run a 406 (see sig) that put down 514hp/564tq at the wheels. If you want to stay with a flat tappet ive had good luck with the Comp Magnum series 280 (280/280 .480/.480) and a 2500 stall. If you want some more details about a buildup i can help...just shoot me a messege.

i have a .259/.267 @.050 on a 108/104 in my 406 and i don't run a canister.i have never had brake problems,even when idling at 1000 rpms.

Ok, i decided not to get the vortec heads but get a set of AFR 195. The pistons are .100 dome and the midwest motorsports catalog says the compression will be 10.7 with 76cc heads. My question now is will the compression be too high for pump gas because the AFR's are 74 cc heads, therefore; raising the compression a little higher.

with a decent sized cam you will be ok. you may to have to mess with your weights if you are going to use an hei distributor but your compression should be o.k.what are you putting this motor in?

I'm putting this in a '86 Buick Regal daily driver.

So now I've decided on the following for certain: 274h cam kit, performer rpm intake, 670 holley street avenger, afr 195s. I'm gonna have thes pistons changed so I'll have 10.1-3. compression. Any more suggestions? I plan using a 700r4 trans. too. What gear ratio I should run with this tranny to take advantage of this cam with this being a daily driver?

If the car is heavy I'd try to stay around 3.73's if at all possible. However, your stall is gonna matter more than the gears.. but that cam is going to be very streetable on a 406.. that's for sure.. In a 350 I shifted at 6200 and had the idle up on a 6 speed around 850, and it was great. It made 338rwhp on shorty headers with a messed up holley carb.. a/f was completely screwed.. I ran afr 190's with mild porting.. flowed like 260cfm.. I think the combo your talking about is good for an honest 425-450 flywheel horsepower at a very low peak due to cubes.. and I think you'll be very happy with the setup.

Peace,
Josh

Comp. suggests a 2200 stall for that cam. Do yall think this engine will hold on on the stock crank and rods?

Yeah, should handle very well. Would still recommend a little larger cam especially with those heads. 280 or even 292 dur cam aint a problem on the street in those motors.

The 274h won't give me the slight lope I'm looking for in this engine? How do you think the street manners would be with the the 284h in it?

274h will very very slightly lope on a 406, but a 284h will have a nice lope. FWIW: I think the 284h would be best myself.. it was pretty good on my 350, but it was just a tad too much with the gears I was running, so I went back to 274h for better low rpm response (3.23 gears with a t-56 was hell).

I wouldn't use a 2200 cam on anything.. use at least like a 2600-2800.

Peace,
Josh

I was looking at "How to Build Big Inch Small Blocks" and they built a 406 sbc with vortec heads and a lunati cam. The specs were 9.5 comp. ratio, air gap rpm intake, holley 750, 230/230 @ 50 and .455/.455 lift. cam and nothing else fancy. The engine made 427hp @5100 and 525 ft lbs @3700 rpm.

That cam is very similar to the Comp Cams Magnum 280 and is very good...has nice sounding idle and pulls very well in the mid range.

The 284h calls for atleast a 2800 stall. Wouldn't that cause slippage during highway crusing in the 700r4 with 3.73 gears. So would I be better off using a th350? What's so special about a 509 cast 400 block?

You wont really notice a slip if you get a good 10" or 9.5" converter. I run a 10" 3000 stall in my GN and you cant even tell while driving normally...until you stomp it real quick and it jumps to about 3300.

i had the 292 cam in my 406 a few years ago and never had a bit of problem with it.sounded good too.

ProblemZ, I have a 400 small block, bored .060 {don't recommend this, now I need an over bore so I'm out a luck}, AFR 195 heads {74cc, 2.05 intakes, 1.625 exhaust}, flat top pistons {believe my compression is around 9:75 to 1}, Crane cam {224/234 @ .050, 490 lift but 1:6 rockers so the lift is more}, RPM manafold, 850 double pumper, 1 3/4" headers. Put out 438 Hp @ 5250 & 499 Tq. @ 4000. {flywheel dyno, oviously}. Guy who built motor said it'd put out more Hp & probably not even lose any Tq. with a bigger cam.... I think the stall was around 2400-2600. 700R4 trans which blew up. It was the weak link...... Hope this helps ya.... bill

Does anybody have a video or sound clip of a Comp 274H cam in a 406?

I changed my mind and wanted to get the voodoo 268 cam (http://www.holley.com/60103.asp) until I got a cam rec. from Lazer cams with the specs.: advertised duration 270/275, @.050 220/225, lift 465/460, lobe separation 108 with 104 intake centerline. When i filled out the rec. card I used the voodoo 268 specs. and they told me that the cam they recommeded would pick my torque up alot. Any suggestions or comments?

The voodoo 268 is just too small I think. The comp cam xe274, like people have said, would be the lowest starting point and bigger wouldnt hurt. I have the 274 in my 355 and it has a noticeable idle and pulls great to 6000. I have a 3.73 gears and it peels into 2nd and barks 3rd. I dont know any hp specs but I say go bigger than 274 with a 406 and good heads. Get a 3000 stall, 3.73 gears and you will be good to go.

i have a 400 smal block and it has the double hump 194 heads headers 282 energizer crane cam edelbrock hirise intake a 750 edelbrock carb and i had the heads redone and all that i was wonderin about how much power it might have cuz i have it in a 72 chevelle and its been sittin so i never drive it all brand new motor parts but original bottom end

Personally, I think you'd be nuts to not at least upgrade to 5.7" rods. 6" rods are nice but not really necessary, but the short rods in a 400 just have to go.

I have a 400 from a 20 year ago build, and this was not possible back then. It came out of the car last week for this reason.

Who said I wasn't using 5.7 rods?? Anyway, I decided to get a retro-fit kit for my setup. It's gonna be a daily driver so I got a custom cam from Comp on a small base circle ground close to the specs of the LT4 hot cam with a lilttle difference. The specs are 218/226@.050 and .528/.536 lift w/1.6 rockers. I think that would be best when using a 700r4 with a 2500 stall and a 3.42 rear.

One thing you will want to think about is whether you will use a lock-up converter or not with the 342 gear and a big cam. I had a 383 with a 238 -242 @ .050, 540 lift camshaft with a 700r4 and 373 gears. It was not the best even though it sure sounded good.

With the 195's you do not need anything over .575 lift. to make good power. And a 230@ .050 camshaft will be fine.

2800 stall and no lower.