|03-01-2006 03:58 PM|
Everything I read says to stay conservative with cam selection with vortec heads. In a 400 sbc RPM intake, 9.5-10.0 comp XE274, 750 carb You are well over 425 HP and 500 FPTQ.
And it doesn't need a ton of service and is dependable. In a 3000 to 3500 lb. car or truck the thing will scream.
Stay conservative with stall speed and rear gear selection.
|02-28-2006 08:07 PM|
|Pr0blumz||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. This cam might not sound like you want it though. I have been doing alot of research also because I'm about to have a 406 built with AFR heads and the xe284.|
|02-28-2006 06:01 PM|
What about the XE284? Crane be a better choice? What about the VooDOo series cams? Also Ive been looking at the CHP's 406 "The Impersonator" buildup and it uses a Lunati Bracket Master II cam 00010....Says
"They provide excellent power over a broad power band and give that lopey idle so many people like. Hydraulic; Lopey idle. Strong mid range torque and horsepower. Stall converter, headers, increased compression ratio and gearing needed."
Advertised Duration IN/EX: 292/292
Duration @.050 IN/EX: 230/230
Gross Valve Lift IN/EX: .480"/.480"
Lobe Sep Angle / Intake Ctr Line: 109/107
Valve Lash IN/EX: Hyd/Hyd
RPM Range: 2000-6000
Would this cam be a better choice?
BTW - that engine with stock vortec heads and that cam made470FTLBS@2300RPM - If i was to build to that engine closly, can I expect similar power at 4300 feet? In other words, what effect does altitude have on power?...how much loss?
|02-28-2006 10:32 AM|
i was leaning toward this one too... the XE274 is a nice cam, but in a 355 or 383 it sounds really nice. in a 400, it is rather mellow... the bigger the air pump the more air it will take. the crane 284 would probably be a better choice... the XE274 would probably be better suited in a 383.
|02-28-2006 08:40 AM|
The cam won`t have the same lope it has in a 350, 400`s swallow bigger cams somewhat. we were running a 234 244 duration cam in a 400 and it just had a noticeable lope. In some cases this acts as a advantage, if you get a race and don`t have to open the hood let the smoother idle work to your advantage, the old "hey it`s just a 350 with a little cam" works pretty good.
With Vortec heads it`ll have blow the tires off out of the hole power, but I`ve also seen first hand what one will do with 200cc runner heads and it was incredible, it came out of the hole like someone kicked it square in the a** and screamed throughout the rpm band, but then again, we used to take 1st place in the mud races often with a 400 that had a old set of ported camel hump heads, 400`s hump period with just minor mods. If you run vortecs, make sure you do everything you can to keep it cool, run vortecs hot one time and that`s it. And I`m sure you`ve already been reminded of the next 2 things but it needs repeating, if your running the stock 5.565 rods don`t get rev happy or they`ll come unglued, and make sure you have the steam holes drilled in the heads.
|02-28-2006 07:41 AM|
The XE274 and vortecs heads will be fine for a daily driver in a 400. The truck in my avatar was my daily driver with a 406, Crane 284 Energizer cam, S/R Torquer heads, 670 Avenger, Performer RPM intake and a 2200 stall. Gas mileage was around 10 with 3.08's and 31" tires. It had a little more lope than the 268 cam that in the 350 when I first got the truck. Now that the truck has been more modified due to the need for horsepower along with 35's, it does not get driven that much on the street due to having to run a mix of pump gas and racing fuel. If you plan on hopping up in the future like most of us do, you might look at a set of 200cc heads. The 400's will easily take this size of runner without losing much torque.
As for the gears, I had both 3.42's with a t350 in a stock 81 Camaro Z with a 255/60 rear and 3.73 with a t-10 in a mildly-modified 78 Camaro Z with a 255/60 rear. Even though it has been ages ago, both were daily drivers while in Colorado making trips to the homeplace in Kansas. Gas mileage was very similar in both taking right at 2 tanks to get from Colorado Springs to Seneca (8 hr trip). Even though you are not planning on making many freeway miles, I would still go with the 3.42's. If you have a 350, I'd go with the 3.73's. The added torque of the 400 will make up the difference in the gearsets while keeping the revs lower just in case you go on the highway to help the 400 live longer.
|02-27-2006 09:31 PM|
Is 2500 or so stall with 3.73s liveable for daily driving? (to school and back...just a small radias around house) not very much freeway drving.
Also I would love to get 3.55 gears, but my axe is 10 bolt 8.5, and the only ratios that are availible it seems are 3.42s or jump up 3.70s(for the range i want) I cant find 3.50 or 3.55 for a 10bolt 8.5???
|02-27-2006 11:14 AM|
The vortec heads along with the XE274H on a 400 should be a great combo. The 3.73 gears will be a good choice if you are going to be driving primarily in the city. If you are going to be doing any highway driving, I would recommend 3.55's. This motor would make so much torque, that there would probably not be a huge difference between the two gear ratios as far as overall 1/4 mile times go. Here are a couple of articles to look at and compare yours to. Keep in mind that you will have to get the modified Vortec heads to run the XE274H cam. Scoggin Dickey offers nice Modified Vortec combos.
Modified Vortec heads:
383, but it still gives you an idea what a 406 would do
|02-27-2006 09:03 AM|
I have the 274 in my 355 w/vortec heads 10.3 cp. the thing screams and sounds nasty.
|02-26-2006 09:05 PM|
I think you are on the right track. I think the xe274 would be a great choice. To me the cam in the impala sounds a little bigger than the xe274 but if it is it should be a little more choppy in a small block, and still make excellet power. I would probably go 3.73 on the gears but it depends on tire size. As far as carb, if you can get a q-jet that is right go with it, if not go with a holley 750 or street avenger 670, but you either way you will be happier with vacuum secondaries.
I debated on the xe274 for my 383 but I am making 11.0:1 so I went with the 286h magnum. It sounds about like the impala clip.
|02-26-2006 08:39 PM|
XE274H cam sound like? Heads Choice? Help me decide on combo for chevy 400
Im having trouble choosing my cam...and heads. The engine is a chevy 400 which will be rebuilt - 9.5CR, 1 5/8 headers. The car (72 nova) will be driven everyday with some weekend track duty, with a TH350 trans with around 2500 stall and either 3.42 or probally 3.73 rear gear (is this overkill for daily driver?)
For top end it has to be either - ported 202 heads with weiand 8004 intake and qjet. Or vortec heads with air gap and 750 holley ???
For cam, its looking like I would like comps XE274H(from what Ive seen, this cam gives great power) Any other cam suggestions? Would this cam work good with the combos above? Is XE274 overkill for daily driver?
I would really love the car to sound like this - http://www.antechlabs.com/K0GFM/65Impala1.wmv That is a XE274H in a big block...with the xe274h in a small block 400, would it rumpity the same? or more?
Desktop dyno puts both combos with the XE274H at around 400HP@5000RPM and 430FTLBS@2000RPM with peak torque 455FTLBS@3500RPM -- My goal/ Id love to put 300 HP and ft lbs to the rear wheels...does this combo come even close? Considering Im at 4300 ft elevation? Do the DD numbers put me in that range?