[Littlered wagon]

Anybody built a 400 sbc lately would like some good pointers on this build.I allready have flat top Wiseco pistons & 4340 5.7 H beam rods plus a 284 crane hyd.roller cam any thoughts

[poncho62]

My thought is, that tis belongs in the engine forum, so I am moving it.....................and welcome.

[BOBCRMAN@aol.com]

The secret is good cylinder heads!! Aftermkt. Good flow numbers.

[Littlered wagon]

Oops rookie computer user

[NAIRB]

It is going to really depend upon what you want to do with the engine and how much you want to spend.

Is it a street engine? Will it burn pump fuel? What are your budget concerns? What kind of vehicle are you going to put it in?

[Mad Maggot]

With that cam, take a set of AFR 195cc heads, an Edelbrock RPM Air Gap manifold, a 750cfm carburetor and a good exhaust system with headers and you should be well on your way.

[OddRodder]

I would go with Dart Iron Eagles (200cc). On the street, with premium fuel, you should be able to run close to 10to1 compression with flat tops and a tight quench (around .040) without detonation problems.

[Mad Maggot]

I don't know about the Iron Eagles... they don't really flow all that well. You would be challenged to make 500 HP with a set of those heads, unless you use a very aggressive solid roller cam. Chevy Hi Performance Magazine did a flow bench comparison of all the major heads, and the Iron Eagles were quite short on the numbers.

http://chevyhiperformance.com/techarticles/41598/

A good rule of thumb is with roller cams, you generally multiply the .500 valve lift flow number by two to get a horsepower estimate. For 500 HP you will need a 250cfm head.

[bracketeer]

Dart Iron Eagles (200cc). On the street, with premium fuel, you should be able to run close to 10to1 compression with flat tops

He said 400 not 350.
64 cc 11.2 to 1
70 cc 10.8 to 1
72 cc 10.6 to 1
stock head 10.2 to 1

[firestone]

I agree with the AFR 195's. Anything less, and you will be really hard pressed to get 500 hp.

Adam

[NAIRB]

You will be hard pressed to make 500 horsepower period with pump fuels. I know everyone is going to argue the point, but I would think 450 horsepower is going to be more realistic.

A top engine builder could do it, but it would take alot of intricate work to extract that much power out of it without bumping the compression up considerably or using a touch of nitrous.

I would probably use a compression ratio of 9.5:1 (true), a set of fully ported Vortec iron heads, a healthy hydraulic roller or flat lifter cam (108 lsa, .520 lift range, and about 235 deg duration @.050 with a little extra on the exhaust side.) Either a Performer RPM or Victor Jr, and minimum 750 Holley type carb. Cam specs given here are ballpark.

I would arm it with a very small nitrous kit to achieve the 500 horsepower mark.

An engine like the one listed above would be very streetable, make good torque, and run on pump fuel, and would be economical to build.

That's how I would do it, but there are other ways, depending upon your tastes and wallet size.

[lluciano77]

500 is easy on pump gas. All it takes is 9.5:1 or higher compression, a good set of heads, a good cam, and all the bolt-ons. 400s put out a lot of power and torque. A lot more than a similarly built 350.

The 400 kind of reminds me of my 5.0. They are both pretty restricted from the factory. All it takes is a little more breathing and they wake up fast.

[NAIRB]

Originally posted by lluciano77
500 is easy on pump gas. All it takes is 9.5:1 or higher compression, a good set of heads, a good cam, and all the bolt-ons. 400s put out a lot of power and torque. A lot more than a similarly built 350.

The 400 kind of reminds me of my 5.0. They are both pretty restricted from the factory. All it takes is a little more breathing and they wake up fast.

I'll disagree with you. It's not just a matter of slapping a bunch of parts together to get that kind of power. At least the dyno I've used never saw those kind of power levels on street 400's.

Most circle track engines I've built (and I'm talking about 11.5:1-12.0:1 compression, a baseline Comp 285B-6 race cam, World 200 Sportsman heads and tricked up carb usually made around 450 real horsepower. Maybe our dyno was too conservative (Stuska), but I think that horsepower numbers are thrown around these days quite arbitrarily. Too many pie in the sky desktop dyno numbers or inflated magazine articles out there in my opinion.

500 is not super easy to get on a STREETABLE 400 small block. I'm not saying you can't do it, but you won't do it really cheap and you'll have to really tweak it and work with it.

If you have spent any time around a race shop with a dyno, you would figure that one out in a real hurry. I've seen many "powerful" engines disappoint their owners. I think it's a product of hype when it comes to quoted power figures.

Take into accouunt that the factory street hemi with mega-flow heads, solid cam, 10.25:1 compression and two four barrells only produced an actual 475 horsepower, or the LS-6 454 spewed out an actual 450 horsepower.
(pretty accurate numbers), I've dynoed some muscle car engines for muscle car drags, and can attest that those numbers were pretty accurate. A 400 small block is not quite the foundation of a hemi or rectangular port 454.

I'm not trying to be argumentative here, but I see all of this talk like it's easy to do it, when it's not quite that easy.

It's going to disappoint some novice engine builders when they barely make 400 ponies and they thought they woud make an easy 500.

[OddRodder]

Still need to know what littlered wagon plans to use this engine for? The easied way to accomplish the goal of 500h.p. is as NAIRB suggested, with a mild engine and a small shot of N.O.S. But, if you want to make an honest 500+ h.p. with motor only, this is a good article to duplicate!

http://chevyhiperformance.com/techarticles/90719/

I agree that dyno results are sometimes confusing, different numbers from different machines, throw in chassis dyno's that measure the rear wheel h.p. and things get even more confusing!

[Mad Maggot]

I agree with NAIRB that making 500 streetable horsepower is difficult, but with a 400 SBC, a big roller cam and some great flowing heads should get the job done. Of course, it may require a high stall and maybe a vacuum pump for the accessories, but it will still remain streetable. When building a monster motor like this, you can't skimp on anything and you'd better be prepared to shell out a lot more cash for it than you may think it would cost. Retro-fit roller cams are very expensive, as are the AFR heads.