I recently purchased a 400 Small Block Chevy off of my neighbor who had all the parts for it laying around except for the heads and up. I already have everything for the engine except for the heads and am new to buying heads so I really have no clue how to go about sizing up the right heads for the cam that I have. The cam that I have is a Lunati Voodoo cam, here is a link to the cam spec card, http://www.lunatipower.com/CamSpecCa...rtNumber=60104 I am looking to make good power with this engine I want to make at least 450 HP and would like to preferably get Edelbrock heads, also everything with the motor is after market except for the connecting rods, the engine is even bored .030. Thanks in advance for any help you can give me.

 

Edelbrock heads will be struggle to get that much power out of; that's not what they're made for. Good heads, don't get me wrong, just, not "the most" power. They're designed for good street manners, low-end torque, etc. Their intake runners are simply too small for "the most" power.

Look at heads in the 190 - 200 cc intake port range (the Eddies are about 170cc) from a top-line mfr. I'd suggest sticking with AFR, Dart, or possibly Canfield (you can get those cheeeeep, as Jeg's brand).

Before you finish building it, I would also offer, that of ALL the pieces of a stock 400 bottom end I would NOT use, it's the rods. Now I've only built a coupla dozen 400s in my day, so I'm no expert; but ... take it for what it's worth. Main reason being, the stock rods REQUIRE external balance, which multiplies the whole hassle factor ENORMOUSLY; besides being just generally weeeeek and weeeeeeenie.

Don't forget to have the inboard starter bolt hole drilled in the block BEFORE you drop the motor into the car, lest your next post be something about "my T-5 starter won't bolt up".

 

I wouldn't use Edelbrock heads if they were given to me. As mentioned above, there are much better heads to pick from.

There are so many factors into putting together the right components. Cam choice will determine powerband and power levels of the engine. Pistons will need to be chosen with enough valve reliefs to clear the valves when higher than stock lift is used. Head choice is one thing but how the valves are set up is determined by the cam grind. So many more factors involved in just that. Will the valve springs bind at full lift? Will the underside of the spring retainers hit the top of the valve guide or seal at full lift etc?

The 400 block is a good starting point providing it hasn't been bored out yet. A 0.030" overbore is all it can safely handle. Pistons are cast and are good for a street engine but any kind of performance build should use something better. The crankshaft is cast. Buying an aftermarket forged (steel) crank is stronger. The 400's rods are short and not that strong. Longer rods can be used if the proper pistons are also used to accommodate the longer rods. If you plan on using the stock rods, put in some new rod bolts.

So picking up a 400 that needs to be rebuilt sounds like a good deal until you piece it all together and find out it may be cheaper to buy a pre assembled engine from an engine builder that has all the work done and tolerances checked. Even a stock replacement engine will be cheaper.

 

So what do you think would be a good set of heads to get then? The thing is I have no clue as far as what to look for and what would work well with my set up. Here are the pistons that I have for the engine.http://www.summitracing.com/parts/stl-h400cp I have almost all the money I need to buy the heads and should be able to purchase them within a week and want to really get the best bang for my buck all I really need to know are what size heads I should look at and such.

 

I looked up dart heads on summit and theyre cheaper than edelbrock heads, anyway heres what I was looking at,http://www.summitracing.com/parts/dr...make/chevrolet it'd be amazing if you could take a look and tell me what you think.

 

Though the displacement is important, it is only one of many deciding factors in what heads to get. Tell us if you are married to having that cam, or if you would be going to a retro fit roller. what intake you are using, how the car is going to be driven, and what supporting mods you are going to install, and how many rpms you intend to spin. With that info, you can get some good suggestions.

Afr, or profiler 195s wouldn't be too bad. Possibly the 210cc, depending on intake and cam.

 

I have Dart race heads on my BBC but if I was going to build a SBC, Dart or AFR would be my first choice.

Aluminum heads are not the exotic option they were decades ago. Iron heads are very inexpensive and a set of good aluminum heads has become very affordable. Pick a set that will work with what you intend to do with the car.

Worst thing about Edelbrock heads is that they're more designed as a stock replacement than for good performance. Some Edelbrock heads when used with camshafts with lots of lift may require a special piston because Edelbrock makes their heads different from everyone else.

Since you're going to be using a large bore of a 400 block, go for a bigger valve in the head. 2.05/1.60 should fit with no problems and will help the larger displacement.

 

Don't exclude the possibility of using Brodix heads.They are a excellent head that are rated by the use of wet testing which is a more real world type port test for flow.

 

Has any one wondered or provin the mating of aluminum vers iron heads to a iron block? From what I understand aluminum expands more and faster than iron. Has or is this affect something to be of consern?

 

Yes the iron block has a different rate of thermal expansion than the aluminum head and this combo has been produced and sold straight from the factory for some years now. The proper head gasket helps with keeping the head sealed to the block.

 

GM has used Brodix to make some of there top end heads. They used to use winters foundry years ago and still may but a lot of the heads the nascar guys use are made from Brodix. I use track1 heads and a stealth ram both highly ported and it works great. It has good street manners and will wind past 7000RPM quick. AFR, Dart, Edelbrock and others are advertised a lot more but the serious dirt track guys and a lot of serious 1/4 mile guys use Brodix. But these days with CNC machines any company with a good engineer can make a good set of heads. It is a lot different than when I was a kid and a set of aluminum heads was rare. You actually make more power with cast iron.

 

To GTAdriver,

One thing you haven't posted is what compression ratio you hope to achieve. What fuel are you going to be using race gas, 87 or 93 octane, E85? What's your piston to deck height? What cc pistons are you running?

All of these must be considered when selecting your heads. If you have dished pistons, like what is in 305 motors it would be better and get different pistons rather than running a 58-52 cc head to achieve the proper static compression ratio for the cam you want to run.

Also running a 400 will require you to have steam holes in the heads. Not a big deal but something to consider that could be an added cost.