which heads for my 400 engine?

Hello there,

I wanted to get me new heads for my 74 400 engine. I already have a performer intake and a Thermoquad.
I also want to buy a Lunati Voodoo 10230701LK cam and hedman elite headers.

I wanted to buy edelbrock 5090 heads but read that they are not the best choice.
I want more compression with stock pistons. Everything is choosen for low RPM power.

I would buy a set of the sidewinder or 440 source heads.You can mill them a little to help with compression if need be.

the edelbrock 5090 would have 74 or 75 cc chambers. the sidewinder only has 84cc and the stealth 80 cc.
so for compression I think 74 or 75 cc would be good since I have a really low compression engine.

With a stock piston 400 it really doesn't matter what heads you run, compression is going to be low with no quench.

You'd be better off getting new pistons to fix the low compression rather than new heads at this point.

I know I won't see anything above 9,5:1.
I wanted to change the heads, because I wanted new valve springs etc. for the new cam.
So I thought I could get new heads straight away. So I'm searching some with a bit more compression for my stock pistons.
I don't want to change my pistons at this point because I think I gonna get me a stroker kit some time in the future.
It's a money thing and I want to drive my car this summer.
So it's either a stroker kit or cam, heads, headers etc.

I run the 84 cc Edelbrock heads. I have headers, rpm intake on a low compression motor. Gets my 3500 pound Volare to 12.4 in the 1/4.

If I were buying again I would get the sidewinder heads.

Also, I run a steel head gasket.

why would you choos the sidewinder next time?
and why did you choose the 84 cc instead of the 75 cc?

Any of the heads you are looking at will give you more flow, more power and less weight. I don't think compression differences will have a big effect with the current build.

Perhaps pick based on what would work best down the road when you go with the stroker. Run the compression numbers that way. A 3.75" stroke 451, for example, may work well with shelf flat top pistons and 80-84 cc's. Stroke longer than that will probably need a dish piston to dial in compression for pump gas with any of the choices.

I think you are on the right path. Not only would I purchase the 75 cc head, I would mill it to the desired compression ratio, or to the highest compression ratio with a reasonable cut on the head.

Giving up 10 cc on a low compression motor when you are already buying heads and doing the work just does not make sense.

Most people misunderstand what increasing CR does. There are formulas out there that that people use that generally show you the increase in peak power. These power increase numbers are modest and understate the actual result. Increased CR is one of the simple few things that you can do to increase the power from idle to red line. If you take an engine's power curve, and change nothing but engine's compression ratio, the entire power curve moves up. For the same change in peak horsepower, the CR change will result in more average hp increase.

Wow, what a coincidence. Look at this curve. If you follow how power curves change with typical performance upgrades, you will know that there usually isn't one change that can result in this kind of change in the area under the power curve.

https://board.moparts.org/ubbthreads/ubbt...tml#Post1821935

It will with any kind of a cam. low compression engine + high performance cam = crappy combo.

thanks for the infos guys.
the thing with low compression and a new cam is the reason, why I want to do the head swap together with the cam change.
The only problem is, that I read, that the 5090 e-street heads are no good.

is this a stock 400 with open chambered heads? How soon/serious are you about replacing it with the stroker? As said SCR is where you are hurting. you could mill the heck out of the open chambered heads or get a set of 516 iron closed chambered heads & home port em (tho you are in Germany/not sure what's available there) & as you know it would not be practical to ship some OE lo po iron heads. You could go with the alum heads with the smallest chambers & adv the oe stock (I'm assuming) cam 4 deg & dial in the dist subsystems then transplant the alum heads when the stroker comes together.

it'll take some time (2 years) until I stroke the engine.
I already bought new springs for dialing the distributor.
I wanted to get alu heads with small closed chambers (as you said for the shipping issues).
It's actually cheaper to buy them in the USA (even with shipment).
the whole plan (without stroking) is:
- mild cam (Lunati Voodoo 10230701L) mostly because I have the 2 bbl cam in
my engine but with a 4bbl carb.
- dialing the distributor
- tuning the carb (thermoquad; maybe buy a rebuilt one for high performance)
- new heads (which one?)
- new air cleaner for cold air intake (my car has a aftermarket open air
cleaner)
- a 3.2:1 gear set in the rear axle (maybe a bit later)
- new smaller wheels (I have huge ones now; 20" rims)
- hedman elite headers
- new spark plugs and all the small stuff

My suspension is already rebuilt.
The car should be technically good and fun to drive but a bit looking like a worn out car.

With a 74 400 on stock pistons you won't see anything NEAR 9.5 with a head change. Even with a set of 440 source heads milled down to 75cc you still won't see above 8.5 compression, likely closer to 8.0. Which is still better than your stock 7.5 of compression.

You can get a smogger 440 to perform decent, but your gains will be in:

Distributor tuning
carb tuning
exhaust
cam
torq converter
rear gear.

The cam you are choosing is very mild, a good choice for your compression and gear ratio. Your car will be a good cruiser but not a ground pounding, tire shredding machine. IMO if your stock heads are in ok shape, run them. Now if you were building for 1/4 mile performance, not highway cruising, I would go to a 4.10 gear, 3000rpm stall converter, move up a few steps in cam size, holley street dominator intake(will work with thermoquad), 440 source heads, headers, 3" dual exhaust and you could see some 12 second 1/4 mile times.

I thought stock compression is 8.2 : 1

I have a dual sidepipe exhaust with cherry bombs. The two pipes are not connected. Should they be connected?

It's good to hear that I am on the right way.
I don't want to go on a 1/4 mile but I want to get that 4000 pound ship moving. I'd like to have a really heavy car accelerating pretty fast. High speed is not the priority.
Would a 3.5:1 be a good compromise?
When I get a wilder cam I should use other heads right?

Would getting new heads be a super bad idea? I mean I would like to save money, but I also want to get a bit more power. But the engine runs really nice and I don't want to rip it apart completely

The 75 cc Eddy head mill to 70 cc will put him over 9:1. You could probably get to 9.5:1. Slapping on a 84 cc stealth head will be 8:1.

You can spend an additional $1000 to make another 30 or 40 hp with good heads, or spend $3000 on gears, converter, big exhaust, tire to make a turd feel better......

It doesn't have to be complicated. There are 10,000 different things you can do to make the 400 run better, but what you have chosen will make a substantial difference in your car. The 6090 heads were designed for exactly your purpose and the 10230701 cam will work fine in your engine. If you chose to go to a 3.55:1 gear the whole combination will make the car feel like a rocket ship vs what it is now.

When you learn from these few changes and later want to do the stroker, sell the heads and go to a more performance oriented cylinder head.

This is a quick example of what a 400 will do with less compression, cam and airflow than you are planning.

low compression 400 on the dyno

I'm impressed by those numbers from a 7.5:1 400! Now that's the perfect static CR to add a turbo

Remember the Direct Connection books (my '82 edition) had an 8:1 400 in a Duster and it ran deep into the 11's with 4.30 gears and the right converter, cam and intake combo.

I thank you guys for the informations. It helped me a lot.
Are there special head gasket i should use (thinner or better)?

I have a new question but don't want to open new threats every 5 days.
I hope somebody reads this.

I made a list with the parts I want to change/swap to make my newport faster.

For the heads and cam I want to take the engine out. When it is out I can change some other things. Should I get a lighter flexplate or something?
For the record: I want to have more torque and more acceleration. But more power in higher rpm's isn't a bad thing.

First of all there is nothing wrong with the less expensive Edelbrock heads for street use. You are not planning ultra high rpm or huge valvespring loads. They will flow plenty of air for a 400.
The stock compression ratio is a lie. Chrysler usually shipped their engines with between 1/2 and 1 point of compression less than advertised.

Using a Sealed Power piston compression height of 1.812", a stock 92cc head and a stock thin steel shim head gasket your compression calculates to 7.5:1.

Change to a 75cc Edelbrock 5090 and the same head gasket and your compression increases to 8.5:1. That is a significant increase. The compression ratio determines thermodynamic efficiency.

Stock head gaskets were steel shim, about 0.020" (0,5mm) thick. Many have used them with aluminum heads.

The LaRoy Engines advice is my thought, also. I would have picked the next larger camshaft, but it's hard to argue with the dyno numbers that they posted. It is very easy to put too much camshaft in a 383 or 400.

That camshaft seems to me to be a modern version of the stock HP engine camshaft. It will run with all stock valvegear in most cases.


The Lunati Voodoo cam line is very good. They use a 3-bolt cam drive gear, so you need to add a 3 bolt timing set to your list.

There isn't a lot of mass to take out of a flexplate, it isn't worth doing.

When you add headers, your carburetor will need to be adjusted. It is usual to have to increase carburetor jet size when adding headers. An air-fuel meter would help.

It helps power to have an H or X pipe system. The easiest is usually the H-pipe, which Mopar engineers used. The pipe connects both sides of the exhaust system and is usually installed where it fits best. The X-pipe adds complications and will require more work to install.

Your car will be more responsive with a high performance ignition curve. Stock curves brought spark advance in very slowly. High performance curves increase spark advance more quickly. You will also find that you get maximum power with total advance of 38 degrees, plus/minus a few. I understand the Firecore distributor, made by a Board member, has an ignition curve that's very easy to adjust. Stock distributors tend to have too much total advance and require much more work. There are other distributors with adjustable curves as well. Do not buy a no-name distributor on Ebay, or a Summit or Jeg's brand distributor.
R.

Paddel, maybe I missed it, but what model car is your 400 engine in? Just curious. How much does it weigh?

Okay thank you for your infos dogdays. I already did the distributor.
I want to add headers at last (maybe before converter change). I want to change my Thermoquad for a HP Thermoquad from a 440 and adjust it.

@D_C: it's a 1974 Newport. On the internet it is said to be around 4600 lbs.
I had to weigh it to register it but I don't know where the papers are.
But it's pretty heavy...

On paper. In real, no. See dogdays' post for some good info on this.

Yes, factory compression ratio can be a bit variable on a 40 year old production engine.

Lots of good advice so far. As suggested, total performance involves the entire car and sometimes you get greater performance improvements for money spent, from drivetrain and chassis components instead of focusing entirely on the engine, in getting the most performance for the money and effort expended.

Also, when you significantly improve engine performance, other parts of the car start to bend and break. Chassis twist, differential ring gears, u-joints, etc, break.

I went with Edelbrock Heads on my 440, but that was over ten years ago now. I have been happy with my choice, but as suggested, increased compression is like (relatively) free horsepower.

good advice. I already rebuilt my suspension.
I will change my third member with the new gear ratio (make al bearings new).
Maybe get a swaybar in the back.

I will also built subframe connectors (is that the right word). My dad and I are good in metalwork. I stiffened a Ford A 4 cylinder Frame to hold a 500 cui Cadillac Engine and it does not twist a bit and is still light (the car has 1200 kg).
I hope that the Alu heads reduce weight a bit (that I can feel it).
I don't know the right technical words but I lowered the car by screwing down the front suspension. So I put tension in it. It's bit hard to explain for me but I think you know what I mean. It's lower and harder.

The brakes work wonderful.
I thought about a alu drivetrain and third member. But that car will not make enough horsepower to notice (I think).

I write this all down to see if I am eading in the rigt direction, not to show ow smart I am

Thank you guys for your help

You'll wanna redo the dist when you get the eng running with the new swapped parts: heads/cam etc. Get the the mixture ballpark close then fine tune dist subsystems in order: initial/total/springs/can (if used) then fine tune the mixture with an LM1

You are doing fine. Those are the right things to be doing, such as subframe connectors and component upgrades.

About lowering the front end however, from all I have heard and read, lowering the front end by torsion bar adjustment...

A little bit is fine, but there is a point at which the suspension geometry is off, parts wear rapidly and it becomes difficult to maintain wheel alignment.

The Brodix B-1 B/S heads have 65cc chambers which would bump the compression up, but they do use an offset intake rocker arm. I'm still waiting to see the Trick Flow Power Port 240 Big block Mopar head?

The Brodix B-1 B/S heads have 65cc chambers which would bump the compression up, but they do use an offset intake rocker arm. I'm still waiting to see the Trick Flow Power Port 240 Big block Mopar head?

@D_C: that's right. I controlled that when I lowered the car.

So I'll go with that plan.

I just wanted to know another thing. Some people said, that I should use other pistons for some more compression. Are there any with just slip in and are usable with my stock parts (like crankshaft, conection rods...)

I thought that I should use new bearings and such and for that I have to take the engine apart. And when theres some money left I could use new pistons. But they have to work with the e-street heads and my stock parts.

But the pistons are not in the plan yet.

You are correct. The Firecore Distributor is extremely easy to dial in. We also have the last of the Mallory super-tune kits for the Mopar Distributors. Kit includes 9 springs, timing curve keys, and directions. I bought all that Summit had, FWI.

So long as you check with the piston manufacturer to verify, there should be Pistons that can be used with Original Equipment Factory components.

When you use aftermarket Pistons that increase compression, it is typically a good idea to check clearances to make sure that the valves are not going to hit the Pistons.

You may be able to use Modelling Clay to verify clearances.

You live far away and everything that you do should work right the first time. So I'm not in favor of anything that is too complicated.
Also, you are talking to a bunch of racers here and they will suggest race parts. For example, B1-BS heads are race heads and are not a true bolt-on. I don't believe they can use your stock rocker arms and pushrods. They also require a bit of machine work and setup, more than the Edelbrock heads. Forget them.

IF you are planning a stroker down the road don't buy a set of different 400 pistons at this point. Again, it's not worth it. Do whatever it takes to get to the next performance level and enjoy driving the car. I have projects that I got trapped in the "as long as I'm doing this..." syndrome. They are still not done after years and years. I do not recommend this approach for others, having learned the hard way myself. I have a garage full of parts that are now obsolete because of new improved designs. If I'd put them together when I bought them it would be okay. But now using them doesn't make sense. And nobody else wants them either.

I trust you can do all the structural work to the car yourself, or get it done. It is more fun to drive a car if it can go around a corner at speed. Same with stopping.

Your suggested engine modifications should increase power by 35% or so. That's noticeable.

Another thing, I doubt that you'll notice a difference between the large or the slightly larger Thermoquad. Both are large enough for your projected power level. If your carburetor works now, I'd suggest putting money into tuning it, rather than replacing it with another 30+ year old carburetor.

I have a wall full of carburetors and they are becoming less valuable as time goes by. A self-tuning fuel injection system is easier and better for 90% of the people who are still using carburetors.

Best Regards,
R.

Here's an example of a piston that'd replace a stock piston and increase compression while using all the other stock parts. The Keith Black KB240 has a compression height of 1.908 and will increase your compression ratio by nearly 2 points. It has huge valve notches which will swallow any extra lift you are planning. They are close to stock weight so no rebalancing required. Campbell Enterprises has them with new rings for around $520.00, but if adding pistons one really needs to bore to the next oversize which adds another $200 or more, plus cleaning the block, $100, plus pressing pins in and out which adds at least another $100.

So with the small chamber Edelbrocks you are looking at around 10.5:1 compression, will still run on pump Premium, but it will cost you at least another $900 plus shipping. This would be a really nice engine, and if you went that way I'd suggest the next larger Voodoo camshaft. You may not need to do anything else to the motor. It'd make an easy 440 or 450 hp.

Choices, choices.......

@dogdays: what you are saying makes really sense. and it's true. almost nobody here is an expert with those us cars.
the 10.5:1 compression sounds really nice and 450 hp would be more than enough.
But maybe, when I am done and drove the car a bit, I want even more.
It is really really hard to choose.
In the end it's a money thing. as always

Here are a couple of links that are related to your build. This shows the engine as I had it built and has a link to the original buildup. Short story, a simple steel 383 crank/ stock rod/ KB piston 9.7:1 shortblock with the smallest Comp Thumper cam. With stock 906 heads, RPM intake 750 Holley it made 427 HP 443 Ft/lbs. Mildly ported RPM heads 1.6:1 rockers Offy tunnel ram and a pair of AVS carb it made 472 hp 489 ft/lbs. Same basic build with a larger solid cam Victor heads bigger carb 1.7:1 rockers 507 HP 470 Ft/lbs. The compression was higher with the Victors due to the smaller chambers.

wow. those are really good numbers.
I am really looking forward to finishing the built.
Maybe I'll get the KB pistons. Seems they will add much more power.
When finished it will be a really smooth car.

I want to do the engine changes this winter.
with this parts:

-Edelbrock 5090 heads
-Lunati Voodoo 10230701LK cam
-keith black kb-240 pistons

and of course everything around (timing gears & chain, gaskets, pushrots....)

It was mentioned to use the 10230702 isntead of the 10230701 cam. But on the Lunati Homepage they say that the 10230702 needs improved valve springs. But I don't know if the springs on the Edelbrock 5090 heads can take it for long.

Also I maybe want to add an Edelbrock E-Street EFI because it automatically adujsts, I can set the fuel-gas-ratio for WOT etc., it will start even if it's really cold (it gets cold here) and just for the reliability.
But will that steal some Power or is it just plain stupid to do that?

Answering the last question first: It is just plain stupid NOT to use the EFI. Sure, a tuning maven might be able to tweak a carb for more power but I doubt you will have luck finding one on the Continent.

Board members who have made the switch are unanimous or nearly so that it was a good thing to do. If you can afford to do it, why not? And especially with European fuel prices.

On to the camshaft: The Edelbrock springs part number 5792 should be good for a hydraulic flat-tappet cam up to at least 0.600 lift. They are very close to the Lunati suggested spring for the 02 Voodoo cam, actually will have a higher spring load across the range from full open to closed. So there would be no reason to change the springs. I'd like the 01 camshaft better if you're doing a lot of stop and go driving, it'll have quite a bit more torque at low rpm, say until 2700rpm. After that the 02 cam may be better.

The 01 cam is quite similar to the 440HP camshaft, and that used to be the ticket for a 383, use the carb and cam from a 440HP_ engine in a 383.

In conclusion, the 383 is very easy to overcam and the good cylinder heads make it unnecessary to use such a big cam, so I'd stick with the 01 cam.

Think about the newest American V8s making really good power with camshafts that range from 197 to 211 degrees at 50 lift on the intake. That's because the heads flow so much better.

One more thing, the Voodoo cams are three-bolt cams meaning they need a 3-bolt timing set.

R.

Thank you very much for your answer. That's all I needed to know.

Just one more thing with the 5792 springs. Are those the springs which come with the 5090 heads or do I have to change them?

I have some stop and go driving, want the car to have low rpm torque and the 01 cam was my first choice until it was mentioned to use the 02 cam because of the higher compression rate (witch the heads and pistons).

Thank you very much

That information is taken directly from the Edelbrock catalog. It's kind of hard to find. I ended up getting it from the valve spring page, as it was not on the cylinder head page.

R.