Planning a 400 "B" Build

[MightyMats]

This is a long post.

I am sure this has been done somewhere before on the internet but I wanted to bounce some of my own ideas off you senior guys who have been around the block once or twice.

Goal: I want to build a bulletproof twin turbo 400 that will run on 93 Octane and not blow up

Horsepower Goal: Above 800hp/Close to 1000

Budget: 15k without machining. Or Turbos

I have been thinking about doing this build for awhile with a 440 but it just doesn't seem right. The heavier rotating assembly of the 440 coupled with a longer stroke doesn't really seem ideal for what I am shooting for here. The shorter stroke and lighter rotating assembly should help this thing rev more and the bearings will appreciate it.

I don't plan on stroking this block. It will need an overbore but thats the extent of the cubes I want to add to this.

71 400 block. $400

BCR's cap and girdle system. $800

4340 Forged Crank. $800

Lightweight rods: $600

Pistons: $800 + $150 for Rings

Chromoly pushrods: $130

Heads: $2500

ARP Head bolts $200

Intake: $400

Cam Gear Drive: $700

Cam Shaft + Hydraulic Rollers: $800

Distributor: $500 w/wires

Oil Pan: $300

Valve Covers: $150

Blow Through Carb: $600

Headers: $600-800 for materials (i'll build them)

Cam/Rod bearings: $300

All the misc I can't remember(valves, retainers, oil pump, fuel pump) : $1,000

Total: $11,930 (i'm probably under bidding this)


Here are some questions I would like to bounce off you guys. Since this is a turbo motor (my first) I don't need huge ported heads that flow 350+ CFM at .500 lift because the boost will help feed the engine the air it needs at higher RPM's right? Thoughts?

 

[Davea Lux]

Some things to consider:

1.) A flow gain is always a flow gain at all RPM ranges. You want the best heads and exhaust that you can manage.
2.) You need to calculate the amount of boost that you will need to get to the horse power you desire and a what RPM range. From there you can determine which rods, pistons and crankshafts are appropriate. The choice of camshafts will enter into this also. A light weight rod and crank kit may not hold together if you are running significant boost at high RPMs.
3.) If this is going to be a street machine, how are you going to cool it? A stock radiator is not going to cut it.
4.) It is entirely possible a twin turbo setup might need an inter cooler, depending on the boost rate.
5.) To do this right, this engine is going to need a fair amount of time on a dyno to get the fuel/air and boost ratios dialed in so that you new engine does not come apart or fry itself.
6.) You are significantly underestimating you costs. Probably something closer to $20k or more depending on how exotic you go.
7.) This is not a job you can do in your garage. Turbo engines are tricky to set up even for professional engine builders.

Dave

 

[MightyMats]

Some things to consider:

1.) A flow gain is always a flow gain at all RPM ranges. You want the best heads and exhaust that you can manage.
2.) You need to calculate the amount of boost that you will need to get to the horse power you desire and a what RPM range. From there you can determine which rods, pistons and crankshafts are appropriate. The choice of camshafts will enter into this also. A light weight rod and crank kit may not hold together if you are running significant boost at high RPMs.
3.) If this is going to be a street machine, how are you going to cool it? A stock radiator is not going to cut it.
4.) It is entirely possible a twin turbo setup might need an inter cooler, depending on the boost rate.
5.) To do this right, this engine is going to need a fair amount of time on a dyno to get the fuel/air and boost ratios dialed in so that you new engine does not come apart or fry itself.
6.) You are significantly underestimating you costs. Probably something closer to $20k or more depending on how exotic you go.
7.) This is not a job you can do in your garage. Turbo engines are tricky to set up even for professional engine builders.

Dave

I guess I need to start by figuring out how much power the engine will make N/a then start calculating how much power it will make with boost. I will have to talk to a builder who deals with this but im sure i don't want to have a CR higher than 8.5:1. This will probably get me going in the right direction.

I am currently running an aftermarket 2 core aluminum radiator with electric fans as well as a 10"x8" Derale oil cooler with a fan.

I was planning on running an air to air intercooler. I could make one fit in my C body (1967 Chrysler 300). I think I could fit both turbos under the hood if I modified the factory inner fenderwells. If I don't im sure they would have to play peak-a-boo out of the hood which I don't want to do.

Edit: thank you for your thoughts

 

[70bigblockdodge]

A couple of thoughts.
If your going to buy a aftermarket crank and rods why not add the cubic inches?
If you are at 500" and make 700 HP a single turbo blowing in like 10-12 psi would put you at the level you want to be at.
To make 700 horsepower you need airflow. Rule of thumb is CFM the intake port flows times 2 is the possible HP it can support.
Yes you can blow in 25+ psi of manifold pressure to get airflow numbers up but you are not doing that on gasoline, also very difficult to get a carburetor to be happy with inches of vacuum all the way to 30 psi manifold pressure.
At that HP level you are asking a lot from a stock block, yes the girdle will help, and 400 block is better for this. Your going to have to hardblock it.

 

[CBODY67]

You mention the rotating mass of the 440 vs a 400. Don' forget to look at piston weights! With and without the piston pins. Many Chrysler B/RB pistons are close to or over 1000 grams, which is HEAVY by themselves. The 440 will have heavier rods and more counterweight weight on the crank, BUT the counterweights can be shaved as needed with the lighter pistons (which might also reduce crankcase windage).

There's already been a build of what you propose, but in a '65 Belvedere body. A street car, too. I'll pm you his email address. It was in a Mopar magazine about 20 years ago.

The OTHER thing is what transmission do you propose to use? Driveshaft? Rear axle and other related suspension upgrades to put all of that power to the ground effectively?

Forced induction can be a good compensator for mediocre ports. Having a very unrestrictive exhaust can decrease the total amount of boost needed to achieve any goals of power. Sizing the turbo can be tricky. If all you want is power, then "bigger can be better", but with "turbo lag", whereas a smaller unit might cost some ultimate power, but be more responsive to the throttle with less turbo lag. Priorities, priorities, priorities . . .

Your car. Your dreams. Your $$$$. Just do it as good as you can.

Enjoy!
CBODY67

 

[MightyMats]

A couple of thoughts.
If your going to buy a aftermarket crank and rods why not add the cubic inches?
If you are at 500" and make 700 HP a single turbo blowing in like 10-12 psi would put you at the level you want to be at.
To make 700 horsepower you need airflow. Rule of thumb is CFM the intake port flows times 2 is the possible HP it can support.
Yes you can blow in 25+ psi of manifold pressure to get airflow numbers up but you are not doing that on gasoline, also very difficult to get a carburetor to be happy with inches of vacuum all the way to 30 psi manifold pressure.
At that HP level you are asking a lot from a stock block, yes the girdle will help, and 400 block is better for this. Your going to have to hardblock it.

My thoughts on not adding the cubic inches were to keep the rotating assembly lighter so it will rev more and really utilize the turbos and big roller cam. I also figured with some good parts I could get to my power level without having to add displacement.

I see what you are saying with airflow. The CNC'd edlebrock Victor Head has been tested to flow just over 350cfm at .500 of valve lift with is just about as good as I can get for my money.

I dont think I really need to be pushing over 15psi to achieve what I want. I am also not willing to hardblock the engine.

It's crazy that people are putting 5.7's on the dyno today and making over 1200 HP with twin turbos with stock cranks. Its really a testimate to how far technology has some. Here I am shaking in my boots with new main caps and a girdle wondering if I can make a block last. I should note that what i'm shooting for is nothing to scoff at.

 

[Turboomni]

Just curious ,you want all this power on 93 octane ,I understand but to do what and behave how?

 

[CBODY67]

One other thing to possibly consider. The 400 is "thin-wall" and usually .030" over is all you can bore them. Might be better to start with a 383 at +.030", due to the great wall thickness to start with? Or an earlier '70s 440?

Enjoy!
CBODY67

 

[MightyMats]

You mention the rotating mass of the 440 vs a 400. Don' forget to look at piston weights! With and without the piston pins. Many Chrysler B/RB pistons are close to or over 1000 grams, which is HEAVY by themselves. The 440 will have heavier rods and more counterweight weight on the crank, BUT the counterweights can be shaved as needed with the lighter pistons (which might also reduce crankcase windage).

There's already been a build of what you propose, but in a '65 Belvedere body. A street car, too. I'll pm you his email address. It was in a Mopar magazine about 20 years ago.

The OTHER thing is what transmission do you propose to use? Driveshaft? Rear axle and other related suspension upgrades to put all of that power to the ground effectively?

Forced induction can be a good compensator for mediocre ports. Having a very unrestrictive exhaust can decrease the total amount of boost needed to achieve any goals of power. Sizing the turbo can be tricky. If all you want is power, then "bigger can be better", but with "turbo lag", whereas a smaller unit might cost some ultimate power, but be more responsive to the throttle with less turbo lag. Priorities, priorities, priorities . . .

Your car. Your dreams. Your $$$$. Just do it as good as you can.

Enjoy!
CBODY67

I was thinking of using a 727 for a transmission and a aftermarket 9" for a rear end. Run a parallel 4 link with a pan hard as well.

I dont think I would have to go very big with my turbos. If the engine makes 1.3 HP per cube NA that is 528 HP. I think I could make the rest of that up with the induction system.

 

[Turboomni]

I dont think I would have to go very big with my turbos. If the engine makes 1.3 HP per cube NA that is 528 HP.

Wow thats alot of HP on a 400 ci with 8.5 CR NA

 

[MightyMats]

Just curious ,you want all this power on 93 octane ,I understand but to do what and behave how?

The goal is to have a bad *** C Body that I can take to the track and run into the high 8's if possible and drive home. Or go to a car show on sunday, pop the hood and eat some ice cream.

I'm not looking to daily drive the vehicle. But I want to have it run on pump gas for the ease of filling it up.

 

[MightyMats]

Wow thats alot of HP on a 400 ci with 8.5 CR NA

You are right. I would probably be lucky to get close to 470 hp.

 

[Turboomni]

You are right. I would probably be lucky to get close to 470 hp.

I am no expert by any means but if you could get that HP NA wouldn't the cam you used not be useful for a turbo charged engine? Two completely different animals aren't they?

 

[Xenon]

Already been done..
Ask furious70 what he did wit his....

@furious70

 

[MightyMats]

I am no expert by any means but if you could get that HP NA wouldn't the cam you used not be useful for a turbo charged engine? Two completely different animals aren't they?

Not exactly. A Turbo Cam is more like the cam you would see in a stock engine. You don't want much overlap if any at all. This is because you don't want to blow all your boost out of your cylinder.

Now lets look at a solid roller cam for a high compression NA engine. You want a lot of overlap (both valves open at the same time). That's that lopey sound you hear. This is because at 6k rpm your engine can't pull in air into the cylinder because your valve is only open for half the duration that your engine was spinning at 2k. The problem here is that the airflow of your engine is still the same. So your engine is now running out of breath. So a lot of overlap allows your engine to scavenge the air off the exhaust, giving it the extra air is needs up top.

Going back to what others have said most of the HP is going to come from the heads and how much CFM they can flow.

 

[MightyMats]

I think what this entire build is going to come down to is if the stock 400 Block can handle the power.

I was going over a stock 2.0liter GM turbo block with my uncle the other week. We were talking about how well the blocks are made today. (If you haven't seen one they are very cool tech wise) The main caps of the engine are essentially a girdle as well. It is a made from a solid piece of aluminum and extends something like 4" down from the bottom of the block. Virtually eliminating cap walk and stiffening the block significantly. A billet oil pan that is very beefy then bolts to the bottom of that main cap girdle. It's actually pretty incredible. This entire design allows you to push diesel levels of boost into the engine (if you have the fuel and cool inlet temperatures) and have the engine survive.

What I am trying to get at is that if the block can handle the power I feel like there is no reason I shouldn't be able to hit my target.

 

[70bigblockdodge]

My thoughts on not adding the cubic inches were to keep the rotating assembly lighter

It would be free cubic inches so why not?

I see what you are saying with airflow. The CNC'd edlebrock Victor Head has been tested to flow just over 350cfm at .500 of valve lift with is just about as good as I can get for my money

Trick flow 270s would be a better choice and easier on valve train cost.

I dont think I really need to be pushing over 15psi to achieve what I want. I am also not willing to hardblock the engine

Yes on 15 psi.
Living on borrowed time with the cylinder pressures you will be experiencing. The rpm level will distort the block.

One other thing to possibly consider. The 400 is "thin-wall" and usually .030" over is all you can bore them

This is not true is was made up to cover the fact that the foundry was having quality issues with core shift. The walls end up thin because of too much misalignment on the sand cores, wall ends up thin on one side of the parting line. A block that is to be used as a high HP block would be wise to have it Sonic checked. No need to spend good money on a weak link block.

 

[CBODY67]

Considering that the GM 2.0L Turbo motor has become their "workhorse" 4cyl turbo, in lots of applications, I highly suspect the oil pan is cast rather than billet.

"Girdles" have been around a long time, usually in the blown fuel engines. The Cadillac NorthStar V-8 uses a one-piece lower main cap piece, An alternative to cross-bolting the main caps? But also a source of oil leaks and seeps on those motors, by observation.

CBODY67

 

[twostick]

The goal is to have a bad *** C Body that I can take to the track and run into the high 8's if possible and drive home. Or go to a car show on sunday, pop the hood and eat some ice cream.

I'm not looking to daily drive the vehicle. But I want to have it run on pump gas for the ease of filling it up.

You need to talk to this guy in Finland. Jyriki.(sp?)



Kevin

 

[twostick]

You need to forget everything you know about going fast naturally aspirated to hit the number you are after. 500 cubes with good heads and a turbo will make more power than you can get to the ground by 6000 rpm or less. Parts live a long happy life when you keep the RPM out of the stratosphere.

Boost is just a reflection of restriction so don't get hung up on a number. 15 lbs through a set of stock 906's will get your attention but a set of Trickflow 270's might make the same amount of steam at 7 or 8lbs. More flow = less restriction = less boost to move the same volume of air into the engine.

E85 fuel will be your friend as well as EFI. A stock properly prepared block will live in the 1000 hp range provided you don't get greedy with the tune up. Detonation is what kills blocks, not horsepower.

Kevin