400 Build Ideas

[RockyPat]

Kit is internally balanced, so it would require a neutral balance balancer and torque converter/flywheel.
Usually the original 50 year old balancer needs replaced anyway.

Rebuilding with stock parts is a bit easier because they all worked together before.
The stroker kits, everything is new, so everything needs to be inspected and checked, and all clearances verified.

I have gotten a kit where the rod bearing notch in the rod was machined in the wrong place and it moved the bearing too close the the crank fillet. Showed up as tight rod side clearance. Engine was pretty much together at that point, so I just chamfered that rod bearing a small amount. Has not been a problem, but now I know to check the bearing fit when I get the rods in case I need to return them.

Thank you for the help. I will make sure to inspect things regardless of the route I choose to go. Important stuff.

 

[RockyPat]

I don’t know about that. Prehaps the “230” casting number has the edge but as far as something head and shoulders above another block, I am unaware.

Well, efficient now through cubes can be a MPG draw back later due to the extra cubes. A lot of this is dependent on what your power needs are and any mileage concerns if any exist.

Exactly. Read on below.

Thank you!

Yes, a stroker is a barrel and a half of monkeys, is it needed. I’ve noticed that a well done set of heads can carry a camshafts supposed listed rpm band even further out and continue to make very good HP.

I think the first time this became evident to me is when I payed attention to Dodges return in NASCAR truck series when I heard they were regulated to a 9.0-1 compression ratio. I said to myself how the heck are you supposed to make HP with just a 9.0-1 ratio?

Ahhhhh the things we learn paying attention to the smart people running and gunning there rides with there talent, brains & mechanical abilities being pushed.

How does a limited small cubic inch small block & compression ratio limited small block engine at that make over 700hp? LMAO! Well, now it’s history you can look up and ask them about.


Like I said rocky pat, build what ya want.
For a fun street car, IMO, huge cubes need not apply when you’ll just be blowing the bologna skins off the rims.

I don’t how easy it is to invest in a OD trans or the big blocks, but I’d look there as well.

Also, I hope you get to dyno the engine. Pay attention to the exhaust. There is a lot of power there left behind when people don’t pay attention and they just throw on exhaust pipes when they get home.

Thanks for all the information!

Definitely a great point about the MPGs. I would like something that is not a total gas hog. That would be nice!

I will have to look into the truck action!

I would love to add an OD transmission to my ride, but they are expensive!

 

[RockyPat]

Rocky, keep in mind all strokers do add torque. The rest of the car needs to be able to handle the added torque. The stroker kits available with all the new parts are very attractive. Rumble makes a very good point, do a good exhaust system.

Very good point. I will definitely need to upgrade the suspension!

 

[RockyPat]

Thanks. We have all heard the old racers trick with the header collector and a crayon or paint…. Of course!
Well, on the dyno, you can make a few low rpm pulls and find your best length. The length of pipe should be the same diameter of the header collector.

Alwo while that stroker adds torque by the pay loader bucket load, if you can’t get it to the ground in a effective manor, what’s the point? Get that suspension working for you. No matter what engine size and power output.

Thanks for the advice! A dyno session would be sweet!

I am going to try my best to avoid having traction issues with excess power. I want everything to work well in unison.

 

[RockyPat]

I would do a 400 with the cast crank and focus most (money wise) on the stock heads (346/902/452 etc. castings). If the bores/pistons are good enough for a re-ring, mill the heads .060" on the deck and .072" on the intake face, so the manifold will line up. If you need a bore-job, go straight to flat-top KB pistons or the ICON forged units, for valve reliefs and compression WITHOUT the excessive head milling. Do all the factory tricks like a windage tray and baffled oil pan, add a HV oil pump and fully grooved main bearings. A killer camshaft if you want a great sound at idle and great driveability, is the Comp Cams 275DEH, #21-406-5. It works with #911 drop in Comp springs or equivalent and stock rocker gear. If you can find/afford a Edelbrock RPM or DP4B/ Performer 383 or Weiand 8008 intake get it, or use the stock intake which isn't as bad as people think. A 750 carb and HP exhaust manifolds or headers and 2.5" exhaust with straight through (Salute, FlowFX, Dynomax UltraFlo, Pypes RacePro, etc.) mufflers and you're set. This setup responds to a 727/318 torque converter, with the wide ring gear (11" unit) and 3.23-3.55 gears. I had this setup (with the milled heads and original OEM pistons) in a '70 Challenger R/T with 3.23 gears and it was a handful, while beeing really docile and MPG friendly (for a BB MoPar)!! Your friend may think you have a 451!!

Thank you for the very detailed advice! I appreciate it. The build sounds like a great idea. I will definitely keep this in mind when I find a 400 for my car! I like it being a mix of power and mpg. I have the 3.23 gears already!

 

[66Satellite47]

Rocky, you can great street performance with a 400, cast crank, and good heads. One semi inexpensive option is some 516 closed chamber heads that are pocket ported(do it your self) with adding the larger exhaust valves. That would make great street power without needing to change pistons. If it needs boring and new pistons the newer pistons with the late model heads are good. The newer OEM heads still would still like pocket porting. You would be very surprised what the improvement is from pocket porting a BB OEM head is.
If go stroker you will be amazed by how much your tires will be hurt, and how much you will have to steer it off a standing start with any street tire.

 

[greerf]

Take a sec to Thank RockyPat for posting this as well as everyone's input! I'm in the same boat and sincerely appreciate all of the technical expertise/insight. I was dead set on a 440 but the more I read threads like this and others the more i'm inclined to build a Stroker! Thanks All

 

[RockyPat]

Rocky, you can great street performance with a 400, cast crank, and good heads. One semi inexpensive option is some 516 closed chamber heads that are pocket ported(do it your self) with adding the larger exhaust valves. That would make great street power without needing to change pistons. If it needs boring and new pistons the newer pistons with the late model heads are good. The newer OEM heads still would still like pocket porting. You would be very surprised what the improvement is from pocket porting a BB OEM head is.
If go stroker you will be amazed by how much your tires will be hurt, and how much you will have to steer it off a standing start with any street tire.

Thanks for the information! It would be fun to build a stout 400 with stock internals to keep from having to beef the rest of the car up too much. A stroker kit sounds like an intriguing option as well... My main issues with one would be the need to build the rest of the car to withstand the power, the cost (albeit for what you get not bad at all), and the decreased fuel economy. I will definitely keep in mind porting OEM heads if I end up going that route.

 

[RockyPat]

Take a sec to Thank RockyPat for posting this as well as everyone's input! I'm in the same boat and sincerely appreciate all of the technical expertise/insight. I was dead set on a 440 but the more I read threads like this and others the more i'm inclined to build a Stroker! Thanks All

Thank you! I am glad that you and others are gaining insight from this thread. Thanks to all the knowledgeable people who provided their insight. It has definitely helped me.

 

[66Satellite47]

Thanks for the information! It would be fun to build a stout 400 with stock internals to keep from having to beef the rest of the car up too much. A stroker kit sounds like an intriguing option as well... My main issues with one would be the need to build the rest of the car to withstand the power, the cost (albeit for what you get not bad at all), and the decreased fuel economy. I will definitely keep in mind porting OEM heads if I end up going that route.

You will be amazed at the power gained from pocket porting any of the OEM BB heads. New aftermarket alum heads make it a little easier at the pump. The stroker option will produce A lot more power, but if you don't really need it, why? A stock cast crank 400 with good heads and a moderate cam will be a great street ride. If you want to go drag racing, then it all depends on your wallet.

 

[Babyblue66]

I would highly recommend a Hughes cam. I had some Mopar cams in the past and the Hughes cam I have now is just awesome. They are a sponsor here too.

I have used 2 Hughes cams in 440s. Both perform very well for the size they are. I made 415hp in a 7.5 to 1 440 with one of them.

 

[Babyblue66]

Also, I recently built two 383s that made 380 hp and had stock intakes with mild cams. At the same compression a 400 would just make more. If you look you can find my posts. I describe everything I did to make about 1 hp per cubic inch very easily.

 

[RockyPat]

You will be amazed at the power gained from pocket porting any of the OEM BB heads. New aftermarket alum heads make it a little easier at the pump. The stroker option will produce A lot more power, but if you don't really need it, why? A stock cast crank 400 with good heads and a moderate cam will be a great street ride. If you want to go drag racing, then it all depends on your wallet.

You are exactly right. I only plan on street driving, so a street/strip build is not what I am looking for. Aluminum heads are intriguing.

 

[RockyPat]

I have used 2 Hughes cams in 440s. Both perform very well for the size they are. I made 415hp in a 7.5 to 1 440 with one of them.

That is great power. Good to know! Thank you for the info!

 

[RockyPat]

Also, I recently built two 383s that made 380 hp and had stock intakes with mild cams. At the same compression a 400 would just make more. If you look you can find my posts. I describe everything I did to make about 1 hp per cubic inch very easily.

Thank you! I will look at your profile to find your posts. I am interested in reading about what you did. A 400hp 400 would be nice.

 

[rumblefish360]

You are exactly right. I only plan on street driving, so a street/strip build is not what I am looking for. Aluminum heads are intriguing.

You said your not looking for a street strip model but most every post points that way. Though it may never hit the track.

Personally, I like a hot rod. When a guy says to me he built a street strip car, I’m thinking there’s a cage in there right away.

For power out of the 400, stock heads are fine. I’d call’em good to a reasonable easy driving 400 hp.

Bowl porting is a few more HP. The amount is really build and parts selection dependent. The use of aluminum heads can simply be used as stock replacement or a really nice street machine that will make more power than an iron head. The cost of an iron head rebuild plus a bowl porting may exceed the cost of a new aluminum head and not perform as well.

Do check pricing before jumping.

 

[rumblefish360]

@RockyPat You said you have 3.23 gears. What tire size are you going to use?
Automatic trans?
What is the cars weight?
Are you willing to purchase a new stall converter or would you rather keep it stock?

 

[66Satellite47]

Pocket porting on an OEM iron head is not a few HP. It is probably nearly 50 HP with any 516, 915, 906 or other head.

 

[rumblefish360]

Pocket porting on an OEM iron head is not a few HP. It is probably nearly 50 HP with any 516, 915, 906 or other head.

I’ll agree with a “*”. Why?
It’s build dependent.
It’s impossible to issue correctly or honestly say in a blanket statement that pocket ported heads are worth 50 HP. It’s simply impossible.

Also, while 50 hp is often seen as a substantial gain, it also depends on how much power you see as such and where a making the power under what build terms and the cars purpose.

As an exaggerated example, 350 to 400 HP is awesome while 1500 to 1550 is or much, though I thoroughly! Realize that at that extreme level that work is already done.

So, will pocket porting any BB head on a ‘78 - 400 smogger equal 50hp?

If so, what about on a rebuilt high compression 400 with a roller cam?

Even more so, how about a 440? A 543?

When it comes to big blocks, bigger gains are easier to achieve than a small block. Cube for cube, pound for pound, build dependent, there is some HP with a bowl porting vs a full porting vs an aftermarket head on any size engine with various results in similar gains percentage wise for the cubic inch the engine is.

 

[66Satellite47]

Rumble, maybe my 50 HP estimate may be a bit high. But my 1st couple pocket portings on 906 heads picked up about .5 in ET with both my 426W and 440 with 11.5 CR and a 585 solid cam, 3650# car. My later motors 400/451 & 440 with bigger cams including solid rollers got a lot more porting. They were around 600 HP. Not sure what they current roller cams would do. The increase in iron head flow from basic porting will really help even a low CR 400. Bigger motors sure do make more power & torque.