400 Build Ideas

rumblefish360

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Thanks for that. Thanks can see the power from your description. On a 400, maybe not so much but certainly not impossible. It’s just build dependent. That’s why I said zigs worth a few HP. Can’t say how much until most of the cards are self out and even then, I’m only OK at best on what it’ll do on a dyno for proof of performance.

I’ve been told a .5 in et is a 100 hp. I think that is only good for us normal guys doing fun stuff. Yet again I lost my disclaimer, LOL, build dependent….
 

66Satellite47

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Rumble, I agree completely that things all depend on the build. But my point was that there is a bunch of power in pocket porting the stock OEM iron heads. Since that can be done by a very inexperienced person, I suggest that for people that are not pro builders. As I did more extensive porting, I learned that I was going too far. The 906 & 915 heads would crack after about 250 runs. I was taking too much iron out. But I was making pretty good power my 440's & 400/451's. Collecting parts was pretty easy in those days.
 

RockyPat

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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.
Sorry for the confusion. I would like a street-only motor with good street manners and solid power.

I am no expert, so I am still learning about building an engine. This post and forum have been very helpful.

I like the idea of 1HP per cubic inch. I think that is reasonable.

I have read the exact same things regarding aluminum heads vs iron heads. I will definitely price things out beforehand.

Thanks
 

RockyPat

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@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?
@RockyPat Have you decided on a cubic inch displacement to build?

I have some 17 inch Year One Magnums that I plan on using. I am not sure exactly what tire size I will be using.

It is a staggered setup with the rear wheels being 1" wider. Maybe I will go with slightly larger ones in the rear.

727 automatic transmission. I am not sure about the stall convertor.

The car should be close to its stock weight. I am not sure exactly how many lb's that is.

I appreciate you taking an interest in my situation rumblefish.
 

rumblefish360

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Well, the 17 inch wheels will offer a more modern tire. That’s a plus. Wider in the rear always looks bad ass. You have an automatic, good. A 4spd would be weird but not unseen. Hard to find, but it’s possible. That’s why I ask. It probably has what ever the factory put into it. If the transmission is a lock up, getting a converter for it is very pricey vs a normal non lock up converter. I don’t know what year they started that.

Do you know your gear ratio?
 

RockyPat

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Well, the 17 inch wheels will offer a more modern tire. That’s a plus. Wider in the rear always looks bad ass. You have an automatic, good. A 4spd would be weird but not unseen. Hard to find, but it’s possible. That’s why I ask. It probably has what ever the factory put into it. If the transmission is a lock up, getting a converter for it is very pricey vs a normal non lock up converter. I don’t know what year they started that.

Do you know your gear ratio?

Yes, I like having wider tires. I think they will look nice. I am fairly certain the car has its numbers matching transmission. I am not sure about a lock up vs a non lock up convertor. I need to look into that.

The car has a 3.23 suregrip with a 489 case. I am happy with the gear ratio. 3.23 seems to offer a good balance. The previous owner swapped out a peg leg pumpkin for the suregrip pumpkin.
 

66Satellite47

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For a street driver the 3.23 sure grip is good. If you are planning on a different convertor check around. The correct convertor will make the deal. Check with Dynamic(Frank Lupo), Turbo Action, A&A, or Coan. Top quality convertors are a key.
 
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rumblefish360

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Yes, I like having wider tires. I think they will look nice. I am fairly certain the car has its numbers matching transmission. I am not sure about a lock up vs a non lock up convertor. I need to look into that.

The car has a 3.23 suregrip with a 489 case. I am happy with the gear ratio. 3.23 seems to offer a good balance. The previous owner swapped out a peg leg pumpkin for the suregrip pumpkin.
Are you OK with the rpm the car runs at on the street & Hwy.?

Does anyone know if the 400/4bbl. engine still used the standard 4bbl. camshaft Chrysler used in the earlier years?
 

RockyPat

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For a street driver the 3.23 sure grip is good. If you are planning on a different convertor check around. The correct convertor will make the deal. Check with Dynamic(Frank Lupo), Turbo Action, A&A, or Coan. Top quality convertors are a key.

Thank you for the help! I will look into those convertor brands. I will try to figure out which convertor is the correct one for my situation.
 

RockyPat

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Are you OK with the rpm the car runs at on the street & Hwy.?

Does anyone know if the 400/4bbl. engine still used the standard 4bbl. camshaft Chrysler used in the earlier years?
I think I will be. I have only driven the car for probably 20 minutes. Right now it has a 1968 model year 383. I think it is the one with 9.2 compression.
 
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rumblefish360

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Thank you for the help! I will look into those convertor brands. I will try to figure out which convertor is the correct one for my situation.
Call up a converter place and tell them everything!!!
If you can even find out the weight of the car, that would be a big plus in dialing in the converter.
 

RockyPat

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Call up a converter place and tell them everything!!!
If you can even find out the weight of the car, that would be a big plus in dialing in the converter.
You are right. I will do that. I am sure they are helpful at those places.
 

rt-man

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A tremendous thread! I'm considering the same, replacing the 360 in my '73 SSP (similar weight to the OPs RR). I have my eye on an unmolested 400 near me out of a '78 Dodge van. All stock from air cleaner to oil pan. Budget build as I'm going to have to change most drivetrain components after the motor :( (727 vs 904, new driveshaft, 8.75 vs 8.25, gearing). Reuse as much as possible (cast crank, heads, pistons), raise the CR through machining. 1 hp per c.i. sounds good to me. Dual plane aftermarket, 650+ cfm carb. Heavy car, 15" wheel, looking for a cam that has good vacuum, not rumpity-rump. Think cruiser with balls.
 

rumblefish360

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You are right. I will do that. I am sure they are helpful at those places.
Good move and thinking. I don’t know who is close to you for this. I’m sure there is a great converter guy/company.
I went with a guy that used to be straight down my block. (Pretty much!) The company is Pro Torque. They do reallllly nice work. He custom stalled the wife’s OE “early” 904 converter since no one has the early odd spline count even in a replacement converter form. Then he did one for my manual shifting 904 for my Duster. Could not be happier.

When you get a guy that knows his stuff like no bodies biz, the results are ace. The more they know the better the converter they can build you. Tell’em everything! You’ll not regret it when the pro finishes with it.
 

rumblefish360

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A tremendous thread! I'm considering the same, replacing the 360 in my '73 SSP (similar weight to the OPs RR). I have my eye on an unmolested 400 near me out of a '78 Dodge van. All stock from air cleaner to oil pan. Budget build as I'm going to have to change most drivetrain components after the motor :( (727 vs 904, new driveshaft, 8.75 vs 8.25, gearing). Reuse as much as possible (cast crank, heads, pistons), raise the CR through machining. 1 hp per c.i. sounds good to me. Dual plane aftermarket, 650+ cfm carb. Heavy car, 15" wheel, looking for a cam that has good vacuum, not rumpity-rump. Think cruiser with balls.
That’s a lot of effort for a very little return and machining to raise compression on a 7.8-1 - 400 cid engine? Not trying to be a dick here but that sounds like a dream land build. For all the effort you wrote about, what are you expecting to do?

I’ve stuffed a ‘78-400 into a Duster. FWIW
“A cruiser with balls.” Is hard to envision.
The engine is in dire need of some compression.
 

rt-man

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Thanks, Fish. Looking for torque that I'm not getting with a SB. No racing, just street use. I've had 2 B-bodies with stock 440s, heavy cars (72 Satellite, 70 Charger), 906 heads, light porting, dual plane intakes, HP manifolds on both. 3.23 SG in both. Sorry, memory is fuzzy on cam specs. Mild cruisers until you punched it, then they jumped. No revving much past 4,000rpm. That's what I'm looking for out of this 400 build. And yup, I like the nostalgia look, so choked down with an Edelbrock dual plane and HP manifolds.

Go for it. Racers look elsewhere.

And what the OP neglected to say was, 3,400-3,600lb curb weight.
 

rumblefish360

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@rt-man If your going to tear the whole thing apart and just spiff up the machining, I suggest a set of KB pistons to raise the compression & then have everything else done to the 9’s. Nice valve job, square deck the block, you know… making the most of what ya got.
:steering:

IIRC, the 400’s also did use the HP or Roadrunner cam so getting what the 383 did years back but only better because your up 17 cubes and sweet machining should our do the old 335hp plus some nicely.
 

m79ded

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Subscibed... Basically considering the exact same thing. From what I have read 440 source uses a really short rod (6.535) with their 470 kit, which I am not a fan of. I would rather have a shorter piston with a 6.700+ rod to build a 470 to reduce side loading friction and reciprocating weight. The 500" option seems like a better assembly from 440 Source. Any experience there?
The 400 option is also there. Better economy 500hp within reason, cheaper, the satisfaction of giving old pars new life...
my third option is a LA based stroker in the 400" range but we need not discuss that here.
Did that combo and for a streetcar/mild race applications it's perhaps the best combo to go with, Extremely easy on cyl walls because of rod/ratio, easier on stock drivetrain, extremely quick reving and torque is outstanding. There's a reason Buick had a 3.90 stroke with 6.70 rods. Also read up some builds Andyf did with a 470. they are awesome. Keep with 6.70 rod and use light shelf 1.32 CH pistons you will be the happiest person
 

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