Mopar B-engine builds

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JGC403

JGC403

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Post up your 383 or 400 builds, please. I'm trying to get some ideas for the top end of my block. Goal is 500hp and 500 torque. Is this realistic for a 383, that needs to idle decent?

My build so far is: the block is a 1968 383 block, square decked, align honed, and bored .030" over. Stock crank, 440 H-beam rods, custom pistons, compression about 10.1:1 with 88cc heads. I am considering going with 440 source aluminum heads (84cc). Also not sure what camshaft I want to use. I have a Mopar solid purple cam P4120659, but thinking of going to a roller cam. And not sure what intake to use. This engine is going into a daily drive so needs an OK idle. This will be my first big block build so any suggestions are appreciated.
 
Can't beat the RPM Performer for the best at bottom end and top end combination. Demon 750 DP"r, since you're going to need adjustable rockers then Hughes with their shafts and hold downs. With a good set of heads and that cam 500 is doable but now matter what heads you get they're going to need work. Talk to Moper about the aluminum heads, member here. I've only used cast heads.
 
So the Mopar purple cam that I have will work? Do you know how the idle will be with it?

I have a set of 906 heads that I could use. But I would rather have the wight saving of the aluminum heads and the aluminum ones already flow more out of the box than the 906 do.
 
IMO, the Purple cam has a ruff idle. A smoother idle can be found in other cams. Also, IMO, a roller cam with a 112 C-line will idle really nice, offer more aggressive lifts and a higher ceiling of performance with reduced friction and not the need for cam lobe break in and special compounds to aid in break in.

Otherwise, a RPM, 750 or possible better cfm carb, and bowl ported aluminum heads are a excellent choice. I would also seek a larger tube header than the standard street size header. (1 step up in size)
Run as much compresion as possible.
 
I dont think a reasonable idle is doable at 500hp and I doubt 500tq is reachable that way either. Nevermind in the same package. You need to have the block deck height checked, unless it was set to blueprint height when you square decked it. Otherwise your pistons will be too short. I've never seen a 383 with a deck height anywhere near the factory spec. They are all tall by a lot. It's pretty easy to get 400 hp with a decent idle from a 383. But to get more, you have to cam and rev it like a 340... So the idle quality suffers. The other thing you could do would be to run a 3.915 stroked crank in it. That will go a long way to getting the 500tq and the decent idle and close to the 500hp.
 
I had the pistons made after the block was square decked. So the piston manufacturer made the pistons knowing the new deck height. I have the new deck height somewhere, but the deck height is shorter than production.

I'm not going to stroke it. It would help with torque output alot, but I already have to much money in my rotating assembly to change it out now.

Rumblefish360 what size headers do you mean?

Are there headers that will fit without me cutting up my engine compartment?

Thanks for the help so far.
 
Schmacher Tri-Y's chassis headers or TTI long tube headers, neither are cheap and Schmacher can be installed with the engine in the mounts and don't capture the starter especially if you install a mini starter.
 
You can also use the el cheapo hedman b body headers. They fit with a few dings.
 
Thanks
I like the TTI ones but the only ones that will fit the A-body are the 1.75" primaries, and they say it only will support 300-400hp.

The Tri-Ys will support 400-500hp.

I might have to go with the Schumacher or make my own.
 
"Reasonable idle" In my best Bill Clinton voice (and I do a good one) "It all depends on what the definition of reasonable is."
 
JGC403 said:
Thanks
I like the TTI ones but the only ones that will fit the A-body are the 1.75" primaries, and they say it only will support 300-400hp.

The Tri-Ys will support 400-500hp.

I might have to go with the Schumacher or make my own.
Click to expand...

Hold on Have a look at these. They are more of a race header.

http://www.maddogheaders.net/

And I think there is someone using 2" TTI with a low deck here....
 
StrokerScamp said:
"Reasonable idle" In my best Bill Clinton voice (and I do a good one) "It all depends on what the definition of reasonable is."
Click to expand...

True, if I remember correctly my jeep with the 403 pulls about 14" at idle, and has a idle that lets you know it isn't stock. So something around 14" would be nice at idle.



Those maddog headers don't seem to bad, 2" primaries to.

________

So far the Mopar cam I have power band is between- 2400-6600rpm
Eddy Performer RPM power band is- 1500-6500rpm

440source heads flow 290cfm@ about .6" lift.

The 440 source heads combustion chamber are 80cc. Going from the stock 88cc chamber to the 80cc chamber would up my compression from 10.1:1 to 11:1.


Found an article by Hot Rod Engines magazine. They did an intake manifold shoot out for the 383.

engine was bored 0.060".
12.5 compression ratio
Comp MM-series solid 263/[email protected], lift with 1.6 rocker arms 0.646/0.648
ported Edelbrock Performer RPM heads flowed 320cfm
850cfm carb

With the Edelbrock Performer RPM intake, peak power was 505hp@ 6500rpm and torque was 470lb-ft @5000.

Its not looking good for me to hit the 500hp mark and have a good idle.
 
That 659 solid cam is probably the best small solid cam ma mopar offers. But it's a lot smaller than that comp!
 
2" TTI's on a low deck with stock factory heads:
paulscar008.jpg
paulscar011.jpg
I didn't read the instructions that said they won't work until after they were in.
 
It's good you have the lower end done properly then. I still don't believe you will reach your goals with power brakes and a cam that will run them. If it was me, I'd run the RPMs or a set of Stealths but in both cases have them corrected and make sure the chambers are small enough to give you a static ratio of at least 10.5:1. For a cam, the Comp EX or Luntai Voo Doo "268" cams would do well and make some steam for you... Also, there are places that sell modifed B body HP manifolds for about $350 for the big block A.
 
moper said:
It's good you have the lower end done properly then. I still don't believe you will reach your goals with power brakes and a cam that will run them. If it was me, I'd run the RPMs or a set of Stealths but in both cases have them corrected and make sure the chambers are small enough to give you a static ratio of at least 10.5:1. For a cam, the Comp EX or Luntai Voo Doo "268" cams would do well and make some steam for you... Also, there are places that sell modifed B body HP manifolds for about $350 for the big block A.
Click to expand...

I think your right, I don't think I will hit the 500hp goal either. Should be in the 460-480hp range though.


BBBCuda, how difficult were those to install?
 
On that cam... I'm not sure it will operate your brakes. You can't have the lopey idle. For power brakes to be operational you need something in the 225° @ .050 at max... Also be very aware of the dynamic compression ratio. You will need to keep it around 8.75:1 to run pump fuel. You could go with a vacuum pump or can, or convert to the hydroboost setup. But really the best and cheapest would be to go with manual brakes. Then all you need is the master cylinder and broke push rod.
 
And manual brakes arent that bad. If you were to remove the booster from a KH setup Im sure the brakes would still work pretty damn good.All it may take is swapping in a master with a bigger piston.
 
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