Mopar B-engine builds

[JGC403]

You don't think that cam would pull at least 14" of vacuum?

 

[2734bbl]

The TTI's arent too bad to install.I found it's easier with the trans out though. You may have to test fit the mounts 2-3 to make them clear everything.

As far as the cam goes contact Porter racing heads. Dewayne can custom grind you one if you have detailed info for him and get you were you need to be.

Bullet cams is also another good place but you must have detailed info of your engine/trans and chassis combo for them to address your needs.

 

[moper]

Not in a 383 at idle, I don't think so, no.

 

[JGC403]

Really? The cam in my 403 has more advertised duration than that Lunati cam and I get at least 14" at idle. My 383 is bored 30 over so its about 389c.i. now. The 403 isn't that much bigger only 14c.i.

 

[SGBARRACUDA]

Really? The cam in my 403 has more advertised duration than that Lunati cam and I get at least 14" at idle.

Advertised duration is not a good method to compare cams. duration @.050 is best along with overlap consideration.

 

[BBBCUDA]

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?

Well, I do have a couple things in my favor: motor plate, no torsion bars. The passenger side took 3 minutes from underneath, the drivers side took 12 minutes. I did keep the factory head studs, which has some advantages/disadvantages.

 

[moper]

The 403 has a 4" stroke. The 383 only has 3.38. Think of what the 318 felt like vs now, and you'll see what the difference the stroke makes. That was why I suggested that first thing. The 383/400s have always been hobbled by that short stroke so you end up having to rev them (and cam them) to make power, and that means poorer idle/vacuum. Just my opinion tho. If you feel it will do it, go for it.

 

[JGC403]

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.

Just checked the dynamic compression ratio with that Voodoo cam, 60330. With a static compression of 11:1, It would be 9.82:1. I know you can get away with a little more compression with aluminum heads compared to cast iron.

The 403 has a 4" stroke. The 383 only has 3.38. Think of what the 318 felt like vs now, and you'll see what the difference the stroke makes. That was why I suggested that first thing. The 383/400s have always been hobbled by that short stroke so you end up having to rev them (and cam them) to make power, and that means poorer idle/vacuum. Just my opinion tho. If you feel it will do it, go for it.

The 403 pulls a lot harder than the 318 did. Specially since the stock computer's redline is 5000rpm.

The 383 will like to rev higher.


I emailed Lunati, just to see what they say.

 

[moper]

You can't run dynamic that high on pump fuel. With a tight quench and aluminum heads, 8.75:1 is about max for the 10% ethanol pump high test I can get. This is why I say you cannot do all of what you want. Lose the brakes... It will be a lot easier. Then you can just run a larger duration cam, ge the dynamic down to reasonable, and not sweat the vacuum at idle.

And on the 318... You missed my point. The reason it idles well with such a large cam is that the stroke is 20% longer than the 318s. You went from 3.31 to 4.00... In order to have a comparable idle with a similar cam in the 383, you'll have to increase the stroke to 4.10" from 3.380".

 

[Plik]

JGC403, What is the CC numbers for your pistons? Do you have any pics showing the dome?

 

[rumblefish360]

And on the 318... You missed my point. The reason it idles well with such a large cam is that the stroke is 20% longer than the 318s. You went from 3.31 to 4.00... In order to have a comparable idle with a similar cam in the 383, you'll have to increase the stroke to 4.10" from 3.380".

Funny how MP has a 4.15 crank now isn't it?

 

[JGC403]

JGC403, What is the CC numbers for your pistons? Do you have any pics showing the dome?

12.5 cc dome.

 

[JGC403]

So decided to go with manual brakes.

Still looking around for a cam, looked at Crower's website but they don't have any information.

Intake will be Edelbrock Performer RPM, power range 1500-6500rpm
Heads will be 440 source stealth heads.

I can adjust the static compression ratio with different head gaskets between about 10.9 - 11.1. I can lower it more if I go with copper head gaskets. But I don't know to much about them.

Criteria for Cam:
Has to idle around 700rpm
Has to be a roller, hydraulic or mechanical is fine
Lift less than 0.600"
Max RPM about 7000

There are just so many cam manufacturers out there I don't know where to start.

 

[needsaresto]

Yup there are quite a few.As far as a retrofit roller cam i think comp has some of the better choices. Lunati Voodoo as well. They seem to be the main choices around here.

 

[JGC403]

Yup there are quite a few.As far as a retrofit roller cam i think comp has some of the better choices. Lunati Voodoo as well. They seem to be the main choices around here.

With a static compression of 10.9:1

The Voodoo cam I was looking at, I will have to high a dynamic compression ratio.
http://www.lunatipower.com/Product.aspx?id=1582&gid=290

And it says it will already have a lopey idle. The next Voodoo Cam up says that its a rough idle and better in the 400-440 engines. So is this cam going to be way to much for a 383? And this cam will still have a high dynamic compression of 9.6:1.
http://www.lunatipower.com/Product.aspx?id=1583&gid=290

The Biggest they recommend for the 383 is this one, and the dynamic compression still will be to high at 9.26:1.
http://www.lunatipower.com/Product.aspx?id=1585&gid=290

 

[needsaresto]

Well I kinda like the middle cam. It seems the others are either not enough or too much.

The big one would be perfect in my 451, but it has 70 cubes on your motor and will not be as radical.CID seems to swallow up duration and lift,mellow it out some.

 

[moper]

What exactly are the pistons? Flat tops, dishes, domes? What is the volume of the piston top? Are you certain your numbers are right? I have a hard time with a stock stroke getting those compression numbers unless they have monster domes or the heads get whacked a lot...

 

[JGC403]

Ross Custom pistons. When I got them made I was going to use the 906 heads. So they are built for 10.1:1 compression ratio with the 88cc heads.

Bore: 4.28"
Stroke: 3.38"
Rod length: 6.765"
Compression height: 1.493"
Dome 12.5cc

Engine Deck height: 9.960" They took off as little as possible, just enough to square it up.

Also went with the 1/16", 1/16", 3/16" rings.
The pistons are coated with a dry film lubricant on skirts and a ceramic coating on the piston top.

 

[moper]

Check your calculations. Specifically the piston head volume. Some calculators need that as a negative number for a domed piston. When I run your numbers with an 84 cc head I come out with 10.5:1 static and somewhere around 8.9:1 dynamic with that 60330 cam. I'm guessing on the intake closing point tho. It's a little high for and engine with little to no quench. I like to stay under 8.5:1 in that situation but some guys like to run more. But any cam with an intake closing point later than 45° ABDC would be fine with an 84cc head.

 

[SGBARRACUDA]

By your numbers your piston should wind up being .032 down from the deck at TDC. I will divide the stroke in half, add the comp. height and rod length to inform my machinist what deck height I want so the piston is where I want it in relation to the top of the deck.

 

[JGC403]

By your numbers your piston should wind up being .032 down from the deck at TDC. I will divide the stroke in half, add the comp. height and rod length to inform my machinist what deck height I want so the piston is where I want it in relation to the top of the deck.

I got 0.012" when I did it by had and with an online deck clearance calculator.

 

[JGC403]

Check your calculations. Specifically the piston head volume. Some calculators need that as a negative number for a domed piston. When I run your numbers with an 84 cc head I come out with 10.5:1 static and somewhere around 8.9:1 dynamic with that 60330 cam. I'm guessing on the intake closing point tho. It's a little high for and engine with little to no quench. I like to stay under 8.5:1 in that situation but some guys like to run more. But any cam with an intake closing point later than 45° ABDC would be fine with an 84cc head.

I got the same compression ratio as you with a 84cc head. But The 440 source stealth heads have a 80cc combustion chamber. That would bump up the compression ratio to 11:1.

The Eddy Performer RPM heads have a 84cc chamber. So I would have to use those.

That 60330 intake closing point is 41.5* ABDC
The 60331 intake closing point is 44.5*

What dynamic compression ratio calc. are you using? I am using this one: http://www.wallaceracing.com/dynamic-cr.php

With the 44.5* closing point I am getting a dynamic compression of 9.23:1 with a static compression of 10.5:1.

 

[SGBARRACUDA]

I got 0.012" when I did it by had and with an online deck clearance calculator.

Your right I was a little off on my gazintas.

 

[moper]

I'm pretty sure Stealths are usually larger than 80cc when you measure them. They are modeled after the RPMs and they are typically 84-85ccs. I recall earlier builds where they were 84ccs. But honestly, I've only personally held one set of them and never used them on my own builds. Given the choice I buy Edelbrock first.