408 Stroker build begins.

[jasperjacko]

Hey Guys, Building a 408 magnum block. I would like to stay with shaft rockers. Any thoughts on a reliable way to oil the shaft rockers?

 

[Aspen500]

Hollow pushrods with oiling holes might work but, I am unsure if that would be sufficient to oil the rocker to shaft surface or not. It works for stud mounted rockers, shaft mounted maybe not?

The Magnum blocks have the oil passage bosses but they aren't drilled (from what I've read). Drilling them would work but some mods to the cam and bearings would be needed to allow oil to pass through.

 

[jasperjacko]

Hollow pushrods with oiling holes might work but, I am unsure if that would be sufficient to oil the rocker to shaft surface or not. It works for stud mounted rockers, shaft mounted maybe not?

The Magnum blocks have the oil passage bosses but they aren't drilled (from what I've read). Drilling them would work but some mods to the cam and bearings would be needed to allow oil to pass through.

It seems that Harland Sharp makes rockers that oil through the pushrods but that is another 900 bucks. I already have the la style through shaft oiling H S rocker setup. Hoping to use those.

 

[Aspen500]

Just dawned on me the pushrod cups int he rockers don't have oil holes, which would allow oil to get to the pivots. I was going to suggest PRW stainless alloy rocker set up. Less than HS but still $600+. I've got them on my BB and they work great (and also are a shame to hide them under a valve cover) but when I bought them, the whole rocker kit was only $290, 15 years ago. It says they're needle bearing in the description but they're actually bushed, which is better for street use.

3231811 - Small Block Mopar 273-360, 1.5 Ratio, Complete Kit

store.prw-usa.com

 

[jasperjacko]

The following is some specs and calculations I've come up with by using some of the online calculators. Many of you are more versed in this stuff than I am, so feel free to chime in with your thoughts. This is with the parts I have and am planning to get. Yes, I do know it will be a rowdy combo.
Trick flow 190 heads 60cc , Comp solid roller .597 int 260@050 .582ex 260@050 intake valve open at .050 22 btdc close 58 atdc, head gasket .027, piston to deck .017, 5cc valve reliefs.
The cam lift is gross, so I guess the lash would be subtracted? My best guess is the static comp is around 11.9, dynamic around 9.1, and cranking pressure around 200 +/- I'm thinking 3200-3500 stall, 3.91 gears, 3600lb car, low 11's, high 10's ? What do you think? Edit: intake duration is 260 not 266.

 

[Oldiron440]

More stall, 4500 - 5000

 

[M_Body_Coupe]

With that much duration @ 0.050" the 3200-3500 stall isn't going to cut it. You might want to re-think the 3.91 as well.

So here is a slightly different way of looking at it: what's your intended use?

 

[jasperjacko]

With that much duration @ 0.050" the 3200-3500 stall isn't going to cut it. You might want to re-think the 3.91 as well.

So here is a slightly different way of looking at it: what's your intended use?

FUN! Maybe give a Hellcat a run for its money drive to church and the dragstrip.

 

[M_Body_Coupe]

FUN! Maybe give a Hellcat a run for its money drive to church and the dragstrip.

So heed Oldiron440's advice, while the 4500-5000 converter stall speed may seem flat-out crazy...consider that you want your motor to be ON the second you punch that pedal!

The engine has to flash into it's sweet-spot if you intend on having the gitty-up-and-go power.

Consider the following, this is my hands-on experience:

1) 2800 stall converter, 3.91 gear and 238/244 @0.050" hydraulic flat tappet cam
- car was OK, moved reasonably well, but was soft at the bottom end

2) 4000 stall converter, 3.91 gear, same cam
- oh yeah, now we're talking, the higher RPM put the motor into that "instant power" spot

3) 4000 stall converter, 4.10 gear, same cam
- precisely where my ride needed to be right from the start, "instant power" due to the stall and immediate response regardless where in the RPM range the motor is, this is facilitated by the move from 3.91 to 4.10 gear, it made that much of a difference

You have a lot more duration @0.050" there, that 3.91 gear has to go and might even want to think about the high-end of the suggested stall speed.

What is Comp recommending for that grind?

 

[jasperjacko]

Talked to Harland Sharp today, I can take them my rockers and they can change the adjusters and drill the rockers for through the push rod oiling, or I can run a line in the lifter valley from the the lifter galley to the block deck to where the head oiling port is located.

 

[Oldiron440]

I'd choose the gear by quarter mile top speed if your going to run it.

 

[jasperjacko]

I'd choose the gear by quarter mile top speed if your going to run it.

Please shed more light, thanks.

 

[Ele115]

I'd choose the gear by quarter mile top speed if your going to run it.

That's a lot of it too. And now, at least here... these guys want to turn their 1/4 mile tracks into 1/8 mile... or 1/4 mile for a while, then 1/8 mile. We're switching gears a lot with this stuff. What's your 0-60? Your speed at the traps? E.T? What class? How many gears? But what you top out at is a BIG DEAL. Your home track is too

 

[Oldiron440]

There are plenty of speed/power calculators on the web but I use my old Moroso slide calculator.

The idea is to go through the light's at or just after peek power. Keep in mind converter slip is 15 percent + or - so vehicle speed will be that much slower than with a manual transmission at the same rpm.

You need to have a ballpark idea of the power you're going to make and at what rpm along with tire diameter and vehicle weight.

 

[MiradaMegacab]

Wallace Racing - Automotive Calculators

www.wallaceracing.com

 

[jasperjacko]

Engine combo should produce about 575-600hp at 6500 and 500 tq at 5000.

 

[jasperjacko]

New cam bearings came today...damaged from Summit. Looks like someone already tried to install them. You would think they could send good parts. Took two weeks to get.

 

[M_Body_Coupe]

Engine combo should produce about 575-600hp at 6500 and 500 tq at 5000.

You need some good head flow numbers to get there...what are you plans?

 

[jasperjacko]

Trick flow 190 they claim flow 293 cfm at .600 lift

 

[jasperjacko]

block and rotating assembly gets dropped at machine shop next week. (happy giggles)