408 Stroker build who's keen to watch this one :)

[jasperjacko]

did you get your afr's figured out yet?

 

[Bruceynz]

Nope, got no jets and my carb guy proving hard to get a hold of

 

[jasperjacko]

I think your engine just needs someone good at tuning.

 

[jasperjacko]

My car went from a 14.1 to a 13.65 with just tuning. Same gear, tires, ignition. and carb.

 

[Bruceynz]

well the only way to get this car sorted and gets some numbers is down to the dyno, its going to cost a minimum of $800 so dam expensive!

as not many Dynos in my city they can charge what they like!

 

[Oldiron440]

I'd say if your going to build the 408 don't bother with the 360 just build the 408 and dyno that if you need help sorting it out.
Even if you get the 360 making 350 hp your going to build the 408 so why spend the money.

 

[jasperjacko]

I've never been to a dyno. That's a lot of money.

 

[Oldiron440]

I pay 400 for my engine dyno work but I get the good buddy discount.
My guys put in a chassis dyno but not to that point yet.
I don't think at this point I would build a motor without it going on the dyno. You break in the cam and the rings are seated plus your able to check things over before you put it in your vehicle.

 

[Oldiron440]

Do you have a 670 street avenger carb on your 360?
I've been reading a thread on moparts on the 670 and how far off it is out of the box and how hard it is to tune. Also that the 770 works much better, the 570 works and the 770 does also, but the 670 is a pain in the butt. If you have a 770 try it.

 

[Bruceynz]

My 360 carb is a 600 holley. The bulk standard carb.

 

[Oldiron440]

It's a good carb and isn't hard to tune.

 

[Bruceynz]

This is my problem - I built this 360, it goes ok but not as good as i had hoped, my 360 is an EQ headed Magnum engine with the 209/217 .5" lift cam, so then I thought well lets get big block power into it in a small block package, so I have been getting everything together, then I found the 40 over KB416 will not fit into a Magnum block, also when I got the block from the USA its perfect in the bores, so I need to get some KB416 STD from USA, by the time I get them to NZ they will owe me $1000NZD and no matter what you say a $1000NZD is still like $1000USD for you guys. Then my mopar friend in NZ said well to be honest you never really gave that 360 a very fair go did you, just bolted carb on set timing at what you thought, drove it and then say your not 100% happy, I them started researching and was looking at the Indy create motors and see with a similar set up (eq and indy heads similar) and with same cam, .5 points in comp they were knocking out 380HP so I was going to try and get the 360 running good, save up the money to get some more pistons. One thing that intrigues me is the blueprint motors compared to indy motors check this out. To me the blue print has higher spec cam, higher spec heads yet is down on power.


Below is the blueprint 408 spec engine

• Aluminum Cylinder Heads - 63cc chamber 2.02" intake/1.60" exhaust valves 171cc intake/77cc exhaust runners

• Flat tappet .545 Intake / .545 Exhaust 241 Intake / 247 Exhaust duration @ .050 - 110 degree lobe separation

• 34 degrees total at 4000 RPM

• Aluminium intake manifold Distributor 750cfm carb Valve covers, oil pan and timing cover Brass freeze plugs Dyno tested and shipped with results

445 HP / 500 FT LBS



Below is the Indy spec motor

408 Magnum with Indy MA-X cast Iron Iron Heads
460 Horsepower @5600 RPM
480 Torque @4100 RPM
Engine ran with Brad Penn 30WT break in oil
Fully prepped 360 Magnum block
4.020 bore--4.00 stroke As pictured
Eagle SIR rods $7,125.00
New Indy MA-X cast iron heads
1.920 x 1.625--5/16 stem valves
Hydraulic roller cam
.467 / .482--208 / 216--HR113

M.P black Magnum valve covers

Included for $160 with complete engine:

M.P. Single plane intake Orange control box
750 CFM Edelbrock carb

 

[Oldiron440]

Then learn how to tune a Holley, for the most part it's power valve, jets and squirters. Your vac secondary spring is easy, put the middle one in and you will have to go up or down or stay the same. It's not magic.
Big thing is get the timing correct first, get what you need for initial then the rest by 2500rpm.

 

[Bruceynz]

I played with timing, it's at 38 and idles at about 20, starts ok, no pinging sounds, I have quick change vac thing and got the springs sorted. Found the spring where it bogged and then put the next stronger one in. What I think happens is it the afr is in the 12s then about 3000 it gets to 10.86 then it seems as the vac secondary opened the afr came back to 13ish, then I ran out of road lol lol and went home, problem is my test road is 30mph and at 4000rpm ish the thing getting along pretty good

 

[Oldiron440]

When the power valve opens there will be a moment of rich on your gauge.

 

[Bruceynz]

Lasts for a while

 

[Oldiron440]

I've never seen a vac secondary go rich when the secondarys open it usually goes lean.

 

[Oldiron440]

How much vacuum do you have with the car idling in drive and witch power valve do you have in the carb now?

 

[Bruceynz]

I dont know I need to get it lookef at by someone who knows what's going on, who knows how accurate my afr guage is, wideband O2 sensir at collector in left heafer.

 

[Bruceynz]

66 and 6.5