Desktop Dyno for my 401 Combo?

[flyusmc]

Hey all,

My 401 block is in the machine shop right now, but I’ve had a couple changes to my 401 build and was hoping someone may be able to give me a rough desktop dyno estimate.

> Block .30 over
> Pistons Standard (8.5’ish)CR but….
> Deck will be milled to support 9.0:1 CR
> Heads stock, but will be ported.
>
> Intake will be a Edelbrock Performer
> Carb will be an Edelbrock 1406 600cfm
>
> Cam will be a Summit K8600 Spec’s below
>
> Brand:
> Summit
> Product Line:
> Summit Cam and Lifter Kits
> Part Type:
> Camshaft and Lifter Kits
> Cam Style:
> Hydraulic flat tappet
> Basic Operating RPM Range:
> 1,500-4,500
> Intake Duration at 050 inch Lift:
> 214
> Exhaust Duration at 050 inch Lift:
> 224
> Duration at 050 inch Lift:
> 214 int./224 exh.
> Advertised Intake Duration:
> 272
> Advertised Exhaust Duration:
> 282
> Advertised Duration:
> 272 int./282 exh.
> Intake Valve Lift with Factory Rocker Arm
> Ratio:
> 0.472 in.
> Exhaust Valve Lift with Factory Rocker Arm
> Ratio:
> 0.496 in.
> Valve Lift with Factory Rocker Arm Ratio:
> 0.472 int./0.496 exh. lift
> Lobe Separation (degrees):
> 112
>
> Summit double roller timing chain
>
> I think right now I will try and use headders.-
> Not sure which brand I have, but they do have
> emission’s tubes on them/heat riser.
>
> Ignition will be a Bulltear HEI system.
>
> Any Desktop Dyno est would be awesome.
>
> Thanks Guys
> FLYUSMC

[shackwrrr]

I can but not right now I am in class. when i get time I can

[flyusmc]

Originally Posted by shackwrrr

I can but not right now I am in class. when i get time I can

Cool, Thanks.

I'm more concerned of how the torque curve will look.

FLYUSMC

[Elliott]

Gonna want to list your exhaust, stock or header...

[flyusmc]

Originally Posted by Elliott

Gonna want to list your exhaust, stock or header...

> I think right now I will try and use headders.-
> Not sure which brand I have, but they do have
> emission’s tubes on them/heat riser.

[flyusmc]

Originally Posted by shackwrrr

I can but not right now I am in class. when i get time I can

Any Luck? I've had people tell me anywhere from 275-380 HP. Again I'm more concerned about the TQ curve, but as we all know HP bragging rights are nice to have.

[Elliott]

Doh... be glad I'm not plotting the numbers for you.

[shimniok]

Used specs, assuming 112* ICL and 9:1, small tube headers/mufflers, 650cfm carb, stock AMC heads (Mike Baxter model), dual plane manifold.

Without getting too attached to the numbers, it looks like an awesome, flat torque curve from 2000 up... (slightly peaked at 3500) hp peak at 5000, maybe a bit high for my taste but who cares with that much torque.

Table:

[j20brett]

flyusmc:

If you dont mind me asking, how much did all these parts/ machine shop/ rebuild run you? trying to get an estimate for the future.

[flyusmc]

Originally Posted by j20brett

flyusmc:

If you dont mind me asking, how much did all these parts/ machine shop/ rebuild run you? trying to get an estimate for the future.

I'm going to venture to say around 2500-3000 , not including my own labor pulling the engines or cost for me to buy the 78 Cherokee I pulled the engine from.

I'll have a better cost estimate when I get the engine back from the machine shop.

FLYUSMC

[flyusmc]

Originally Posted by shimniok

Used specs, assuming 112* ICL and 9:1, small tube headers/mufflers, 650cfm carb, stock AMC heads (Mike Baxter model), dual plane manifold.

Without getting too attached to the numbers, it looks like an awesome, flat torque curve from 2000 up... (slightly peaked at 3500) hp peak at 5000, maybe a bit high for my taste but who cares with that much torque.

Table:

Thank You!
That looks pretty good. The only things I have questions on are:
1. The stock heads will be ported.
2. I will only be using a 600 CFM Edelbrock 1406.

So who knows maybe maybe the two will balance out?

The reason I'm going so Torque heavy is that in the Marines I move every 3 years and have to pull my 1968 Plymouth Barracuda on a 16' Trailer. Going over the rockies requires all the Torque and pulling power you can get!

[shimniok]

Playing with DD a little, 50cfm hardly matters... if you find the limits of the 600cfm, switch to a Qjet -- you'll get as much CFM as the motor needs.

If you can get me the flows at various lifts as below, fl I can model it in DD... really for porting they always say you should see before/after flows to "prove" the porting helped beyond just making the head a little lighter.

[jeepsr4ever]

If you want real head numbers they are listed on the Bulltear forum. They will be handy for desktop dynoing

[shimniok]

Originally Posted by jeepsr4ever

If you want real head numbers they are listed on the Bulltear forum. They will be handy for desktop dynoing

Didn't know --cool.

The numbers above are based on real world bench flow testing by Michael Baxter (long time FSJ guru) on a standard AMC big valve head.

Figuring that porting has varying results, it'd be interesting to model his results specifically but could get an idea maybe from Bulltear...

Michael

[jeepsr4ever]

His numbers are off. We have flowed multiple sets of the same casting number. The first flow numbers we have are about the average. I have never heard of Michael Baxter but I wonder if he used 28lbs when he was flowing.

[jeepsr4ever]

Here you go

Raw, unported stock heads.
3231475 (and -2) from 1978-1985 used in all AMC V8 360
64ccs
Lift.....Exhaust...Intake
.200 107 142
.300 137 186
.350 143 200
.400 143 204
.450 144 208
.500 N/A 209
.550 N/A 211
.600 N/A 214
3220502 (and -2) from 1974-1977 Used in AMC 360 and 401
59.2ccs
Lift..... Exhaust...Intake
.200 114 144
.300 132 188
.350 137 201
.400 140 204
.450 142 210
.500 144 212
.550 N/A 213
.600 N/A 216
3196291-C Used only in 1970 390 and 71' 401
61cc
Lift.....Exhaust...Intake
.200 101 138
.300 137 185
.350 147 202
.400 152 212
.450 153 212
.500 154 214
.550 155 217
.600 N/A 219
N/A means their was simply too much turbulence to measure accurately.

Edelbrock heads no valve size change ported
Intake 2.02, Exhaust 1.60....11/32 stem, back cut valves
54ccs
Average flow intake 236.6, Max 275CFM
Average flow exhaust 179.1 Max 214CFM
Lift.....Exhaust...Intake
.200 106 134
.300 145 182
.350 163 218
.400 176 244
.450 190 259
.500 200 270
.550 206 274
.600 212 274
.650 214 275
Now with 2.080 Intake valves and a little more exhaust work
Average flow intake 253.5 Max 296CFM
Average flow exhaust 182.1 Max 216CFM
Lift.....Exhaust...Intake
.200 113 143
.300 149 202
.350 167 231
.400 181 254
.450 191 273
.500 201 278
.550 207 280
.600 214 286
.650 216 292
.700 .... 296

[shimniok]

Originally Posted by jeepsr4ever

Here you go

Thanks, will plug that in when I get a chance!

Michael

[dusty]

Originally Posted by jeepsr4ever

..................................600 N/A 216
3196291-C Used only in 1970 390 and 71' 401
61cc
Lift.....Exhaust...Intake
.200 101 138
.300 137 185
.350 147 202
.400 152 212
.450 153 212
.500 154 214
.550 155 217
.600 N/A 219
N/A means their was simply too much turbulence to measure accurately.

Edelbrock heads................................

I believe MC ment to put 51cc's on the 291 heads not 61cc

[jeepsr4ever]

ahhh....ooooo

[Elliott]

Don't recall were I got these flow specs by casting #:

AMC Head Flow for #291 (’70 51cc), 090 (’73 58cc), 502 (’74 60cc) Heads:

AMC 2.02 valve heads:

Intake:

291 090 502
.100 71 74 70
.200 127 156 143
.300 179 201 192
.400 209 219 213
.500 217 226 220
.600 222 232 228
.700 228 238 236

Exhaust:

291 090 502
.100 55 56 59
.200 107 112 113
.300 135 141 146
.400 142 145 150
.500 145 149 152
.600 145 150 153
.700 145 151 153

The 291's are 3196291, 1970 51 cc chamber heads, the 090's are 1973 58 cc heads, and the 502's are 3220502 1974 60 cc heads, I have tested an example of all 3 combustion chamber sizes. The 291 and 090 heads have a multi angle valve seat, the 502's are utterly stock. There is no porting on any of these. They were all tested as identical as I could make it - same port, valves, inlet radius plate, flow bench, day, operator, and bench temperature. The correction factor for the bench temperature is a reduction of 1.6%, I couldn't be bothered adding it in.


All the flow numbers are at 28" to be the same as most of what you see in the magazines. The bench was a SF110, which can't test at 28", so most of the testing was at 7", converted to 28". I had the calibration orifice and I have had some of the same heads on a SF600, so I have reasonable confidence in the calibration. One thing I did not add in was the temperature correction factor, which would lower the numbers about 1.6%, I just couldn't be bothered. This would apply to all the testing, I made an effort to be consistent in machine temperature.