360 magnum possible output?
Well here goes another engine dyno. guestimate question, at least it isn't a sbc that can be searched. This is a budget build, and hopefully I can do it without breaking 2500-3000.
I have the block in the shop going .060 over, able to maintain stock deck height.
Here are some of the parts that I've chosen to use if possible. I have done most the calculating so hopefully it wont be too hard to calculate everything.
I'm pulling some weird numbers out of engine analyzer, so here is whats going into my engine.
I found a rotating assembly kit that I think is a decent deal, Eagle p/n 20501.
- .060 over (4.060 bore)
- 3.580 crank (cast)
- 6.123 I-beam rods
- -5cc. forged flat tops w/ dual valve reliefs.
Correct me if any of the info. or calculations listed bellow is wrong;
- 9.599 deck height from factory
- 4.060 bore
- 3.580 stroke
- 6.123 I-beam rods
- -5cc pistons
- .040 head gasket compressed.
- 1.670 pin height
- Compression Ratio
* 64cc--> 10.39:1
- Deck clearance--> .016
- Engine size--> 370.8
- Rod ratio--> 1.71:1
- Max rod angle-->17*
Cam is Comp. Cams 20-746-9 (info copied off summit)
-Cam Style -> Hydraulic roller tappet
--Basic Operating RPM Range --> 1,200-5,400
---Intake Duration at 050 inch Lift ---> 216
--Exhaust Duration at 050 inch Lift --> 224
-Duration at 050 inch Lift -> 216 int./224 exh.
--Advertised Intake Duration --> 265
---Advertised Exhaust Duration ---> 273
--Advertised Duration --> 265 int./273 exh.
-Intake Valve Lift with Factory Rocker Arm Ratio -> 0.506 in.
--Exhaust Valve Lift with Factory Rocker Arm Ratio --> 0.506 in.
---Valve Lift with Factory Rocker Arm Ratio ---> 0.506 int./0.506 exh.
--Lobe Separation (degrees) --> 114
-Computer-Controlled Compatible -> Yes
--Grind Number --> XR265HR-14
-factory 64cc heads (140 casting, r/t heads); in the shop getting ported, stock valve size, 5 angle valve job. factory flow chart is listed below;
lift--- Intake --- Exhaust
.05-- 34 ---- 24
.10-- 70 ---- 62
.20-- 137 ---- 111
.30-- 181 ---- 142
.40-- 209 ---- 163
.50-- 211 ---- 168
.60-- 211 ---- 171
-M1 aftermarket Intake manifold w/ upgraded 58mmX2 throttle body (1200 cfm.), short ram intake, 30lb/hr injectors (showing a 82.8% duty cycle @ 5500)
-1.6:1 rockers (factory)
-After market headers, y pipe, 3 inch single exhaust w/ cat, Flow master super 44 muffler
let me know if there are any more info you need to run this, Its not looking right in my eyes, not for as little work as I feel it is, maybe I'm just underestimating everything.
The results I'm getting are;
502 ft/lbs @ 4100rpm
452 hp @ 5700rpm
*edited for head data
Last edited by Eric63M; 08-26-2010 at 08:31 PM.
Installing the cam straight up will close the intake valve @ 38 degrees ABDC and result in a DCR of 8.964:1 on Keith Black's calculator. Sounds to me like a little too much squeeze for pump gas. Choosing a closing point of 48 ABDC (adding 20 degrees total to the intake duration over the cam you have chosen, but using the same 110 ICL) would yield 8.381:1 and allow operation on pump gas. The timing for such a cam might be 8/48/60/4.
I would run a DynoSim on this combo, but have no idea of the flow of the heads.
Be careful buying the Eagle crank. Others on this board have expressed disappointment with the machining tolerances. They may have it fixed by now and they may not.
Thanks for the reply Techinspector1,
I've edited the post with the factory non-ported flow numbers, pulled them from a Mopar magazine that was a few years old.
I know the cam is highly recommended on another forum I'm on specifically for the vehicles, a lot of the members are running them without problem, what about offsetting the cam timing?
Thanks for the warning about eagle though, I will look into this.
I think I figured it out.
I'd forgotten to program in the timing curve, it was running a total of 46* @ 3600 (***?), just using the stock flow charts, keeping the same cam.
447 ft/lbs @ 4875
438 hp @ 5575
Showing very pump gas friendly also, looked around and was able to find slightly thicker copper head gaskets @ .049 compressed, dropping the compression to 10.2:1, may be slightly lower but that will depend on how much material is taken out during the bowl blend.
The numbers make since now, everything across the charts look good, and I should be able to keep almost everything off my old engine (intake, distributor, injectors, throttle body, short ram, exhaust). Tuning should be fairly easy with only needing to turn the injector duty cycle and pulse width up slightly (thank god for the SDS system I purchased).
Thanks for the help,
OK, now I see how you are able to run that short cam with the 10.39 SCR, the heads don't flow that well, so will not be able to pack the cylinders to the point of detonation. Makes one hell of a torque motor.
RPM HP TQ
1500 111 387
2000 161 424
2500 203 427
3000 245 430
3500 301 451
4000 341 448
4500 371 432
5000 380 400
5500 369 352
Peak volumetric efficiency 92.2% @4500
Peak BMEP 183.6 @3500
I wouldn't increase the gasket thickness. You'll need all the squish you can get.
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