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  #46 (permalink)  
Old 12-31-2007, 12:29 PM
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Compression update:

I just did a compression test on this motor and have the following results:
1- 197
2- 190
3- 197
4- 197
5- 200
6- 190
7- 195
8- 197

This was with the engine warm, coolant at 180, all plugs removed, carb at WOT, blah blah blah.
Seems to be inline, no?

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  #47 (permalink)  
Old 12-31-2007, 01:16 PM
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Carl, we used a set of ported Edelbrock E-Tecs. Runners were only 208-210 after porting as most of the work was in the chamber.

EZ, can't ask for any better readings than that.
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  #48 (permalink)  
Old 12-31-2007, 02:45 PM
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Quote:
Originally Posted by Rick WI
Carl, we used a set of ported Edelbrock E-Tecs. Runners were only 208-210 after porting as most of the work was in the chamber.

EZ, can't ask for any better readings than that.
Rick we have seen them Vortecs around 216 or 218 on the intake runners which really slows the air speed down.
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Old 12-31-2007, 05:31 PM
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Dynosim

Hi, mate. Hope you don't mind me jumping in but I plugged your numbers into Dynosim and got 347hp@5000 and 414ft/lbs @ 3500. The CR I got was 10.02 not 10.25. I had to assume a few things like a 4.200" by .041 gasket and a .020 deck.

The head modeling is fairly good as I found the flow numbers for it.

The exhaust modeling is only approximate.

The straight line is your engine, the dotted line is your engine with the same cam with a 114 lobe separation as suggusted at the start of the thread.

This is assuming your carb and dis are spot on.

Hope this gives an idea of how it should behave. If you want me to let the computer grunt for a while it will pick out the best cam grind for it. You just have to give me an idea what sort of torque and power characteristics you want.

I found the software to be surprisingly accurate. At first I was dubious about it, but was proven wrong when comparing it to real world dyno figures on some chevy small blocks at work.

The more numbers you can give me the tighter I can make the sim.

Cheers
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  #50 (permalink)  
Old 12-31-2007, 10:36 PM
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Throw a set of Rhoads lifters in it...

http://www.jegs.com/webapp/wcs/store...FSBeagodnDl4Vw
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Old 01-01-2008, 09:24 AM
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Quote:
Originally Posted by ezobens
Compression update:

I just did a compression test on this motor and have the following results:
1- 197
2- 190
3- 197
4- 197
5- 200
6- 190
7- 195
8- 197

This was with the engine warm, coolant at 180, all plugs removed, carb at WOT, blah blah blah.
Seems to be inline, no?
That's some nice compression numbers, better be running 93 octane minimum.
One quick test you could do with your spark timing is pull the rotor off and zip-tie the mechanical advance so it doesn't move then time the car to 30 degrees with no vacume advance. Then dial in your carb idle circuit and take it for a testdrive this way. I bet your throttle response will be OK and part throttle even better. The get your distributor recurved for 20 degrees total advance and play with 12-13 degrees initial timing. With that kind of cranking compression it looks like you could use a little more cam.
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Old 01-01-2008, 10:46 AM
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I don't believe I can use Rhoads lifters on a solid cam.
Based on my compression numbers, I don't think compression is my issue.

I am running 93 octane and I don;t have any pinging issues with my current settings so I believe distributor curving and carb tweaks are my first action items.

I'd like to squeeze out about 385 horse and 450 torque with this engine. Obviously, if I could get close to 400 torque starting at or below 2000 RPM would be sweet.
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  #53 (permalink)  
Old 01-01-2008, 11:20 AM
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Quote:
Originally Posted by ezobens
I don't believe I can use Rhoads lifters on a solid cam.
Based on my compression numbers, I don't think compression is my issue.

I am running 93 octane and I don;t have any pinging issues with my current settings so I believe distributor curving and carb tweaks are my first action items.

I'd like to squeeze out about 385 horse and 450 torque with this engine. Obviously, if I could get close to 400 torque starting at or below 2000 RPM would be sweet.
WOW the 383's we have built have been around 500 on the torque with AFR and the Vortec heads (906) and have been around 450 horse. I would say our leaving alot on the table some where.

Heres a link to one we built a few yeaes ago.
http://www.chevelles.com/forums/show...highlight=DYNO
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Old 01-01-2008, 12:11 PM
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I haven't read every post in this thread, but I definitely would not pay attention to guys telling you to change a bunch of parts.

If this is an engine that has just been installed, you've got to tune it. Ignition timing, jetting and yes, even enough time for the valves to pound into their seat and the rings to seal up.

You've got 409 cubes and plenty of breathing potential and a stick. When you don't have access to a dyno, some trial and error testing and the seat of your pants work pretty good if you have a little experience.

I'll agree on the timing, that you need more advance, and I'll agree with CNC that Vortec heads will not like anything more than 33 degrees total. If you can't smoke the tires by just standing on it, you've got tuning issues or some major malfunction.


I once built a 340 for my little 68 Cuda, and we shoehorned it in in my brother's garage. I had already ran the engine in on a stand, and it was pretty close in tune, however, it would not pull the hat off of your head.

After just merely driving it for around 20 miles, it proceeded to blow the tires completely off the car and almost caused an accident when I tried to haul it down. After a little tweaking of the Thermoquad and some fine tuning on the distributor, I had a 12 second car that knocked down 18 MPG.


Make certain you've done all you can do with what you have, where you are, now!!!!
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Old 01-01-2008, 06:46 PM
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I don't believe I can use Rhoads lifters on a solid cam.

Gale Banks does....
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