Hi guys i just got the dyno desktop 2,000 program sent to me from my buddy and i was playing around with it just checking to see what kind of curve i should expect out of my new motor and such and i was highly surprised to see the power it said it should make.

Anyways heres the motors specs and what i entered:

the motor is a 1986 305 lg4 block, it has 416 head castings (no flaming me for building a 305 plz it's free and has barely no miles).

Anyways this is the planned build up:
i plan to port and polish the 416 heads and install 1.94/1.50 valves and stiffer springs, new hardware and 1.6 full roller rockers(not set in stone). I plan to gasket match the ports and gasket match the heads to the manifold. I also plan on the comp cams xe262h grind cam (still not set in stone). The manifold will be a weiand stealth dual plane setup. The exhaust will be 3in from headman elite headers to the rear.

anyways the info i entered on the dyno program was the following:

Chevy 305 engine block with the stock stroke and bore (will probably end up with a very slight overbore but, that shouldn't xchange it a lot). For cylinder heads i had to guess as they didn't give me a choice of a comprable head so i tried the gm882 and the vortec as my guess (remember these heads will be ported and bigger valves installed so i think vortec stock flow should be fairly comprable (could be quite wrong here). I picked 1.94/1.50 valves. i picked a compression ratio of 9.0 to 1 (this is a complete guess i'm sure this could be off a full pnt in either direction which would probably make a mildly significant gain or loss). for induction i have dual plane typed in and 500 cfm 4 brrl flow (may end up with a demon 525 carb if i cant get the tuning down for tb (shouldn't be a problem (i hope). for exhaust setup i entered large tube headers with mufflers. For a cam i entered comp cams xe262 hydraulic flat tappet design.

sorry for such a long post but, you realy do need the details.

anyways it gave me a peak of 314hp at 5,500 rpms and a peak torque of 344ft lbs at 4,000 rpm. it pulls about 300 ft lbs or more torque from 2,000 rpms up on the graph. either my head choices were way off or this program is way off i'm thinking....

Any input or advice is help t/y for your time.

 

Here is what I get with the stock LG4 8.6:1 compression ratio, 1.5:1 rockers, XE 262 cam, headers, a full exhaust, a good intake, and an Ultimate TBI moded TBI (490 CFM @ 1.5 in/hg pressure drop)

RPM--------HP-------TQ
2,000------119------312
2,500------150------315
3,000------182------318
3,500------213------319
4,000------238------312
4,500------247------288
5,000------240------252
5,500------220------210

That is more or less on par with the testing that Car Craft did on their engine a while back. They used a 600 CFM carb and Single plane Edelbrock victor jr. manifold though.

Give your a 454 TBI that flow 660 cfm @ 1.5 in/hg on a manifold such as the performer RPM or Holley Projection. Build it with 9.5:1 Flattop Pistons. And you get this.

RPM--------HP-------TQ
2,000------125------328
2,500------158------332
3,000------193------337
3,500------225------338
4,000------253------332
4,500------266------310
5,000------264------278
5,500------248------237

Now for the final step, port your heads to the 224/160 CFM I got out of a pair of 601s keeping the 1.94/1.50 valves.

RPM
2,000------124------325
2,500------159------334
3,000------197------345
3,500------236------354
4,000------273------359
4,500------305------356
5,000------328------345
5,500------337------322

 

thats more like what i was thinking. Thanks a lot awesome response i appreciate it. i may end up going roller cam and with a holley 670 tb but, we will see.

any idea what a ported 416 with 1.94/1.50s woud do with that cam on stock internals with 1.5 full roller rockers?

 

nvm i answered my own question this motor shold be a trip it seems + that means that my dd2000 gave something close to what you did so i'm happy that i now have a free program that gives mildly accurate readings.