You can pick up a copy of 'Desktop Dyno' for your computer, it's supposed to be accurate within 5% of actual engine dyno results.

 

Well it is quite true that there are many people who would much rather simply walk around and say "my car has 450 horsepower" and never get it dynoed because IMO 99.9% of the time the numbers told by a dyno are significantly lower than expectations and ignorance is of course bliss.

Then again, the reason to go to a dyno isn'treallyfor numbers on a paper, it is to tune the car; to understand where the performance was and how itis changed with some tweaks/changes. A good dyno tune session can net gains from 20-40-60-80 HP depending on how bad your car was setup. I know the second time I went to a dyno I was at 325 rwhp and after a couple hours (and carbs, timing setting, jet settings) pulled 396 rwhp.

You can accomplish similar things by taking your car to the track for a test and tune day. This will allow you to dial in your entire combintation. The first time I took my 65 to the track I started at 17 sec 1/4 and left at 12.4 in the 1/4 because I had some shifting issues and linkage setup issues in the transmission that needed to be ironed out (as well as some driver experience issues).

 

I definately understand that..

 

Im guessing your torque should be a bit above 375, because i do believe they came with a stock 380-385 on that year ...

So my guess in 380 ...

you should really consider that new aluminum intake manifold + 4bbl carb ... swap! .. it would make a good difference!

 

Oh,, Im going with a 4bbl carb/intake,, Just not until i get the suspension and rim/tires replaced. Probably a Weiand Stealth intake with a holley street avenger 570cfm or Edelbrock Performer intakeand600cfm carb

 

the 250 hp rating was gross hp used up till 71, then for the same engine using sae methods like we use now it was rated at 153 hp. With the 2bbl , 8.7 comp and performer cam I'd say its about 200-225 hp, with the intake and carb it should be about 250 hp, add some headers and exhaust and you should be about 275-280 and 330-340tq.

I had a 351w dynoed, it had 9.1 comp, 194 160 valves, ported exhaust and valve bowl work, headers, comp cams 268h cam, roller rockers, performer intake and holley projection 670 tbi and a jacobs ignition and it made around 325 hp and 385 ft lbs of tq.

 

If you put a Street Avenger on you might wanna go with the 670, it'd match a 351 better, especially if it gets heads later. And with some good heads, you could prolly put out close to 400hp at the flywheel.

As far as dyno tuning, I don't like it for vacuum secondary carb setups, sometimes the secondaries never open all the way up and you tune it improperly. Mech secondaries or efi can get good power gains, but sometimes cars pick up power on the dyno, but lose time at the track. Again, a dyno is just another tool for tuning, my view is tune for best performance that you want(mileage, et, top speed, whatever your goal) and use the dyno to understand how you car responds to changes in it's tune. Dynos are great tools though, you can actually see hard data on changes in tune without having to sit in the pits for an hour waiting to run down 1,320ft of asphault for a few seconds [>:]

 

you could bolt on any head on that combo and no way it will make 400 fwhp, the edelbrock perf rpm package with a way bigger cam, rpm int,750 carb and headers makes 400hp/412 tq at the FW, performer numbers are also on the site but not hp, tq is around 335 peak (fw) and drops off fast, I had the performer cam/intake and headers (I was dissapointed) before I did the swap to other parts I dynoed and it was a huge difference. I'll say it again the performer cam is not good in a 351w except in a heavy truck, its too small for any real performance, it is great for fuel economy though.........

 

Well I was under the impression that we were talking about HP at the flywheel, just as an engine would be set up on a dyno....

I will agree with this statement, no engine in the world will make that car generate any fwhp at all, without major revisions to the car....

 

I think part of that though is that the Edelbrock Performer/RPM head is too small for a 351. They use the same head in the 302 RPM package with a roller cam and it makes 385hp, almost 400 with efi. The W makes over 50ft-lbs more though, but only 15 more hp. I think Edelbrock needs to make a bigger Performer/RPM head for 351 and stroker engines, it jumps from a 170cc intake port RPM head to a 210cc intake port Vic Jr head with nothing in between. AFR 185s, RHS 180, Dart 195, Canfield 192 etc, all would make much better power on a 351 than an RPM head would, and still be just as drivable. You are right about the performer cam being small for a 351, the performer 351 cam is even small for a 302 [>:]