Performance difference: 351W vs 354 stroker?

[DAVID GAGNARD]

Unique 289;

Been playing with the Dektop Dyno,did not have all the cam specs I needed,but most,kinda winged it on the rest,ran your engine with open headers,I do not have a scanner (actually I do,just do not know how to use it),so I'll give you a rundown of what I came up with..... As I said early,you have one hell of a motor,can't wait to take a ride,the Desktop Dyno says your set-up tops out at 464 hp @ 6500 rpms,torque is 431 @ 5000 rpms.....pretty damn good I think,I have found this to be within 8% of actual motors that were actually dynoed,some less,but the most off was 8% and the Desktop Dyno is usually over the actual dyn #s....I'll bring the prinout to NPR for you.....

Now the bad news (not really bad)I ran the same set-up,but using the stock 351-W bore/stroke,results were the 351-W put out one less hp @ 6500 rpms,came in @ 463 hp,torque was 2 foot pounds less @ the same rpms (5000)....Suprised the heck out of me,I thought the 351-W would do better and at a lower rpm,boy was I wrong,would love to see similar actual dyno #s on a Windsor and a stroker like yours.....

David

[Excaliber]

It is an interesting question as originally posed:

302 stroked/bored to 354 vs STOCK stroke/bore 351W

Now let me ASSUME both motors would come with similar cam, heads, fuel (carb or EFI) etc.

I would put my money on the 302 for being the better of the two engine choices for overall performance. Street, track, strip.

As the stroke is SO close 3.47 vs 3.50 I'm not sure it would make a big difference either way. So WHY would I go with a 302? Gut feeling tells me it would it MIGHT build rpm quicker and put out more h.p. as well as offer at least SOME weight savings. And I DO suspect 100 pounds is quite possible. Wheres the weight? Crank? Flywheel? Block? Not sure, I just remember reading it was about 100 pounds difference. And weight is EVERYTHING when it comes to racing, especially ROTATING weight!

Ernie

[GTA]

From every thing I've learned the only disadvantage of the stroker is the extreme rod angle takes away from the longevity of the engine.But then again you will not be driving 20000 miles a year. You can't go wrong with the 302 or 351 w. Roger

[Unique 289_FIA]

David:

Thanks for running the numbers on the Desktop Dyno for me. I need to get that program.

I'd be tickled pink with those kind of numbers. My guess is they'll be within the lower range of the 8% difference, which puts it around 425 hp. This would make sense based on the advertised SA numbers and the other mods. My gut tells me there's some power hidden in the carb. Unfortunately, I'm completely new to tuning carbs so I have a learning curve to go through before I can extract that hidden power. Gonna dyno the car soon to get a baseline.

R.

[V-8]

Originally posted by blykins
Also, I can run Desktop Dyno for you too....need cam specs and compression ratio. [/b]

Hey Blykins;
Can you calculate my engines hp too, please?
Spects:
Engine:408w,internal balance,stock 351w block,
Bore:4.030
Stroke:4.00
Rod lenght:6.250
Rings:1/16 1/16 3/16
Comp Ratio:12.2:1
Cam Shaft:Comp Cams mech roller 608-614 lift,242-248 0.050,110lsa
Carb:Holley 750hp series
Intake:Victor Jr. ported and polished
Cly Heads:TFS tw 2.02- 1.60 ported and polished
Ignition:MSD pro billet,MSD 6 al,MSD hvc coil
Exhaust:Headman headers,X-pipe,Flow masters
Rockers:Crane 1.6 ratio roller

THANKS...

[Mike Simard]

Atay, is your cam the Comp 35-771-8? I considered using it myself for a while, it is a really good match for the rest of your motor.

[V-8]

Yep

[69EFIStang]

All things being equal (displacement, CR, cyl head flow, induction tuning length, exhaust tuning length, etc.), the engines will make the same HP & TQ. However, the reality is that the 302 block uses a 2.25" diameter main journal while the 351W block uses a 3.00" diameter main journal, therefore more friction HP will be associated with the 351W. Additionally, the 302's shorter 8.2" deck height reduces the runner length of the intake manifold by just over an inch than the 351W, biasing the induction system's Helmholtz tuning effect of the 302-based motor to make it's peak TQ and HP at a greater RPM than the longer-runner 351W. So, the 8.2" deck height motor wins the peak HP and TQ battle vs. a 9.5" deck height block of the same displacement, CR, etc.

-Scott