Optimal specs for a 351W/450HP stroker motor?
 

I just bought a Superformance roller and want to build the motor myself having built a few Chebys in my previous life. I'm shooting for around 450 to 500 HP and will be using a TKO 600 trans. Currently I'm planning on starting with either a 418 or 420ci stroker short block based upon a 351W and adding most likely either Edelbrock alum Performer heads or Victor Jr heads, probably a Torker ll intake, 780 Holley and MSD ignition. With the 60cc Victor Jr heads I can get flat top pistons running 12.5 compression ratio or with dished pistons, 10.1 in my short block assembly.

I'm at a loss on what cam and cam specs to run here and would appreciate any suggestions that you might have. Of course I want something with a lot of power but I don't want some totally wild street beast that is going to be a real pain to live with.

What are your thoughts on a cam and related cam specs and what changes in my build specs in general should I consider in order to reach my goal of 450 to 500 hp? What combination of parts do you see here that sounds all messed up? What better combination can you suggest? Unfortunately I’m on a limited budget here so aluminum blocks, FI and other exotic stuff are out of the question. Thanks in advance for any thoughts you could share I need all the input I can get right now.

Honestly? Building engines with that kind of output is not for the garage builder. You can certainly work with a local builder and pick and choose your parts, but building a moderate street engine (especially a Chevy, which is an easier build than most) is one thing, and putting together a high-revving, 1+ HP per cube engine for a light car is a lot more demanding.

Anyone can bolt the parts together. Only those with experience can get the most out of the combination, including a lifespan measured in thousands of miles.

"A man's got to know his limitations." - Dirty Harry Callahan.

PS- 12.5:1 was a wonderful thing back in the days of 102 octane pump gas. You will not be able to drive it on anything but Unocal 105 (at $8 a gallone) or pump 91 with a 'spensive bottle of octane boost in it. Think it through - nearly all of us have about 10-10.5:1 compression for a reason.

Congrats on buying the Superformance Tim!! What color is it?

Agree with Gunner. You probably can't beat a crate motor for the cost/performance. Keith Craft has a great reputation and will work with you on exactly what you want.

http://www.keithcraft.com/ourengines1.html

If that's all the power you want a hydraulic cam will do it. A .580 (or so) hydraulic roller with about .555/.576 .236/.240(110)..and the Vic JR heads and intake will make 525 + with 10.0:1 compression.

We have a couple of 408W in our group making 525 flywheel horsepower with less than 10:1 compression. Check with Keith Craft if you want to buy a motor.

http://keithcraft.com/index.html?404...om/default.asp

or do I like did. I told him I wanted a 302 stroked to 354 fuel injected street motor for my Cobra. I did not want to be embarrassed at the stop light by a Corvette but did not want a race motor. I bought the heads and cam from him. Motor makes 402 rear wheel horsepower and 416 tq. That's about 500 at the flywheel. It's the best cruising motor I've had. Lots of low end torque and fast.
I could have bought the whole motor from him for what I paid for the rest of the parts not counting my time.
With the crappie gas we have today I would think you want to stay around 9 to 1 compression. Keith has build two FE's for a couple of our guys and they are 9 to 1 motors. Over 600 horsepower each and very, very streetable on 93 octane gas.
Dwight

You can make that kind of power easily with 10:1 compression, AFR 185 or Victor Jr heads, Cam with with 575 lift (Comp 282XE is a good one used in the Ford 392 crate engine) and a Victor Jr or Air Gap dual plane manifold. That Torker II is way outdated.

Thanks guys, very helpful information.
 

Thanks guys, very helpful information.

When building a 427 size stroker,don't be shy about putting a good flowing cylinder head on it,especially if using a 4.125 bore. The TFS 225cc Highport head will get you in the ballpark.
Also,if going into a light weight car,like a Cobra,you won't need a dual plane intake. Even with a Edelbrock Super Vic, first gear will be useless,with any kind of throttle pressure,and this is in a 3000 lb. vehicle with only a 3.50 gear!

Hi Tim,
I just dynoed a 408 that produced 491 hp & 515 ft lbs. It's a real workhouse with a mild custom grind hyd roller, Edelbrock heads, 10.4:1 comp ratio forged Eagle rotating asm & Edel Air Gap intake & Holley 750 dp. This engine produced 400 ft lbs below 3000 and peaked at 515 around 5000.... I use this custom grind camshaft on smaller engines with fantastic results. This would work fine in any car and run below 2000 rpm in 5th gear with np problems.

Mike -- that is a good point you have.

There is Driving the car and there is DRIVING the car, -- when you work with your local engine builder you want to verify the conditions you will use the motor.

Race only - Street/Track - Street/Street.

in this way they can tune and build to your expectations, this means going somewhat concervative on some items. This also has a benefit of being somewhat less expensive and more reliable and usable in the long run.

Eagle makes great rotating assemblies under your guidance , I personally like a 351W block with a cast steel rotating assembly, I beam rods with nice pistons (hyperteutec/or forged) that is a 4.00 / 4.030 bore with a 4.00 stroke, with good heads (175-180cc intakes, 64cc chambers like the X303 heads from ford )

I think with a nice intake on there - you can yield about 402ci and have low oil consumption and be very happy with your motor.

Camshaft indexing is very important as well, you want to let your engine builder know if you intent to use the car below 2000 rpm. -- that way they can advance the cam a bit and make it tractable.

my 0.02 cents --

Steve

The cam is the key to almost any engine, SBFs in particular. The way to build an engine is to select all your other parts and then custom-grind the cam to suit them and the intended use. Barring luck, any other approach is going to lead to compromises and performance that's off the desired curve. A custom cam, spec'ed by an experienced builder, is so cheap compared to the alternatives...

I have always used the same process for designing a combination.

First I determine the power level required to accomplish my goals. Then I make sure I'm not spending one devalued nickle more than I have to to get there.

If you need 550 HP to make you happy, you can do that without spending any money on custom parts. You can also double your budget and end up in the same place.

Unless it's a competition piece you really don't need to chase the last 12 available horsepower when your goals have already been met.

It's a hobby.

Tim, here is a 408 that I did for a guy. This is a CHP forged short block, AFR 205 heads and I believe the same cam that Mark mentioned above, all from Mark at CHP. This is on a very honest Stuska dyno with no tuning. I am confident that with a leaner jet config and some tweaking, this could have made well into the 520's.
Note that torque curve from 3k forward :). This went in a Pacific Roadster car, with a TKO 600RR and 327's. It is a fun ride.

http://i166.photobucket.com/albums/u...408DYNO005.jpg
http://i166.photobucket.com/albums/u...408DYNO006.jpg

Rick