408 W or 427 W?

[GreenSnakeDoc]

I'm planning pn pulling my 351 W and do a major power upgrade this winter. There's magic in the "427" designation, which will match the side badges of the "427" body style. I bet the 408 W will make more power because it can probably spin faster, but all I'm looking for is a solid high torque engine: no track days or drag racing. I'm looking for previous experience with both engines, with particular emphasis on the 427 W as I know the extra .170 inches of stroke is really pushing the available cylinder space limits, especially since I have a 1970 block that is supposed to be .020" shorter on deck height.

[olddog]

Even though I own a 5.0 stroked to 347, I have never been a fan of going to the maximum stroke on a street engine.

You may want to question if the heads, you plan to use, will breath well enough to take advantage of all those cubes.

[Ron61]

I have had two 351 W, one stroked to 416 and the other 418. No problems with either and they seemed to last a long time as I ran them hard. But the local engine builder tells me he would rather limit them to 408.

Ron

[WildBill3]

408with a stock block thats what K@M told me also ,did you see that thred from Man o War on the 460 small block,all i can say is wow!!!

[geeper]

I have asked the same question as I am in the process of building a 408 also. I was told the longer stroke needed to get 427 cubes will physically limit your cam selection. Something about a needing a small diameter cam. I don't fully understand it but several sources have said the same thing. Guess I will stick with my original 408 build plan.

[bobcowan]

I used a stock block 427W for a couple of years, including some hard track time. A longer stroke will give you more torque, but limits your rpm's due to piston speed. I used a small base circle retrofit hydraulic roller cam. Since you're not planning on track time, I would build the 427. Bigger is better. And there is something magical about a 427.

[enyawix]

Originally Posted by geeper

I have asked the same question as I am in the process of building a 408 also. I was told the longer stroke needed to get 427 cubes will physically limit your cam selection. Something about a needing a small diameter cam. I don't fully understand it but several sources have said the same thing. Guess I will stick with my original 408 build plan.

in the roller and non roller cam 351w? I was thinking about a 427 with f303 roller cam and 1.72 rocker arms for .550 lift

[enyawix]

only shooting for 500hp/tq wheel a dart would be pointless

[David-JBL]

When I last talked to Tony at Keith Craft he told me that with the "Dart" block that the extra cubic inches that the 427 has over a 408 came by having a larger bore and that the stroke was the same in both. If that is the case then I would think that the rev limit would be the same in each. But then again I am not an engine builder. What is the truth?

[enyawix]

can you run turbos on a 427W or are the walls too thin?

[TerrysSPF]

GreenSnake: With your block I would keep the cubes to 408, just to be on the safe side. You can get a reliable 500hp out of a 408 by spending a little money.
There's a place near me called DSS that sells nice stroker kits. A buddy of mine built up his 351 a couple years ago and was very happy with their products and service. I believe their 392 & 408 kits started around 1700.00 bucks (4.0 crank, H-beam rods, custom forged pistons, Speed-Pro Moly rings, Federal Mogul Tri-metal rod and main bearings). He went with a Edelbrock Victor jr. intake and Vic jr. heads and was just under 500hp on the dyno. This year he changed to AFR 205 heads and both his HP and TQ figures went up over 10% right out of the box.
Here is the DSS site in case you're interested: www.dssracing.com

[enyawix]

560 ~ 570 crank will fall about 500 wheel hp

For a twin turbo setup that is not BIG power.

engine specs are:

Twin T04E Turbocharger .50 A/R Compressor, .63A/R Turbine
Air water intercooler 15lbs of boost

1996 Roller 351 block
Comp cam lifters springs etc.
8.8 : 1 pistons
Ford racing 1.72 roller rockers
BBK 75mm throttle body
Ford racing Ported Tubular GT40 intake
Ported GT40x heads
Ford racing 1.72 roller rockers
F303 roller cam (INT. 288° EXH. 288° INT. 0.512" EXH. 0.512" @ 1.72)
custom headers

[Stentor]

560 ~ 570 crank will fall about 500 wheel hp

You will probably need a little more HP at the crank to realize 500 HP at the rear wheel in a typical Cobra.

Do a forum search on "rear-wheel horsepower" or "horsepower loss."

The HP loss to the rear wheels is typically much higher in a Cobra (e.g., restrictive sidepipes).