Stock Ford 351W 4bbl dyno numbers

[PRH]

Which heads were used for the OP’s build?
Valve sizes? Any porting?

I wonder how the heads/flow numbers would compare to one of the GM 290hp 350 crate motors.
Those have 1.94 intake valves and a cam that’s .450/.460 lift, 222/222 @.050.

[piston guy]

Galon ,
As crazy as it seems you might have made 290 with a stock cast iron 351W 4 barrel manifold instead of the Edelbrock Performer RPM.

[travis]

Galon ,
As crazy as it seems you might have made 290 with a stock cast iron 351W 4 barrel manifold instead of the Edelbrock Performer RPM.

Up until a few weeks ago, I would have said you was crazy. Now...my opinion has changed, at least on a mild engine.

[jasonn]

Galon ,
As crazy as it seems you might have made 290 with a stock cast iron 351W 4 barrel manifold instead of the Edelbrock Performer RPM.

Curious why you say that? Is the rpm THAT bad? I have one on a 408 because of hood clearance.

[piston guy]

Because I tried various manifolds on "stock" iron 351W heads over the last 50 years. The head is the restriction and a bigger manifold "rarely" helps power over the stock intake. Strokers make it worse. Change the heads to something "modern " ( iron or aluminum aftermarket) and the manifold becomes the restriction. Some engines just don't respond like others do to specific changes. I have an RPM air gap on my 408W stroker BUT it has X302 heads which flow more air than a fully ported 351W iron head. Again the manifold is good with the right head.

[NebrRex]

There was an article in Hot Rod magazine in the mid ‘80’s where Jon Kaase was developing 351w packages. A bone stock 2bbl early 351w with stock replacement forged pistons (9.0 compression) and dyno headers made 211 Hp/353 tq. Adding an aluminum ford dual plane intake similar to an Edelbrock 2181/600 4bbl added like 16 Hp. Adding a good 3 angle valve job brought it up to 255 Hp/362 tq. Then a performer type cam (204/214@.050) brought it up to 291 Hp/373 tq.

I’ve built and/or owned pretty much every variation of carbed stock 351w ever made...there was nothing magical about the ‘69/‘70 years. They was all strong off idle, and ran out of steam quickly. In a ‘69 or ‘70 mustang with 3.50 gears, they was typically a low-mid 15 second car. I’d dare say that the early FI version (‘88-‘93), with the FI swapped for a 4bbl intake/carb, was slightly stronger.

Afaik, there was only 2 hft cams ever offered from the factory on almost all 351w’s (other than the Lightning trucks)...one was 195/195@.050, .416/.416 lift, 107.5 lsa, the other was 206/221@.050, .444/.453 lift, 115 lsa. All carbed versions from ‘69-‘87 got the smaller cam whether it was in a mustang or a truck. FI engines got the bigger one until they switched to a hydraulic roller in ‘94. Lightning’s got a 198/208, .416/.445, 114 lsa hydraulic flat tappet cam iirc.

The ‘69 up to around ‘75 or ‘76 had the bigger valves (1.84/1.54) and typically low to mid 60’s cc chambers. They flow better than the later year heads (except for the Lightning’s which had GT40 iron heads), but the engines was choked with a very low profile intake and pretty terrible exhaust manifolds.

The '84/85 351HOs in the trucks had the GT spec cam like the FI trucks.


.