easy performance upgrades on a 351W
 

1994 351W (f150 flareside)

what kind of fuel economy and or horse power/torque can be expected from a throttle body spacer?
It looks simple to make, has anyone here made there own?? (how thick?)
any info would be nice on that subject

also what would be involved in making my own cold air intake? (how to do it)
and what kind of performance gains could I expect with it?

Zero and Zero, this is a classic marketing gimmic that does absolutely nothing on a multiport efi motor.


The stock intake is a real cold air intake, most of the K&N type things you see convert this to a hot air intake, which will actually hurt performance and milage. If you want an improvement here find an intake snorkle from an I6 or 460 truck, it goes from the bottom of the airbox to the large hole beside the rad instead of over the top of the rad, and it does improve airflow.

Now if you want to make performance improvements you can actually feel and measure start with the exhaust system, the more of it you can replace the better and longtube headers will deliver substantial gains. The next thing that needs addressing is the camshaft, if you don't want to dig into the motor consider adding 1.7 roller rockers, this is a relatively easy bolt-on job.

thanks for the info,
so those 2 options are more of a "just for looks" upgrade?

I guess I can just replace the tube going fromt the filter box to the throttle body with a crome one if thats the case

what does the 1.7 roller rockers do?

You wont see any noticeable gain in power with a 460 inlet swap. If anything, increase the base timing a few degrees, that'd be a good start.

As Matt suggests and I tried to, there really isn't anything that restrictive on the intake side of the motor, anything you do here will really only be for looks so don't spend more than what that's worth to you. The key points of restriction on these trucks are the exhaust and valvetrain, opening the exhaust and the valves a little more will help the motor breath better and produce more power. This is what the rockers do, the stock ratio is 1.6 so 1.7 will produce more valve lift. On it's own this won't make a dramatic difference but couple it with other similar mods and the gains begin to stack up. The timing bump is another thing you can do for free that will make a little more power.

If you install 1.7 roller rockers then keep a shim kit handy. It is not uncommon to need shims on a 351 unless the rocker arms have an adjustable cup.

The exhaust upgrades will make a good increase indeed. And if you experience any wheel hop then invest in a set of traction bars to keep from snapping and axle and/or driveshaft.

quick question, wouldn't the intake be restrictive? On mine it was maybe 5" wide and 1" tall... I wouldnt think there would be enough space there for the motor to get the air it needs.....