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Old 11-02-2008, 09:29 AM
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351W Advice

Just have to say great site, just recently joined.
Had a couple questions on a 351W I going to build this winter for my '84 Ford 1/2 ton. Most of my engine building was SBC in my younger days, not too much on the Fords other than basic overhauls. The truck is going to be mostly a daily driver and used to pull a 16' car hauler. It has the 351W HO in it now. Looking for low-end power, no high rpm racing or anything like that. The truck already has true dual exhaust and I picked up a set of full length headers for it. Was thinking of keeping the stock Holley 4bbl. Any ideas on an intake manifold that might help me out with the low end power better than the stock one? Probably changing cam and lifters, just going to pick one that the power band suits my needs. Also thinking of tossing the stock ignition and going with an all-in-one HEI unit for simplicity. Probably keep the stock heads, just a 3-angle valve job and some pocket porting. Don't want to spend a fortune on this.
Was wondering if I have to change pistons what comp. ratio I should strive for? Want to stay away from any detonation problems with pump gas. Any other advice or suggestions? Thanks for now.

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Old 11-02-2008, 09:39 AM
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The 1984 W engine used heads from a 302/5.0 with only 124 cc intake port volume, which flow about 155 intake and 110 exhaust.
Plan all your mods around this very pronounced LACK of intake/exhaust flow.
You are looking at a power level below 4500 rpm maximum.

I suggest following CompCams recommendations for 4x4 cam, etc.
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Old 11-02-2008, 09:52 AM
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I could probably live with that rpm peak for what I'm using it for. Know offhand of a different year stock head that would be better suited? Didn't really want to start buying aftermarket ones. $$$
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Old 11-02-2008, 10:16 AM
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Quote:
Originally Posted by tc882000
I could probably live with that rpm peak for what I'm using it for. Know offhand of a different year stock head that would be better suited? Didn't really want to start buying aftermarket ones. $$$
NO.
The 69-74 heads with the fat 18mm spark plugs have 144cc intake ports and 1.84 valves..... but they do NOT have hardened exhaust seats for unleaded fuel. They are still barely adequate volume for a 289 cubes.
(by comparison, most 350 Chevies have heads around 165 cc from the factory= more potential)

Rebulding heads with seats, guides, and bigger valves and bowl porting will cost $5-800 hundred dollars.
Build around what you already have.
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Old 11-02-2008, 10:38 AM
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sell the 351W and buy a 460....

4000lb truck +5000lb trailer load = a HUGE increase in TQ acceleration force is needed....

the stock 351W is designed for (almost) the most low end TQ acceleration force possible with 351 cubes by using the tiny 302 heads for max velocity/best possible cylinder fill when the piston speed is slow....
it has about 320ft/lbs at only 2,000 and 340ft/lbs peak at just 3200...

don't confuse HP power with pulling/accelerating power which is TQ....

and within reason, basically cubes=TQ power!!!
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Old 11-02-2008, 10:47 AM
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351w

The gentleman is right.... sbf &sbc are not great truck motors.I have a 351w-1969 in my 57 RWagon.If your towing that much , get a 460.Mabey a different truck?Deals are out there.
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Old 11-02-2008, 10:54 AM
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To answer another of your questions.

The SBF is detonation resistent with the good squish/quench design of the pistons and closed chambered heads.
Strive for 9.0 on static compression and
set up for actual .040-.050 piston to head clearance
and detonation will be non existent with the proper timing.
I prefer the multi spark units... MSD my favorite.
Be sure your distributor is not worn out.
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