since it's time to replace the head gaskets and basically all the top end gaskets.. would it be worth the effort to swap out the stock heads and RV cam for the GT40P heads and a E303 cam?

reason being, i have both of these parts sitting on my shelf from my 351W engine swap i'm doing in my SN95 mustang.. along with enough parts to throw another engine together..

 

No to the E303. It has no place in a truck.

Regarding the GT40p heads, do you have headers that will clear the spark plugs?

 

i know i would have to change the firing order, but i didn't know if i would get any benefit from the cam. as for headers, i have pacesetter shorties.. i may have some bkk's shorties laying around somewhere..

 

You would have a surging idle because your '89 has speed density and your powerband would be be sluggish on low end because your truck is much, much heavier than a Mustang.

Generally speaking, Mustang cams in trucks are a bad, bad idea. Mustang cams are for lightweight vehicles since it doesnt take much power for to pull on low end. What pulls hard in a Mustang is the direct opposite in a truck.

Truck cams are built for more low end torque since they are much heavier than cars and need the extra power to get going.

There are other options that are much better.

 

Since you have an SN95 Mustang, if you still have the stock 302 cam, you could install that in your truck and advance it 4 degrees and have something respectable.

 

i do not, bought the car with the E303. i do however, have a stock 351W cam (i believe it's stock, no markings) out of a 94..

 

I would look up the stock specs on that 351W cam and see what they are. More than likely, that's better than the stock 89 cam.

 

Having just done that, I would suggest you find a set of exhaust manifolds and get them cleaned up and new studs installed ahead of time. Also new or cleaned up bolts.
Actually what I did was pull all the intake parts off a junk motor, cleaned everything up, sprayed some paint, wire wheeled the bolts etc. so that once I tore it down all I had to clean up was the gasket surface on the block and start bolting things back together.
Sure made everything go faster and smoother.

 

Stock 351 Roller Cam Specs

Exhaust Advertised Duration (Deg): 263 Degree

Exhaust Duration At 0.050 Inch Lift (Deg): 197 Degree

Exhaust Valve Lift With OE Rocker Arm Ratio (In): 0.446 Inch

Intake Advertised Duration (Deg): 273 Degree

Intake Duration At 0.050 Inch Lift (Deg): 185 Degree

Intake Lift With OE Rocker Arm Ratio (In): 0.421 Inch

Valve Lift With OE Rocker Arm Ratio (In): 0.421 Intake/0.446 Exhaust

My thoughts: I'd run the hell out of this cam. It looks good to me.