Alright guys, another mechanical question that may sound stupid but I gotta know. My brother and I are getting ready to assemble my 351w over the next couple weeks. We were talking about cams. Apparently he has a stock 72 302 cam with minimal miles on it. Other than the firing order, what pros or cons would there be to installing the 72 302 stock cam in an 84 4v 351w ? Thanks, Darrel
i don't think there's much difference. i've used cams that are for either. just change the firing order. i guess it does give you a wider choice of cams. if anyone else works on your engine you'd better let them know if there's a difference.
i don't really think it makes a difference. but someone who micro manages may tell you one way or another is a better firing order. lift and duration is still going to be the same either way.
I don't think the lift and duration are quite the same, but its not a big difference. 351W timing is a bit different due to the longer stroke, at least on the early years. A true gearhead might notice a *slight* difference in engine performance, but not much. 351W cam is a bit bigger, that being said, any aftermarket cam will do better in either engine.
I strongly suggest getting a performance cam and saving the 150 dollars on something that can be changed out much more easily (carb, headers,accessories) that way you can save it back up and do a bolt on upgrade later instead of pulling the top and front apart in the car to change a cam later.
Compairing the same cam in the two different displacments, you would see the torque increase in the larger engine but the peak hp 'may not' be any higher because the cam airflow (looks) to be less in the larger engine and becomes more of a restriction to air flow. Usual rule of thumb is to increase cam duration about the same percentage as the displacment increase for general non performance average use. But putting the 302 cam in will still run ok but is really a waist for performance because all you gain is from the larger engine displacment and it even gets a little restricted using that cam.
Funny this came up. No one has mentioned that the reason Ford changed the firing order on 351s, then 302s was because the new firing order put less stress on the bottom end. Are we ready for that arguement? Chebbie guys have even found power on the dyno, smoother idle, and less stress on the block/crank by going to this firing order! Comp sells a whole line of cams for the Chebbies in this order. They put a lot of R&D into it, just as Ford did I am sure. *I need to note, for those of you that might not know: The Chevy FOs are the same as the SBF. The "new" Comp cams FO is the same as the Windsor/5.0s And don't argue the numbers aren't the same! If you transpose Ford cylinder numbers onto a Chevy, then follow the FO, they are the same. Just numbered on the banks different. Ready for the arguement! Dave Btw: Here is a paste of Comps catalog summary... COMP Cams® 4 & 7 Swap Firing Order COMP Cams®, the leader in cam technology, is proud to introduce 4 & 7 swap firing order cams for Chevrolet solid roller and flat tappet applications. These cams provide an exceptionally smooth torque curve and a significant decrease in crankshaft deflection. COMP Cams® 4 & 7 swap cams require no additional engine modifications and are available in Chevrolet Small Block and Big Block applications. The 4 & 7 swap firing order cams have been dyno and track tested in a variety of applications. Customers have reported an increase in horsepower over traditional firing order cams.
quite true. in fact, look at the #1 cap on a 289,then the front main on a 289 hipo block. hipo is visibly beefier. then look at the 302 block #1 cap. same as 289 hipo block. when they slightly altered the cylinder length for the 302 block, they also tried to help withstand the added stress on the front cap.
Ford found when they built the 351W that the #1 main bearing was getting beat up so they changed the firing order and kept the same recipe for the 5.0. Made a difference in the NVH (noise, vibration, harshness) ratings of the engines, too. As for the cam Ford usually didn't change timing for different dispacements in the same engine family. But if you look at timing specs for good aftermarket cams you can see where they will take into account one engine's longer stroke over another. Performer RPM cams for 302 and 351 have the same lift and duration but the seat timing, lobe separation, intake centerline are different. That's why I run a 351W RPM cam in my stroked 302/347.
Also is the old arguement of no 7 cylinder plug wire leaking into no 8 and causing it to fire to soon. Ford did a recall on some older ford trucks to correct this problem. I personally think the 351 firing order runs smoother but to each his own
Good post for Boss9 You have made a pretty good arguement to the original poster for NOT using a 302 cam in his 351. I also just realized that the only bottom end failure I have ever experienced in a 302 was front main bearing failure. Probably coincidence, but food for thought. Dave
