302 & 351 cam swap...tech answer needed

82 GT · 07-11-2002, 08:58 PM

Can someone please explain exactly why when you interchange cams between a 302 and 351 that the firing order changes.

tarmon8r · 07-11-2002, 09:38 PM

i dont remeber why but i remeber how. is seems sstrange that a motor , cam swap that you have change the firing order but the change is just cylinders that are 360 degrees away from each other on the crankshaft, and the firing order follows the cam shaft anyways so...

Mach 1 · 07-12-2002, 02:30 AM

Quote:

Originally posted by 82 GT
Can someone please explain exactly why when you interchange cams between a 302 and 351 that the firing order changes.

Camshafts are ground to a certain firing order. Do you have any idea how a camshaft works? The camshaft can only work in one firing order (open the valve at the right time for one order of compression and combustion)

The 302 and 351 engines had different firing orders, and thus thier camshafts also had different designs.

The newer 5.0 HO engine uses the 351 firing order, but not the older 302.

82 GT · 07-12-2002, 10:26 PM

Yeah, I know how a camshaft works but someone ask me why the firing orders were different when cams are interchanged between the two engines and I didn't know the exact words to explain it.

PKRWUD · 07-12-2002, 10:58 PM

Because the different cams were designed for different firing orders. The 351 and the 302 had different firing orders until 1982. Since then, all the HO 5.0's had the same firing order as the 351's.

But who cares. It doesn't make any difference. You can put a 351 cam into any 302, you just have to set the firing order to match it. That's all.

Take care,
-Chris

07-11-2002, 08:58 PM	#1
82 GT Import Slayer Join Date: May 1999 Posts: 2,241	302 & 351 cam swap...tech answer needed Can someone please explain exactly why when you interchange cams between a 302 and 351 that the firing order changes. __________________ '82 GT 351W (.060)Comp Cams 274* Extreme Energy cam, ported & polished heads w/ 1.94/1.60 valves 10.3:1 flat top pistons,stealth intake, Mallory dizzy,Holley 750dp carb, BBK shorties,Flowmaster exhaust,C-4 with 3700 stall converter, B&M pro shifter,8.8 rear, 4:10's, subframes, electric fan, powermaster alternator, 4 core radiator. Last edited by 82 GT; 07-11-2002 at 09:05 PM..

07-11-2002, 09:38 PM	#2
tarmon8r Registered Member Join Date: Jun 2002 Location: manassas, va Posts: 186	i dont remeber why but i remeber how. is seems sstrange that a motor , cam swap that you have change the firing order but the change is just cylinders that are 360 degrees away from each other on the crankshaft, and the firing order follows the cam shaft anyways so... __________________ 1983 mustang, 393 cubic inch stroker small block, victor jr heads and intake, gold race 1.6 roller rockers. comp cam 304, 244@ .050. .576" hydralic retro roller cam,lunati rods. block was o-ringed,10:1 forged pistons, speed pro fit fit rings, clevite bearings,msd distributor and igniton,be cool huge radiator, black lite electric fan, march underdrive pulleys, mildon deep sump oil pan, mac 1 3.4" long tube headers, 3" dr gas x-pipe and mac exhaust,ARP bolts. car weighs 2900 lbs w/out driver, sub frames, weld wheels, mickey thompson sportsman pro 26 x 10.5 x 15's,#8 fuel line steel braided

07-12-2002, 10:26 PM	#4
82 GT Import Slayer Join Date: May 1999 Posts: 2,241	Yeah, I know how a camshaft works but someone ask me why the firing orders were different when cams are interchanged between the two engines and I didn't know the exact words to explain it. __________________ '82 GT 351W (.060)Comp Cams 274* Extreme Energy cam, ported & polished heads w/ 1.94/1.60 valves 10.3:1 flat top pistons,stealth intake, Mallory dizzy,Holley 750dp carb, BBK shorties,Flowmaster exhaust,C-4 with 3700 stall converter, B&M pro shifter,8.8 rear, 4:10's, subframes, electric fan, powermaster alternator, 4 core radiator.

07-12-2002, 10:58 PM	#5
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	Because the different cams were designed for different firing orders. The 351 and the 302 had different firing orders until 1982. Since then, all the HO 5.0's had the same firing order as the 351's. But who cares. It doesn't make any difference. You can put a 351 cam into any 302, you just have to set the firing order to match it. That's all. Take care, -Chris __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!

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