here goes, do the HO and nonHO motors have the same crankshaft and just different cams for the diff timing, or do the nonHO have diff cranks as well. just wondering because of future thoughts on a new motor project and HO are very hard to come buy in NE WI, and i don't wnat to buy a crank if i don't need too.

 

I know I'll probably get nitpicked on this deal but here I go anyways.......
As far as I can tell, only the pistons and the camshafts are any differant..
So, if your are starting a build and have a 'non' H.O. engine, it's really no big deal..........

 

since the firing order is different, a different crank must be used in order to keep the right strokes in the right place.

 

not entirely true...

 

i asked because i don't see companies specifing HO or non and i know it is possible to change the firing order with just a cam, in theory. also tinman, eversince i came on this site with a 2.3 vert and i saw your sig i tried to get all 3 but now my $500 beater has turned into a $3000 project with new trans and other goodies, so i guess good and fast are for me, but that seems to be the same with every mustang owner eventually

 

If you look at the firing orders, a few of the pistons fire at the same time. The ones that don't fire opposite of one another (e.g. 3 on a HO would fire 6th on a non, 6 on a non would fire 3rd on a HO). I'm actually not sure on the crank, but wouldn't surprise me if it were the same

 

the cranks are exactly the same. on a carb car all you need to change is the cam and the plug wires. On a fuel injected you will need a HO efi setup as the injectors need to fire at the right time too. Also the HO motors are roller cams, so im not sure how the blocks are different, you may need to get a "retro-fit" roller cam for the non-HO block, but you can manage it, or just dont run roller cam, solid lifters are the way to go in a race motor .

 

Yes, the cranks are exactly the same. The reason for this is each crankpin has 2 rods forcylinders on opposite sides of the engine(L or R bank). If you look at the cyl pairs, when one is on compression the other is on exahaust etc. The difference between HO and non HO is that this is switched up on some cylinders. The one on compression becomes exhaust, the one on exhaust becomes compression, that way the same crank is used.
1372
6548 That's the HO firing order pairs

1542
6378 That's no HO. 1,6 and 2,8 are pairs the share the same crankpin but stay the same on both engines, the 3,5 and 7,4 pairs are still sharing the same crank pin, it's just what each cylinder is doing at that time that's switched between HO and non HO(compression, exhaust etc). If it's a non roller block you'll have to get a roller conversion kit if you want a roller, otherwise flat tappet. If it's a roller block you can use either flat tappet or roller cams. The lifter valleys are slightly different. And yes, make sure if you go EFI you use the right computer/cam

 

The 302 primarily used 2 different cranks. Up to 1984 they had a much larger rotating weight and a 58 oz balance. In 1985 Ford changed that to a lower weight and a 20 oz balance. So if you pull the flywheel off of an 84 and put it on an 85 it will throw the engine out of balance. The H.O. and L.O. have the same crank.

 

The crank doesnt dictate the firing order, the camshaft and the timing chain do that.