302 SO spec question January 16, 2005, 06:19:42 PM Since I have owned my Bird, I have learned quite a bit about the differences btwn the HO and SO motors. Firing order, intake, heads, etc. One big question; does the SO motor have forged pistons like the pre 93 HO's? I am just wondering if I could turn this engine into an HO with parts addition alone. It only has 64K on it. I am curious simply because I have seen mostly engine swaps vice upgrades. I just hate to throw away a seemingly healthy shortblock if it isn't necessary. Quote Selected
Re: 302 SO spec question Reply #1 – January 16, 2005, 06:51:12 PM The earlier SO 5.0's did have forged pistons. I believe all 86's and 87's had em. not sure on the 88's. Keep in mind they are flat tops and deppending on the cam/head combo you want to run, this may prove to be a problem. With stock E7 heads and a stock HO cam it will clear though and with the flat tops you will actually have a slightly higher compression ratio (about 3/10ths or so.) Quote Selected
Re: 302 SO spec question Reply #2 – January 16, 2005, 07:06:44 PM I have a '86 HO flat top piston 5.0(Pistons are stamped F6ZExxxx, you may want to check yours)... Just Bolt on a set of Trick Flow heads and be happy, I know I am... Quote Selected
Re: 302 SO spec question Reply #3 – January 16, 2005, 11:32:26 PM well Tom, most reports say all the 86 HO's got flat tops, so that explains your situationas for the forged pistons, as far as i know, all SO's got cast Quote Selected
Re: 302 SO spec question Reply #4 – January 17, 2005, 02:20:21 AM Quote from: Tbird232ciwell Tom, most reports say all the 86 HO's got flat tops, so that explains your situationYes thats right ALL '86 HO got the forged flattops... Point was, the Trick Flows are about the only aftermarket head that will not have piston to valve interference issues with a high lift/duration cam....Quote from: Tbird232cias for the forged pistons, as far as i know, all SO's got cast The '87 5.0 I pulled apart had the same pistons as my HO. Don't know if it was a fluke or not, but it was the orig engine as the cars vin was stamped on the top of the block behind the intake. Quote Selected
Re: 302 SO spec question Reply #5 – January 17, 2005, 11:14:47 AM starting in '87, all S.O. short blocks were the same as the '86 H.O. motors, only difference being of course the cam and everything on top, In '87 the H.O. motors got different pistons and heads Quote Selected
Re: 302 SO spec question Reply #6 – January 17, 2005, 03:15:43 PM now, when you say flat tops, are they completely flat topped, or are they dished, but no valve reliefs?as of now, im thinking about slapping some pistons and rods from any 5.0 with valve reliefs, some E7 heads, then picking up all the nessesary BS i need and just slapping it all in after the TC i on the road Quote Selected
Re: 302 SO spec question Reply #7 – January 17, 2005, 07:20:34 PM Quote from: Tbird232cinow, when you say flat tops, are they completely flat topped, or are they dished, but no valve reliefs?as of now, im thinking about slapping some pistons and rods from any 5.0 with valve reliefs, some E7 heads, then picking up all the nessesary BS i need and just slapping it all in after the TC i on the roadMine are perfectly flat topped, no dish. Quote Selected
Re: 302 SO spec question Reply #8 – January 18, 2005, 08:40:58 AM I have a 1987 5.0 with the stock pistons. If i pay a machine shop to put in larger valves( 1.94/1.68) in my stock E7 heads, will I have piston to valve clerance issues??? Quote Selected
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