Well im finally used to the power that the S-Code intake gave me and as usual, I want more. Has anybody actually dyno'd their engines before an RPM intake swap and then after. I have access to a dyno just about anytime I need it, but wanted to know if anybody has done any real life comparisons from the old-school to the new-school intakes.

 

do a search in this forum for intake shootout... this topic has been extensively discussed but that thread shows results for like 7 or 8 intakes i believe....

 

Yeah, but I didn't think that the shootout actually had the S-Code in it. I'll look again, in case im crazy, plus the shootout only covered the higher RPM ranges, thats why I was curious if any of the guys here did it.

 

The big "S" intake is just a plain jane old car 4v intake right? Nothing special. Every FE I've seen from 66 up that's 4V and not a CJ has that intake. I've got a pile of them and scrapped a dozen of them. Is there something I'm missing here? It's a good intake manifold, but not something I'd put on an engine if I was truly concerned over making alot of power or anything above 5000 atleast.

 

nobody has any dyno info that i know of. The rpm will respond nicely to ported heads, or give a boost on stock heads.


The "s" intake is nothing special averagef250!

 

I'd swap intakes just to loose that 50 extra pounds The RPM will work fine, even on stock type engines. Or if you want the same performance you've got now, just get a Performer 390 intake.

 

deffinately don't want the same performance, I'll clean up my heads a bit this summer and hopefully save enough for an RPM, well thats the goal anyways. Unless anybody has one they just want to get rip of

 

I think he means "S" code from the Mustangs and such. Not the 70's intakes stamped S with the EGR port deal....

 

well to clarify Ceets thoghts, yes I do mean the "S" code intake with the large S welded in front of the casting number. Its a 67 intake, thats why i was curious about the performance vs the RPM. Thanks Ceet for the input.

 

What is an "S" code 390 then? Is that a 390 GT? I was under the impression a 390 GT used the exact same intake as everything else. As iron 4V intakes go, I've seen a ton of the "S" intakes which seam to be the same performance as a performer intake and I've seen the iron cobra jet intakes which are about an inch taller and look like a performer rpm and weigh about 20 pounds more than any other FE iron intake. I see the term "S code" used a lot to describe a 390 with a 4V intake that has the "S" on the intake. Can anybody clarify this for me? Thanks

 

The "S" code 390 refers to the GT 390 which came in the 66-69 Stangs and Fairlanes. It seems some are confusing the "S" casting 4 bbl iron intake with this engine. While it may be the one used on them originally, it's not a part that contributed to the higher hp rating. As others have said, it was used on the other "std" 390's as well. The parts that set the GT 390 apart in the higher hp rating was the camshaft, the dual bolt patterned exhaust side of the heads (to fit the engine between the shock towers), and the 600 cfm Holley carb, plus the slightly better flowing exhaust manifolds and dual exhuast. Block, crank, rods, and pistons and in the 68-69's the heads are the same castings the same as others of like years. My 68 Merc's high compression 390-2bbl motor is basically the same engine as a GT 390, just missing the GT cam, 4 bbl carb & intake and had the flat-log manifolds.

 

Thanks. So "S" code is just a grossly over used term for a 390 GT. An FE that wasn't really anything spectacular anyway.

 

The S code works best as a wheel block......

 

Or an anchor

 

Not when compared against the other HP FE's, no. It was still a good engine, and one that's easity duplicated. The 67 FB Stang I had, had one. It wasn't a GT Stang, just the std. fastback with the GT390, 3 speed manual and 3.00 geared 9" rear. It ran high 13's that way. Pulled like a freighttrain. I warmed up the one in my 68 Merc with a Crane 272 degree Energizer cam, 428PI intake, topped it with a 3310 750 Holley, added FPA headers. Swapped the 2.75's out back for 3.70's and it runs mid 14's with the stock C-6 transmission. Not bad for a 4200 lb hunk of iron with the stock bore, and untouched heads and the original pistons.