Cast iron heads

Discussion in 'Fox 5.0 Mustang Tech' started by Project74, Dec 18, 2003.

  1. I have a 79 w/ a nearly stock 302 (308 in reality) and I want to put different cylinder heads on to improve hp, without going to aluminum. What are the best heads to go with? I've heard everything from 351 to late 60's 289 heads work well.
  2. For cheap (I'll assume that's what your after here), it's hard to beat the GT40P heads off of Explorer engines, but be aware that you may need different headers to run these heads. 289 heads are nice for upping compression, but don't flow all that great for a stock head. Heck, I'm sure even the E7 heads off of any 5.0 HO mustang or lincoln LSC motor would be an upgrade over what you have now.
  3. Windsor jrs or srs and mayeb you can find a set of iron trick flows as well
  4. For price/performance balance I am bolting on a set of GT40's (not P's). P's are slightly better but require the aforementioned special headers. Both are supposedly good for 30-40hp over E7's which are already better than yours. Roush 180's/Windsor Jrs are a little more money but reputedly are good for 50hp. the 200's/Sr's are likely to much head for a 308 unless you are seeing 7000rpm. Don't bother with the vintage stuff. A pair of E7's would be better. Also check the other thread for powerheads & thumpers.
  5. No you can get the Mac longtubes to work. Also there are many headers out there that will work.
  6. I have done this to my 79 Capri and my 82 Mustang. I highly recommend the Ford iron GT40 heads. I got one set of SVO new in the boxes from a guy, and one set used from a Lightning truck. Both work great.

    I did a valve and seat prep job on both sets prior to installation, and changed the springs on the Lightning set. The SVO set was on the car for under $600, the other set was a couple hundred more.

    I would recommend this route, or possible some ported E7's such as Thumpers.

    I also did the home port route way earlier, on some 79 style heads. That works, but the chamber volume is still larger than the later or GT 40 units, even milled. Cost wise, if you put bigger valves in, mill them, and change the springs on a stock set, you probably spend the same money as the GT40 or GT40P route would cost and get less performance.

    If you go the old 289 or early 351 route, you also may have to mill the rocker bosses, or change studs, get new rockers, and change the springs, etc, etc, for more costs. Note that the newer type accepts bolt down rockers, and the older ones have pressed in studs that need changing and tapping. I have several sets of those around also, and elected not to use them. To me, finding the 351 heads with the bigger valves was also too much trouble.