Another cylinder head question

Discussion in 'SN95 4.6L Mustang Tech' started by crashGTR1, Dec 8, 2003.

  1. First of all, thank you to everyone for having patience with me and my questions and giving me truly helpful answers and input. I've decided that I'm definitely doing the headswap once springtime rolls around, but I had a question about the difference between two types of cylinder heads and the effects of porting/polishing on each. I was originally looking at the 'P.I.' heads (, and I know what to expect performance-wise with porting/polishing, new cams, intake, etc. But now I'm also looking at the FRPP/SVO 4.6L GT Cylinder heads ( These are obviously more expensive, but what I'm wondering is how much more of a power gain I would get with these. It says they're perfect for custom porting/polishing and they add 35HP without it, so I'm curious as to whether or not these heads would be worth the extra moneys over the P.I.'s. I've heard that by switching to the P.I.'s on my engine, the horsepower would be more than a 99+ GT with the same setup due to the higher compression rating and flat-topped pistons. So is it even worth it to get the FRPP/SVO's or should I just get the P.I.'s and port and polish them? Please help. Thanks as always everyone. Peace.
  2. Are you going to stay Naturally Asperated or are you thinking of going "blown" later on down the road?

  3. get the PI heads. the extra cost of the SVO heads is not worth it. nott worth an extra $1000.
  4. most likely true.

    What do you want of the car? How much do you want to spend?

    You need to match all the components.

    Exhaust, Intake, cylinder head, valvetrain, cams, fuel system, power adder, etc.

    SVO(now FRPP) heads filled the void for Modular Heads until ported PI heads entered the market. SVO heads are hard to justify because of the price. Haven't seen any Stage III ported SVO heads flow numbers. The ported PI heads flow plenty for most people even hard core racers. I think one of the fastest mod motor cars has a turbo and ported PI heads. ports non-PI heads., port PI heads.
    There are lots of others as well.

    Cams and new springs would complement a new seat of heads. But you need to think about the other pieces, mentioned above.
  5. I'm staying naturally aspirated. I don't really care too much for superchargers or turbos, it seems like it should be last in terms of mods. I want, ideally, for my car to have anywhere from 350-400 rwhp, and around 400-450 lb-ft of torque. Money, not too big of an issue, as I know I won't realistically have this done anytime soon. I just thought if the SVO heads would be that much better, I'd be willing to dish ot more money. Thanks again.
  6. I hear you. I was heading the same direction myself. Except that I wasn't sure if I wanted to stay N/A. That plays a big part in my decisions since I can't afford to "mod-up" to 400hp N/A and then turn around and try it S/C (supposing I wanted to). If money is no problem for you then, first off you are one lucky sob :D , I would go for the better heads if the HP output is that much better. My first suggestion to you is to call Tim at the Modular Ford Powerhouse (770)751-0333 and let him know what your plans are for N/A 400hp. Then start asking some questions about heads and cams. Just a heads up though, it is not going to be cheap. My best guess is that you are looking at around $8-10K.

    P&P heads 1600
    cams 550
    lower intake 1400
    plenum and T/B 400
    Stroker kit 3500
    LTs, X/H pipe, and SS cat back around 1000
    Chip and Tune... this one runs a wide scale 200-1200

    Some of these numbers are rounded up to account for S&H costs and none of them include installation costs.

    I am no expert on this so I am sure some of my numbers are off for someone that has been doing this for a while and has found a "less expensive" source. I would calculate that these mods will get you close to 400hp N/A.

    Using a power adder can get you 400hp with out going as deep into the engine for about the same price. The kit I am looking at costs around $5K for a 9-10psi Vortech, 90mm Meter, 42# injectors, air to air cooler, chip tune with adaptive tech, cooler plugs, and all the extra shop supplies I need to complete the install except for the punch and the tap for the oil supply. Add on the exhaust and I should be right at 400rwhp. I could even see 410-415 if I use a plenum and TB. Pure speculation at this point since I have so few mods on my car right now but I am hopeful!

    Hope this helps a tad.