4.6 SOHC SVO head ?s

[fastangboi]

Sean Hyland recomends these heads, but it is a straight bolt on for 96-98 but requires modifications for fitment on a 99-04. Its hard to run down these heads and they cost $899 each.
Intake flow is [email protected] vs PI [email protected] (cfm)
Exhaust flow is [email protected] vs PI [email protected] (cfm)
Chamber volume is .53cc vs PI 42cc
Intake port volume is 173 vs PI 159cc
My ?s are

Are these heads worth it?
if they are, does any one know the modifying involved?

I would also be planning on p/p these while they sat in my garage, so im sure i could squeeze slightly bigger numbers out of them.

 

[RandyStinchcomb]

they are hands-down the best SOHC head on the market. they are $$$ but worth it. the valve location is better than other SOHC heads and they come wth larger(then stock) S/S valves. they have the tear-drop shapped intake port which meens you can use your stock non-Pi intake or get the matching SVO intake from Frpp, also $$$. now wth some intake port matching, they can be adapted to the square port design used on 1999 up heads/intakes so you can used the Pi intake or a Bullitt intake. I have these heads on my GT and they make HP

 

[fastangboi]

Are they better than Patriot? And yes i read the part about "best on the market", but thats kind of wierd that Ford could make a head in 1998 that is better than current after market.

And wouldnt throwing a non-PI intake on my 00gt hinder performance a little?

And i might be wrong but doesnt the SVO 4.6 intake manifold look like the Bullit?

Im just trying to get info before i make a serios purchase.

 

[RandyStinchcomb]

Are they better than Patriot? And yes i read the part about "best on the market", but thats kind of wierd that Ford could make a head in 1998 that is better than current after market.

And wouldnt throwing a non-PI intake on my 00gt hinder performance a little?

And i might be wrong but doesnt the SVO 4.6 intake manifold look like the Bullit?

Im just trying to get info before i make a serios purchase.

1st off, stay far, far away from patroit as they have had tons of quality control problems wth there heads, try Jason @ Steen Racing for some of the best modular heads, oh and do not be fooled by "flow #'s. the Pi heads and the Bullitt intake were both modeled after the SVO stuff, so I can't speek for FoMoCo as to why they do **** ass-backwards. yes, putting a non-pi intake on a pi head would choke the engine.

 

[TGJ]

1st off, stay far, far away from patroit as they have had tons of quality control problems wth there heads, try Jason @ Steen Racing for some of the best modular heads, oh and do not be fooled by "flow #'s. the Pi heads and the Bullitt intake were both modeled after the SVO stuff, so I can't speek for FoMoCo as to why they do **** ass-backwards. yes, putting a non-pi intake on a pi head would choke the engine.

I agree with Randy on this, stay away as far as possible from Patroit heads as you can. Yes the Bullitt intake is based on the SVO( FRPP ) intake, but the FRPP( SVO ) heads have more in common with the NPI heads, than they do with the PI heads. Steen or Renegade Racing can port match the SVO's so that the match the PI intakes. I don't know of anybody else that can do it but I wouldn't want anyone but those 2 doing it for me. I prefer Jim over at Renegade over Jason, but I know you will be looked after by the best if you go with either.

 

[Dope 97GT]

I agree with Randy on this, stay away as far as possible from Patroit heads as you can. Yes the Bullitt intake is based on the SVO( FRPP ) intake, but the FRPP( SVO ) heads have more in common with the NPI heads, than they do with the PI heads. Steen or Renegade Racing can port match the SVO's so that the match the PI intakes. I don't know of anybody else that can do it but I wouldn't want anyone but those 2 doing it for me. I prefer Jim over at Renegade over Jason, but I know you will be looked after by the best if you go with either.

+1 on renegade, Jim gave me lots of good info and he may still have a set of svo heads sitting around because I am thinking of getting them if he still has them in the winter. I have the svo matching bullitt style intake manifold and from what I hear the svo heads are about the best performing 2v heads.

Hopefully I get some money and am able to purchase these heads and get them on my NPI so someone on these boards will have them and can comment on the numbers.

 

[fastangboi]

This is kind of confusing.
So from what i gather the SVO head and intake were made in 1998 specificly for the nonPI motors. But ive read that the bigger cc for a combustion chamber will lower my compression. But this helped the nonPI some how, and ive read not to use these heads in a forced induction situation.

so seeing how this combo was designed for the nonPI guys will i just not see as much gain. like if a nonPI guy jumps to 300hp(up 85hp), will i only get like 330hp(up 70hp)? i mean its a big jump, but just not as much.

Ive also consitered throwing this on a bored Teksid block.

pipe dreams......

 

[fastangboi]

and from what ive read the SVO manifold flows more air. and if you go to the Accufab single oval blade TB, porting the SVO wont mess with the idle quality. Single blade on a bullit will mess with the idle.

 

[TGJ]

This is kind of confusing.
So from what i gather the SVO head and intake were made in 1998 specificly for the nonPI motors. But ive read that the bigger cc for a combustion chamber will lower my compression. But this helped the nonPI some how, and ive read not to use these heads in a forced induction situation.

so seeing how this combo was designed for the nonPI guys will i just not see as much gain. like if a nonPI guy jumps to 300hp(up 85hp), will i only get like 330hp(up 70hp)? i mean its a big jump, but just not as much.

Ive also consitered throwing this on a bored Teksid block.

pipe dreams......

The SVO heads outflow the other heads. On a NPI car, there will be no compression change when swapping to SVO heads, the gains that they see are because of the improved flow. PI heads increase the compression on NPI and that is part of the power gain when going swapping PI heads. Just a note, I am referring to just the heads, not PI cams and PI intake.

You will lose compression with SVO heads on a PI motor. I am not sure if you will see a gain going with stock SVO heads over PI heads without a tune. You will lose about 10 - 15 RWHP in the compression loss, you will see a gain from the improved flow, how much I don't know and whether or not it makes up what you will lose. You will need 91 octane fuel and the timing curve moved significantly and you should see more gains by doing this. The reason is that SVO heads are a slow burn head, NPI and PI heads in stock trim are a fast burn.

Some will say you shouldn't use SVO's for a FI application. Some will argue that they are only good for a race application. For a street car that is going to be more of a track car than a street car, the SVO heads are probably what you want but you will need to build a motor around them. For a street car that is going to be a street car first and track car second. You would be better off with a set of P&P PI heads from Renegade or Steen.

 

[TGJ]

and from what ive read the SVO manifold flows more air. and if you go to the Accufab single oval blade TB, porting the SVO wont mess with the idle quality. Single blade on a bullit will mess with the idle.

Actually a ported Bullitt is better than a ported SVO intake from what I have seen. A tune will easily fix that idle issue with the Bullitt.

 

[TGJ]

+1 on renegade, Jim gave me lots of good info and he may still have a set of svo heads sitting around because I am thinking of getting them if he still has them in the winter. I have the svo matching bullitt style intake manifold and from what I hear the svo heads are about the best performing 2v heads.

Hopefully I get some money and am able to purchase these heads and get them on my NPI so someone on these boards will have them and can comment on the numbers.

Those SVO heads at Renegade are likely my old SVO heads. I didn't use them for my car as my car will only see 91 octane fuel as that is the highest I can get here. To take full advantage of the SVO head, you really need higher octane than that and a very aggressive spark curve.

 

[Dope 97GT]

Those SVO heads at Renegade are likely my old SVO heads. I didn't use them for my car as my car will only see 91 octane fuel as that is the highest I can get here. To take full advantage of the SVO head, you really need higher octane than that and a very aggressive spark curve.

I can get 93 and i have a good tuner here in NY. My car is not a DD either actually havent drove it in about 2 months but usually just on the weekends so It would make a nice track car.

 

[RandyStinchcomb]

This is kind of confusing.
So from what i gather the SVO head and intake were made in 1998 specificly for the nonPI motors. But ive read that the bigger cc for a combustion chamber will lower my compression. But this helped the nonPI some how, and ive read not to use these heads in a forced induction situation.

so seeing how this combo was designed for the nonPI guys will i just not see as much gain. like if a nonPI guy jumps to 300hp(up 85hp), will i only get like 330hp(up 70hp)? i mean its a big jump, but just not as much.

Ive also consitered throwing this on a bored Teksid block.

pipe dreams......

well the SVO heads and intake came out in early 1996 not 1998, I got mine in late 1996.

now using them on a P/A car is not an issues as Jim Travers uses the SVO heads on his D/R car which Steen Racing did the motor and heads and his car has run 9.00's in the 1/4

doing the Teksid block would be a good choice, thats what mine is based on

 

[TGJ]

I can get 93 and i have a good tuner here in NY. My car is not a DD either actually havent drove it in about 2 months but usually just on the weekends so It would make a nice track car.

93 is better, but I was thinking along the lines off 100+ octane.

 

[stangGT97]

93 is better, but I was thinking along the lines off 100+ octane.

wow so these heads are really not designed for a DD huh? That's too bad, I thought I finally had a direction for my motor, now I'm back at square one. Thanks for all the information!

 

[Dope 97GT]

wow so these heads are really not designed for a DD huh? That's too bad, I thought I finally had a direction for my motor, now I'm back at square one. Thanks for all the information!

I bought some parts from a guy who uses them on a dd with no problems nice car too.

I can get over 100 octane at the track I go to as well.

 

[TGJ]

wow so these heads are really not designed for a DD huh? That's too bad, I thought I finally had a direction for my motor, now I'm back at square one. Thanks for all the information!

I didn't say that. The heads will work in a DD car, it is that they are more prone to knocking than a set of P&P NPI or P&P PI heads that are still a fast burn head and that hinders the SVO heads on the street.

I would have no issue running SVO heads in my car on the street. If you consider running SVO's on the street, I suggest getting a hand-held tuner with 2 tunes on it. One for the street and one for the track.

 

[CENTENNIALSTANG]

revive!!!! will ported SVO heads work well with a turbo?

 

[RandyStinchcomb]

absolutely yes