XR7 Dave
Registered User
No. The 4v actually has a wider power band, but that's not really the question here.
Which engine for my LX?
- Thread starter Mercutio
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EECDOC
Registered User
Will, back in the day (2001ish) I did a bunch of PI head swaps on 95 and up 4.6 Birds. The PI swap really wakes up the early shortblocks as they bump the compression up to the 10:1 range. The PI cams also work very well. Adding a 80mm Maf and a good dual exhaust system plus a custom reflash to the PCM, and you've got a fun and powerful DD. Add to this a good torque convertor, simple J-mod to the trans, and a set of 3.73 gears, and these cars run in the 13's (on drag radials) all day.If your engine is still in good shape, this would be a good bang for the buck.
Mike.....
Mike.....
FrankenBird
Registered User
I dont agree. At all. My bird had almost all the moda you listed plus 24lb injectors lightnine mafs and a porter vic jr manifold and 75mm tbody and plenum, its very best was one.YeS one mind 14second pass. It was consistantly a high 14second car...YeS it was times too, my buddies 98 mark8 has just muffler delete a 90mm mafs and a canned tune and it walker all over my pi swapped thunderturd.
nickleman60
Registered User
racecougar
Registered User
So what stall TC and rear gear ratio were you running?
jdsgallops
Registered User
XR7Dave said:
If I spent $2250 on a set of heads and only made 270rwhp I would be pissed. $2250/30=$75 a hp. Much better ways to spend money IMO. Then again I am not a 4.6 fan in any way shape or form. The AFR/ported cobra intake/ custom cam on my 331 cost well less than $2250 and made way more than 270rwhp though through a 5speed. The "junk" I have on my current daily driver, pro comp heads, explorer intake(both on car when purchased) and the e cam I just installed would cost under $1000 even bought new. Should put down equal or more power. Considering I can pick up an electric die grinder for less than $75, or the cost of 1 hp using the TF heads I would port the PI heads and use the left over money for a used blower setup if I really wanted the power In a daily driver.
Rofl!!
Mike is correct!! Mine was one of the PI ones he put together back in the day. In its stock 96 4.6L form with full bolt ons the car ran 13.90's with the Stock 96 4.6L set up. With the PI swap, tune on drag tires it went well into the low 13's and with a very small stage 1 cam and a bullet intake it went into the high 12's on motor. So there is no BS about it.
I'm sure with a set of PI/TFS heads, maf, gear and some converter the car will run well into the 13's all day long anywhere. I know Mikes work and several cars he has completed this swap on that ran well down in the 13's. Mine is just one of the many.
Mike is correct!! Mine was one of the PI ones he put together back in the day. In its stock 96 4.6L form with full bolt ons the car ran 13.90's with the Stock 96 4.6L set up. With the PI swap, tune on drag tires it went well into the low 13's and with a very small stage 1 cam and a bullet intake it went into the high 12's on motor. So there is no BS about it.
I'm sure with a set of PI/TFS heads, maf, gear and some converter the car will run well into the 13's all day long anywhere. I know Mikes work and several cars he has completed this swap on that ran well down in the 13's. Mine is just one of the many.
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racecougar
Registered User
The power per dollar figure doesn't transmit well across engine families. You know this. If you're going to compare a Modular to a Windsor, you might as well throw the SBC and LS engine families in there, too.
Sure there are cheaper options that will make more power. But making the most power for the lowest outlay isn't and wasn't the point of this thread.
jdsgallops
Registered User
We could throw those other brand x names in there. After all he is looking at doing a non originally installed engine into the chassis of his choice.
As Dave said about the stock cams stock components are hard to beat for daily driver status, mpg, and reliability. If port work on the PI heads only nets 10hp it is still a much more budget friendly alternative than the $2250 for the TF heads. Since Dave only quoted peak power numbers I am curious what the average through the rpm range is. This is the true testament to the potential of the engine. From what I hear the TF head is a bit soft down low. And he has said he sees a wider power band with the 32v head...... Mark 8 engines, really any early 4v engine, can be had for well less than $2250. Is that apples to apples enough for you? About the same power TF vs 32v and the 32v can be found for practically give away prices. We all know what happens when we start modding our cars. When you already have one heavily modified car that you "race" you can take a more conservative approach with the 2nd or daily driver. Exactly why I chose an E cam for my GT while my Cobra has a custom spec.
As Dave said about the stock cams stock components are hard to beat for daily driver status, mpg, and reliability. If port work on the PI heads only nets 10hp it is still a much more budget friendly alternative than the $2250 for the TF heads. Since Dave only quoted peak power numbers I am curious what the average through the rpm range is. This is the true testament to the potential of the engine. From what I hear the TF head is a bit soft down low. And he has said he sees a wider power band with the 32v head...... Mark 8 engines, really any early 4v engine, can be had for well less than $2250. Is that apples to apples enough for you? About the same power TF vs 32v and the 32v can be found for practically give away prices. We all know what happens when we start modding our cars. When you already have one heavily modified car that you "race" you can take a more conservative approach with the 2nd or daily driver. Exactly why I chose an E cam for my GT while my Cobra has a custom spec.
racecougar
Registered User
Keep in mind that the PI heads aren't free. And sure, a used, stock, "B"-head 4V can be picked up for less than the purchase price of a pair of TF heads, but it will also make significantly less power.
jdsgallops
Registered User
I don't know what B head 4.6's go for in your parts but but they can be had around here for under $500. That gives me at least $1750 to spend on performance upgrades on it. And Per Daves reply he stated that the TF heads made about the same power as the 4v engine would. Along with the 4v engine having a wider powerband.......
racecougar
Registered User
I'll let David clear that up for you. A stock "B"-head 4V will be in the 235-260 rwhp range through an auto, depending on which intake and cams you run and your definition of stock. $500 is awfully cheap for a non-clapped out 4.6L 4V. Rebuildable, bare Teksid blocks typically go for $300 plus shipping.
If it's within the budget, the TF heads with a stock PI intake and stock PI cams will handily outperform a used, stock Mark VIII engine.
If it's within the budget, the TF heads with a stock PI intake and stock PI cams will handily outperform a used, stock Mark VIII engine.
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Mercutio
SCCoA Member
Again, thanks for all the responses.
Mike mentioned a J-mod, which is the plan regardless of the engine choice. The car already has 3.73s, so that's done.
David, you said I wouldn't like aftermarket cams. I have no problem with the way my SC idles, so a cam that's maybe a little less aggressive than that would be fine with me--I think. But I have no idea what's popular with mod motor cams these days.
Mike mentioned a J-mod, which is the plan regardless of the engine choice. The car already has 3.73s, so that's done.
David, you said I wouldn't like aftermarket cams. I have no problem with the way my SC idles, so a cam that's maybe a little less aggressive than that would be fine with me--I think. But I have no idea what's popular with mod motor cams these days.
jdsgallops
Registered User
That may be true with a stock Mark 8 motor but I will have an extra $1750 to stick into that "stock" motor. Being I have seen numerous Mark 8's in this area for sale in the $1200-1500 range getting the engine for $500 shouldn't be that hard. A whole car would donate many parts to the swap and the rest could be sold for a minimal investment for parts used. Again you are spending $2250 for 30 hp over PI heads and have how much more room for growth potential?
XR7 Dave
Registered User
Trick Flow has a cam kit that complements the heads. I'd keep to the mild side though since the car is heavy. If you decide to do that let me know, I'm a Trick Flow dealer and can get pretty decent pricing.
racecougar
Registered User
A ton. We obviously have different opinions on the subject. I've done the 4V swap. If I was looking to transform a 4.6L MN12 into a fun driver today, I'd slap a set of TF heads on it and throw a decent TC and gears at it.
The TFS heads are the best improvement that can be made to a 4.6, short of a supercharger.
My TFS head swap was worth .7 seconds, the HP went from 255 rwhp to 312 rwhp.
The TFS cams were used as well.
The above numbers were shifting and trapping at 6000 rpm.
Plus I can port the TFS heads if I want to really run up the rpm.
But if you have allready commited to 4v parts go with that.
The 4V valve covers look sexier.
My TFS head swap was worth .7 seconds, the HP went from 255 rwhp to 312 rwhp.
The TFS cams were used as well.
The above numbers were shifting and trapping at 6000 rpm.
Plus I can port the TFS heads if I want to really run up the rpm.
But if you have allready commited to 4v parts go with that.
The 4V valve covers look sexier.