crown vic 4.6 swap?

[Mr. Rustypwnz]

First....he realized that 32V means the engine is a 4V. The actual point behind the swap is cutting some serious weight with the aluminum block and adding a pile of compression to the engine by combining the 2V top end and the 4V bottom end. The B-heads do outflow both the PI and NPI heads, but they do so at the expense of added weight and low end torque production.

Second....NPI heads don't outflow PI heads. Maybe after serious porting a difference will be realized, but stock out of the box the PI heads school the old NPI castings. But yes, the cams and intake are trash on the NPI heads too.

well my ported npi set up is eating pi 99+ gt's all day, so i guess im biased lol

still it would make no sense to take off the b heads, for compression pi heads on a mark bottom end is like 11.6-1 comp, yeah mod motors like compression, but detonate that thng a couple times and its over..

 

[srtthis]

Sure its not closer to 13:1? Thought that's where the flat tops would put it...
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[Gearbanger 101]

How would that compare to the 3V 4.6L? I've read it clocks in at 420 pounds fully dressed. That seems pretty light.

I'd imagine there would be a flood of 3V's available in the boneyards with all the 05-10 Mustangs and 04-10 F150's in the boneyards in the next few years.

Seems a nice chunk of weight off the nose and some good performance potential

From what I understand, the problem with running the 3V engine is making it work with the early ECU. One of the guys here dropped one into his '96 (billfisher I think) and had all kinds of trial and error going on getting it to work. Not 100% sure if he ever figured it out or not?

It would be a nice set up though. Almost all the flow and horsepower potential of the 4V, and better low end torque production than a 2V.

well my ported npi set up is eating pi 99+ gt's all day, so i guess im biased lol

That's not that hard to believe. A set of ported NPI's should equal, or outflow a set of stock PI castings (depending on the quality of the port work)....add the little bump in compression to the mix swapping the '99-up heads to the earlier short block, plus whatever other bolt ons you've got done to the car and its no wonder you're showing 99-up GT's your tail lights.

still it would make no sense to take off the b heads, for compression pi heads on a mark bottom end is like 11.6-1 comp, yeah mod motors like compression, but detonate that thng a couple times and its over..

I guess it all depends on what would would consider "making sense"? Like I said, you strip a lot of weight from the nose of the car and just the added compression from the PI heads alone would the otherwise 4V short block right around stock '96-'98 Cobra RWHP numbers. But the torque increase would be considerable. It would make for a fun little street machine, that's for sure. Ad a small amount of nitrous to the mix and beat up on Corvettes all day long.

In any case, they'd better make sure the tank is filled with plenty of hight octane fuel.

 

[Mr. Rustypwnz]

i just really think for simplicity, and not having to build the engine. go with a 97-98 mark or 96-01 cobra engine. the wiring and crap would have me going to rehab, for major drug abuse, but if you like it, go for it..

oh and if you do, go with some 4.10-4.30's you wont be disapointed!!