Should I Replace Manifold Before Dropping My Engine?

chapters707

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Jul 13, 2014
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Hi all, I am getting ready to swap out my busted 96 4.6 sohc engine with an identical one in the next week or so. (Been struggling with a stubborn midpipe bolt.)

Anyway I've been reading today about a common problem with these plastic manifolds leaking coolant and eventually cracking. This new engine has about 110k miles on it.

So my question is would it be advisable to upgrade to an aftermarket one with aluminum crossover (or possibly a PI one if this is possible?) While I've already got the engine sitting in my garage on a pallet? I assume it'd be much easier this way as there's really nothing in the way.

I'm not really in a good spot to drop money on new pi heads and cam right now but is there a way to use just a pi intake and still reap some HP gains with the stock heads and cam?

Anyway as always any input is much appreciated, thanks for reading.
 
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wmburns

SN Certified Technician
Aug 14, 2009
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Why aren't you using a whole PI motor for the swap?

It's always easier to perform motor work on the engine stand.

However, if the $$ just isn't there, then sometimes you got to do with what you have got.
 

chapters707

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Jul 13, 2014
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This is my first swap so I wanted to keep everything as simple and straightforward (and inexpensive) as possible to avoid any compatibility issues. Is there a way for a PI manifold to sit properly on our stock heads? If not then would you recommend a manifold like this one with an aluminum crossover while I still have the engine out of the car and can more easily install it myself?

View: https://www.amazon.com/ATP-Automotive-106002-Engine-Manifold/dp/B00PH99P3C/ref=sr_1_1?s=automotive&ie=UTF8&qid=1477365934&vehicle=1996-54-688-39--7--7-3595--1-1-713--3-0&sr=1-1&ymm=1996%3Aford%3Amustang


It would just suck to get this new engine dropped in and hooked up only to find I'm losing coolant at the crossover. I've heard it is a very common problem for these cars...
 

wmburns

SN Certified Technician
Aug 14, 2009
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Houston Texas
This is my first swap so I wanted to keep everything as simple and straightforward (and inexpensive) as possible to avoid any compatibility issues. Is there a way for a PI manifold to sit properly on our stock heads? If not then would you recommend a manifold like this one with an aluminum crossover while I still have the engine out of the car and can more easily install it myself?
Sooooooo if simple, straightforward, and inexpensive are the primary goals for a motor swap I don't see how one could go wrong swapping in a WHOLE Romeo PI motor. To me that seems much more straightforward than using a non-PI motor and trying to make major modifications. Due the the age of the non-PI motors I suspect that they really aren't cheaper in the salvage yard either.

Further any later model year PI motor will come with the updated metal coolant crossover. <presses the easy button>

Are you aware that you could use a motor from a 2001+ Crown Vic, Grand Marquis, or Town Car?

But it's your project.

If looking for easy, safe, straightforward then I would NOT try to install a PI intake on on non-PI head.

I still stand by my earlier comments. It's almost always easier to do motor work on the stand than in the car.

If looking to perform a fix that will last, then use an intake with a metal coolant crossover.

But there are tons of cars on still on the road with the all plastic intake. The plastic intakes are much less likely to crack if the coolant system maintenance is kept up. Don't let the system get low on coolant!
 

chapters707

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Jul 13, 2014
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Fair enough, I probably should have done more research before I ordered the engine...too late for that now haha. I'll have to check it out tomorrow when I go to work on the car and see if there are any visible cracks or signs of leakage on there. If it looks iffy I'll just order a new $200 manifold and know it should last a long time after that.

Also the cooling system should be in good shape after this because I got a brand new aluminum radiator and overflow tank to install with the engine! (Overheating is what blew up the original one) Hopefully once I get it all installed it will run really nice. Thanks for your input I appreciate it.
 

soupnutz

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May 23, 2009
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Pretty easy and common to swap just the intake. Been a while (about 10 years), since I've done it, but I want to say you use PI gaskets and you need to apply rtv around the front coolant passages. If you're interested I have a PI intake with aluminum crossover already drilled and tapped for use on a nonPI engine. I have PI heads and cams also. You can install the PI cams on npi heads for a power bump. Shoot me a PM if interested.