I've got $1500 to spend on either a used 4.6L or new cylinder heads.
I found a 4.6L from a 99 GT with 37,000 miles at a local junkyard for $1250. My current engine has 100,000 miles. Sean Hyland Motorsport sells the complete PI head package(intake and cams included) for $1350.
Which would be better to do? Get the heads and rebuild the engine later? Or get the engine? I intend to supercharge it in about a year.

[ScottHalliday]

I would find out how strong your current engine is before deciding which path to go. I would start off by getting the oil pressure checked and then a compression test.

Is there any reason you feel the engine is weak or needs replacing besides the miles? When you start racking up miles on an engine, alot of things affect how well it holds up and here are just a few:

* What type of miles were they. Highway miles is far better than stop and go around town. * Was the engine pampered or well used and abused * Were frequent oil/filter changes and maintenence always done. *Was the engine ever really overheated or run low on oil for any length of time.

IMO, if the engine proves strong, go with the heads otherwise if it is feeling under the weather and not up to some serious abuse, replace it.

Hope this is of some help and good luck with your decision.

[David L Gary]

If the '99 engine is a PI, absolutely go with a complete engine. All of the spare parts alone, or the sale of your old engine is worth money. When you put your foot in it(like all good v8 mustang owners do) you are takeing the chance and engine or something will break.

I would also do the complete engine also, if you can swing the swap.The 99 and up engines are so much stronger and your end results would be more positive after you add the power adder.

[StalkerStang]

Especially if you want to add a blower to it, 96-98 short block+99 up cams/heads/intake will result in a 11:1+ compression ratio which is not good for street blower applications. The reson the compression is higher is the 96-98's use flat top pistons while the 99 and up blocks are dished.

The cheapest place I can find to install the engine quoted me $1000. I don't have enough to get the engine and have it installed, too.
Is there a way to lower the compression on the 96-98 block with the PI heads?