Engine Bay with Engine
 

I've heard many different opinons to this question.

?What is the biggest engine you can put in a 66' Stang Coupe without having to alter any of the bay area?

I understand that you can fit a 351 in there with just having to change the headers to make it fit. I heard you can put a 427 like the old cobra's in there as well. Is all this correct?

The engine bay of the 64-66 mustangs is pretty small but readily accepts small block engines like the 351W. Now, a 351W can be properly machined and fitted with a stroker crank to yeild cubic inches up in the 427 range (thought I had seen a 434).

However, I don't think the old FE block engines (352, 390, 427,428) nor the 385 series engines (429, 460) will fit without a serious fight.

So the answer I am going to give you is yes, you can get a 427 small block in there, but not a 427 like the old AC cobras.

This is very true, any bigger than a 351 and you'll have to cut down the shock towers. I have a 351w set up in mine and believe me, The hedmen headers are a ***** to deal with! about 1/4" of clearance between them and the shock tower. Doesn't make changing spark plugs easy either.

As thunderbolt mentioned, I think your best bet for more cubic inches would be to stroke the motor. If you do go with a 351 engine like this though I would suggest getting ceramic coated headers. You'll likely be changing out starters fairly often without them. Also, get a radiator from Mustangs Plus that has the passenger side top inlet and the driver side bottom outlet. This part was crucial!!! These engines can overheat easy,... especially with the dinky size of their radiators. Good luck!

Hey Matt, Do you have any pics of your ride that I could look at.
zfrederick@cox.net

yeah,...i gotta find em though, heres one that ive posted before.

FE
 

Ford had to widen engine bay in '67 to get the FE 390 in. As previously mentioned the 65-66 will take only the small block without modification of the shock towers. The 392W crate engine is what turns me on a little. 430 HP out of the box.

Rev