Can you fit a 440 magnum in 67 mustang body?

Fitting a 440 Magnum into a 1967 Mustang is extremely difficult and not recommended without significant modifications. While it *might* be physically possible, it would require extensive fabrication and engineering. The 440 is substantially larger and heavier than the largest engine Ford offered for the '67 Mustang. You'd be looking at:

* Major firewall modifications: The 440's size will require significant cutting and reshaping of the firewall.

* Extensive bodywork: The engine bay will need to be widened and potentially lengthened. Hood clearance will almost certainly be an issue.

* Custom-made headers and exhaust: Finding off-the-shelf components will be impossible; custom fabrication is essential.

* Suspension modifications: The added weight of the 440 will require significant suspension upgrades to handle the extra weight and power.

* Transmission and drivetrain modifications: You'll likely need a custom driveshaft and potentially a modified or completely different transmission and rear axle to accommodate the larger engine.

* Cooling system upgrades: The 440 produces significantly more heat than the stock Mustang engine; a larger radiator and more robust cooling system are mandatory.

Essentially, it's a project of immense scope and cost, requiring a high level of fabrication and mechanical expertise. It's far easier and more cost-effective to use a Ford big block (such as a 428 Cobra Jet) or a smaller, more manageable engine if you want powerful performance in your '67 Mustang.