Dropping 351 based motor in '65 that had a 289

[TurboSN95]

My friend has a '65 Mustang with a 289. He is planning on going to a 302 based motor, but I'm trying to convince him on the CHP 427 Street Fighter, since he was looking at dropping the same amount of money on their 331. So, can anyone tell me if there are any mods that are required to stuff a 351 based motor in this car? Springs? Cutting? I hope not... I figured since it has a 289, it should weigh about the same as a 351 with aluminum heads.
He was hoping for 400 horsepower (at the flywheel, NA), but I know he'll get used to it and want more, so I figured get the bigger, badder motor, detune it till he gets bored, and then give him all the power later on... instead of getting a 331, being happy for a little while, then wanting a supercharger in a year. Plus the 351 block is stronger and I can't see dropping $6k on a stock 302 block... just bothers me. Any ideas or comments would be greatly appreciated. Thanks guys.

 

[slapper]

I think you'll be really tight with exhaust headers/manifolds--
some of the others with the 65/66 will probably chime in.

 

[dodgestang]

My friend has a '65 Mustang with a 289. He is planning on going to a 302 based motor, but I'm trying to convince him on the CHP 427 Street Fighter, since he was looking at dropping the same amount of money on their 331. So, can anyone tell me if there are any mods that are required to stuff a 351 based motor in this car? Springs? Cutting? I hope not... I figured since it has a 289, it should weigh about the same as a 351 with aluminum heads.
He was hoping for 400 horsepower (at the flywheel, NA), but I know he'll get used to it and want more, so I figured get the bigger, badder motor, detune it till he gets bored, and then give him all the power later on... instead of getting a 331, being happy for a little while, then wanting a supercharger in a year. Plus the 351 block is stronger and I can't see dropping $6k on a stock 302 block... just bothers me. Any ideas or comments would be greatly appreciated. Thanks guys.

You can make 400 Flywheel horsepower with a normally aspirated, normal stroke 351. Putting a 351w into a 65-6 is pretty much a no brainer these days, just order up some swap headers, the right balancer and flywheel for what ever tranny you are running, swap in a larger radiator with staggered in and outs and drive away.....now a 351c on the other hand is little more difficult

If you want to push serious HP though, you will need to seriously consider:
1. Adding front torque boxes
2. Adding subframe bars
3. Adding good traction aids..like Shelby style underriders or better
4. Adding a 9 inch if you plan on more than 400 and/or ever see your self with DOT street slicks or better
5. Upgrading the c4 and or 3 speed to either a built c4 or a toploader
6. Adding front disc brakes (if not there already) and a 2 chamber master cylinder

 

[ap2368]

I just put a Coast High Performance 408W in my '66 Fastback. It's my 2nd 351 swap into an early Mustang. This last time I used the Total Control motor mounts and some Hedman headers designed for the 351 in an early Mustang.

Everything fit into place easily. I think those mounts were worth the $$!

With the right headers, it is a very easy swap to do. Your friend might want to consider the 408. The guys at Coast told me that the 408 will make almost the same power as the 427, but the motor will live a lot longer.

 

[66P51GT]

Check out http://www.windsor-fox.com/ for just about anything you need for the swap. Hedman and Hooker both make headers you need.

Just remember, You can build a motor with all the horsepower you want, but if you can't get it to the pavement, it is a waste of money. Make sure you have the drivetrain that can handle the power (built C4, AOD, Top-Loader, or TKO), brakes that can stop the car (4-wheel discs), and enough rubber out back with a limited-slip or locking rear end that can hook. The widest tire you can fit without flaring or tubbing are 245s and you definitely want to use a soft compound - any drag radial will do.

Sounds like a fun project.

EDIT: Woops... Windsor Fox doesn't have jack for 351 swaps. Got them confused with somebody else. I did find this however...

http://www.mustangsandmore.com/ubb/DanJonesEngineSwap.html

Also, if you need additional clearance around the shock towers, Ford Power Parts has weld in plates that are availabe that allow you to cup the top of the shock towers and get an additional ~1.5" or so of clearance around the spark plugs.

Good luck...

 

[TurboSN95]

awesome, you guys are good! I know a 331 will keep the kid happy, but in the long run I think he'd be happy at local hangouts and car shows saying "Its a 408" or something like that with a ****-eating grin. As far as the trans, rear and brakes go, he does plan on doing disc brakes. The tranny and rear, well, in due time. If the trans goes, then I think he'll just put it away and get a decent trans, same for the rear. The car has been sitting for over 10 years waiting to go into the body shop, hopefully this next week it'll finally go in! Next comes the motor..

 

[dodgestang]

. The widest tire you can fit without flaring or tubbing are 245s and you definitely want to use a soft compound - any drag radial will do....

Just one correction.....with rear drums, you can look on my wheel chart for how to fit a 265 with rolled rear fenders, and with rear disks, you can fit 255s....I have them on mine

You just have to be willing to spring for 17 inch rims, otherwise its 245s

 

[Edbert]

Engine compartments for a 65-66 are only an inch narrower than a 67-68 right (half inch each side)? If thats the case there should not be any issues with changing plugs. Here are some pics of long tube headers on a 351 in a 67...
link to pics

As you can see there is TONS of room between the heads and the shock towers. At least I call it tons of room after years of having a 390 in my 67

 

[66P51GT]

I suggest before cutting, notching, etc... to install the motor and headers first to see how it fits. If you have access to everything then you are good to go. If it doesn't fit to your satisfaction, you can weigh your options then proceed with a plan.