[Sfinch]

I have a 1965 mustang coup it came with a i6 motor i want to put a 351w with a t5 trany. will i have to cut out anything to make it fit other than the motor monts and trany monts. will i have to move the fire wall or anything like that. thanks guys for all the help

[silver 4.6]

im almost sure they didnt change the body back in 65 for different engines.. would have taken to much time/money.

motor mounts and tranny mounts, probably.

good luck man

[sixtsixstang]

I believe the deck hight of the 351 is taller than the 289/302. You will have some problem with the shock towers, especially if you go with headers. I'm sure it has been done, not sure what mods you will have to make.

[brianswyatt]

the block is wider at the exhaust ports and you will have to cut up the shock towers to fit the 351. You did not ask for my opinion, however, I would go with the 289 or 302 option. I like them stock but you could stroke a 289 to a 347 and have a really hot engine at less weight and avoid cutting up an increasingly valuable car.

[thetvirus]

I believe the 351w fits in easy no cutting involved and tons of people have done it, only problems are hood clearance depending on which intake and air cleaner is used and header/exhaust manifold clearance of the shock towers. I think they make special headers to fit on a 351w in a 65-66 mustang, or I think you can use 289 hi-po manifolds.

[1966er]

I'm still learning these Fords, but, I thought the 351W was pretty much the same as 289/302 as far as sbf go. The 351C the is bigger engine.

[sixtsixstang]

The deck hight on a 351W is higher than a 289/302. This pushes the heads up and closer to the shock towers. I'm sure it's possible with the right parts, but your clearances will be very tight.

[Cobra6]

Originally Posted by brianswyatt

the block is wider at the exhaust ports and you will have to cut up the shock towers to fit the 351.

You DO NOT have to cut shock towers to install a 351W or 351C.
The 351C is tight, but it will fit with the correct header applications.

[PaulS]

I have made the swap to a 351W into a 66....
With a C4 there are factory headers that will fit. Changing plugs is tight but easily done. With an Edelbrock performer four barrel manifold hood clearance is close but it does fit.
You will need the V-8 frame horns, 289 mounts, and a belly bar.
The T5 transmission is another matter. I believe you will need to fab a new crossmember to locate the mount and the driveline may need to be made to fit. You will need to cut a hole for the shifter - not a big deal but you will have to locate it to fit. I have found no headers that fit with a toploader four speed so I am making my own. (there are some shorty headers but don't expect any better performance than with stock exhaust manifolds (that don't fit anyway)) You may not have problems with a T5.
The only reason to shave the shock towers is to add clearance for getting at the spark plugs.
You are going to need to fab clutch linkage for the T5 - probably hydraulic or cable - I would go with the hydraulic so headers can be more easily fit.

[andrewmp6]

Both 351 will fit its a tight fit but fit with out any cutting to the car.But adjustable motor mounts would be better to get it prefect in there.For headers Ford Powertrain Applications or JBA Performance Exhaust New Product:: '64-1/2 to '70 Mustang Headers and Exhaust Systems are the best out there but not the cheapest.

[RF Mustang]

What PaulS says is exactly true! Absolutely No problem to make the change to the 351W in your 66. However, the trans crossmember for the t5 will need to be fabed up or you can buy it from most any mustang supply house.

He's right about the headers, the cheap hooker # 6901 HKR are made for a 351W in a 64 - 73. Be prepared to have to beat them around a little. Anything other than a long tube header you might as well keep stock exhaust manifolds on the car. 351W stock exhaust manifolds are considered the poor mans header anyway.

Personally, I would do the hydraulic clutch set up as well (as you will have Z-bar issues) but i would get a better fitting header if money allows. Like the Hooker super competiton plus or like i have on my 351c Dougs Headers. Dougs headers have a heavy 3/8" flange and fit absolutly perfect. of course for as much as they cost, they better fit perfect.