351w into 65 coupe

[snake009]

I know this has probably been covered plenty of times and I have searched heaps online and found a bunch of info to help me.

But I find it's always best to ask for input from people who have actually done the conversion.

I'd like to hear from people on things to expect and what difficulties they had etc.

I've got a 65 with a 289
I'd like to get a 351 and someday stroke it to 408

The car has been fully overhauled, suspension, wilwood discs, etc just need some real power.
Will the C4 auto be strong enough for a 351? I'd probably go to a manual once working/stroking anyway but just to get things going would be easy to stay with the C4 temp.
What kind of horsepower is the limit on the C4 and the standard 8" diff?
Do I need to change the engine mounts to something stronger?
I read some people use a torque "strap" ?

Other than that I know I'll need headers that will allow the 351 to fit.

Am I missing much else?

 

[65coupe408w]

I would suggest using the Ron Morris adjustable motor mounts. They lower the motor in the engine bay which is good for center of gravity and also for hood clearance as the 351w is a taller motor. I havent needed a torque strap with these mounts, I think the urethane bushings help alot with handling the motors torque.

Also, note a good set of headers such as Hooker Super Comps are a must, but are a real tight squeeze in the engine bay.

From my understanding the 8inch rear is good to about 400-450 hp. For me I knew I was going to end up with more power than that so I switched to a 9inch.

I know that C4's can be built really strong but I am not sure what sort of power a stock one can take. I personally switched over to a G-Force built T-5.

The only other thing I would suggest is upgrading your cooling system. If you going to 408ci (like I did) thats a 50% increase in capacity so you need to account for that in your cooling system. For me I put a big crossflow aluminum radiator up front and havent had an issue in the 100 degree FL summers.

If you have any more questions let me know, Im more than happy to assist.

 

[67GTCOUPE]

I would suggest a Griffin NASCAR radiator. Go buy a stock car racing magazine and you can order it from some vendors there or get summit/jegs to price match. These are VERY tough and cool with ease. They have 2 rows of 1" alum tubing. They are AFFORDABLE, unlike the custom fit ones. YOu can get different sizes...just measure and I fabbed frame mounts from rubber ford truck rad mounts I got from the scrapyard, then I simply fabbed an aluminum top mount from sheet aluminum.

As for the rear end.....I have an 8 " behind my 393 that is est at 525hp at flywheel.....it is dying. I run 225 street tires and the rear has held up, but it is getting louder...so I can sense that the backlash is getting bigger from distortion of the center section. If i used slicks/drag radials....it would EXPLODE!

I am contemplating using a 8.8" rear end. They are pretty damn tough, and MUCH cheaper than a 9". If they can hold up to 8 second cars....they will do OK for me.

 

[rbohm]

as long as you dont run slicks, and drive like you are in don garlits company car, the stock C4 and the stock 8" rear end can handle around 400hp consistently. run slicks, drag radials, and at the track every weekend though, and i would recommend something stronger. since you are planning a stroker motor, and you can easily get 500hp from a 408w, i would recommend upgrading to a 9" rear end, and a lentech built AOD with a full pressure valve body, that way you dont have to worry about getting the TV cable adjustment perfect as it becomes a kick down able like the C4 has, plus you get the benefit of an overdrive.

 

[mtaqua]

depending on heads and headers ron morris mounts may require some mods, as mine did. Though I was able to move my engine back a little more than an inch.

 

[snake009]

How is changing spark plugs with the 351? I read it's a total pain.
Also, do you need a set of headers that are purpose made for the conversion (close fitting) to squeeze between the strut towers?
I've got a set of long tube hooker headers at the moment on the 289 would be good to keep them..

Any engine bay photos / power figures?

Thanks for the replies

 

[dennis112]

I can change all the plugs in my 393w in 20 minutes. Nothing too hard about it if you have flexible hands and the right tools. Proper header selection can make a difference.My primary tools end up being a shortened 5/8" spark plug socket using a 3/4" wrench on its head for turning.

You WILL need conversion headers. There is practically zero percent chance that a 289 header will work without extensive modification of it or the shock towers. Header fitment is tight. That is the toughest part of the conversion. Here are my Accufab conversion headers:

Dressed to look like a 289 (old photos):

 

[65coupe408w]

^^^^^Sneaky! I like it!

 

[D Durden]

Wow, I just browsed in here to ask a 351W in a ’65 question, and this was on top, so I thought I’d wade in.

I put a 409W in my ’65 coupe way back in 1994, and it’s still in there. It’s about 500 horse (back then) and is probably still well over 400 years later.

Here are the problems I’ve seen and solutions (if available):

1. Mounting the motor isn’t an issue. Get some of the recommended motor mounts and it goes right in. It’s a bit “bigger” but nothing major.

2. I got the purpose built headers. I think they work great and are a great buy.

3. I did progressive rate springs and good shocks. I also did a 4 wheel disc conversion.

4. With regards to brakes, to the best of my knowledge no one makes a GOOD power booster/MC package that fits well. I don’t mean that you can’t fab/cut/reweld/improvise/modify and make something work. I mean there’s not P/N 357-1-X-FITSDURDENSCAR that you can easily use . . . that I know of.

5. Keeping a mild 351W cool isn’t a big issue. A good aluminum radiator will do it. A good cross-flow will easily do it. BE WARNED, THOUGH, if you get into the 408 world with lots of horsepower, it gets tough as lots of the “bolt in” kits are about 1” too thick and are made for 289/302 combos. There is a company out of Cali that builds a unit that is supposed to be blessed by the angels, but they have a horrible reputation and are a huge risk. I’m about to try an off the shelf unit with some minor mods, and I’ll post it if it works.

6. I’m an old-timer and I run a toploader and a 9” Versy. I blew my C4 “Cruise-O-Matic” up enough that I made the swap (in 1988) to a toploader, and it’s still untouched in the car. I’m on clutch #2, and it’s solid. My 8” was holding okay internally, but I did break the housing once. It was a cheap reweld fix. That being said, a local dirt racer changed his mind on a project, and I literally tripped over the Versy in his shop. He was a shop teacher and could make anything readily for himself, so he just wanted the Versy out of his way. I got it for something like $100 complete . . . in ’93. If I were you, I wouldn’t risk an old “Cruise-o-Matic” blowing on you. If you have a modern, well-built C4, you might can do it. If you have the original one, think “oh heck no”. Look for a modern C4 or manual. I figure everyone knows, but I’ll repeat it: a C6 doesn’t fit well, and I don’t figure anyone here would want to mess with an FMX like way back when (although, lol, I have one put back from years ago with a friend).

Other than those things, doing the Windsor swap is the only way to go for easy performance . . . until Ford makes us a narrow “Hemi MDS” that will fit in our cars. *sigh*

 

[67GTCOUPE]

Keeping a mild 351W cool isn’t a big issue. A good aluminum radiator will do it. A good cross-flow will easily do it. BE WARNED, THOUGH, if you get into the 408 world with lots of horsepower, it gets tough as lots of the “bolt in” kits are about 1” too thick and are made for 289/302 combos. There is a company out of Cali that builds a unit that is supposed to be blessed by the angels, but they have a horrible reputation and are a huge risk. I’m about to try an off the shelf unit with some minor mods, and I’ll post it if it works.

Like I say......Buy a NASCAR style Griffin Aluminum rad.....many vendors in the stock car racing mags sell them.....summit will price match too.

These are AWESOME, my 393w stays at 180 PERIOD.

I got mine for $197.00

Fabbed some mounts...added a fan shroud off a aerostar van (cut it down a bit to fit with grander).

You DO NOT need to spend $500-600 for an aluminum rad.

 

[Stangninjak]

I'll chime in. I run a 65 Notch and a 351w. I never dyno'ed it, but I would wager I am at about 375~400 or so...My stats are in my sig.

I run a FoMO radiator from the 289 HiPo that use to be in the car and a 180 stat...no probs so far, I sit at 190ish and I live in S. Florida. I have considered going to a 160, or perhaps getting one of those aluminium jobs as I would like to be at 180 temps.

I had a Top Loader, but after I went to a rack I took it out and tossed in a C4 w/B&M Mega shifter. If you are going to try a C4, do yourself a favor and do not get anything Pre 70...A 69/under is just not going to cut it behind a 351w. Trust me, I know. I have one from a 74 Vega in there now, built up with the goodies, with a "A" servo. Holding up well.

I have a 9' rear with a open diff. I plan to change it our soon. The diff that is. My future plans is to redo the rear shocks, and perhaps the front springs. I have just finish rebuilding the front end with all Scott Drake parts and Open Tracker (?Name) mods. She rides good now.

As for the 351, I run Headmans mid tubes, and a 3inch It was measured at (2 /3/4....lol) H-pipe. Its tight as hell, but it fits.

 

[SitDown]

If you're in the market for the Ron Morris Adj mounts, I have a set w/ std and lowering brackets... Only a couple weeks old.

 

[blown65]

If you end up buying a C4 you may as well spend a few dollars more and get a PA C4. I've ran the crap out of mine for years now and its held up just fine.

 

[rebel65]

That's a testimonial I'de listen to.

it can be a tight squeeze, every one of our stangs has gone through a whole lot since ~'65.
mine was a tight fit, and a little massaging was required. I could prolly get at my spark plugs but with the headers i selected it's a tiiiiny bit difficult, take me longer than 30 minutes I bet.

I also used the stock motor mounts so mine sits a litttle higher, but.. I don't mind I love my cowl induction hood anyway.

 

[65coupe408w]

here's the 408w with headers installed in my 65 fastback...crappy cell phone pic but its coming along well...

before headers:

After headers:

Im hoping it should be alive and running in a couple of months!

 

[snake009]

Looks great.

What headers / where did you buy them?

 

[65coupe408w]

Looks great.

What headers / where did you buy them?

Thanks! They're hooker super comps 351w swap headers with 1 3/4" primaries. I bought them from Summit, minor clearancing is recquired.

 

[Wicked65]

In my opinion, the best thing you can do for a 351 swap is the mustang 2 front end. I kick myself every time i have done major work in my engine bay. Especially if you ever want to run after market heads that have a higher exhaust port.. AND ESPECIALLY!! if your running head studs.. Because you will have a nightmare of a time getting the heads off.. That $500 bucks i saved doing my coil over setup instea

d of mustang 2 is cheap at this point. lol

 

[craig3x]

this may be a dumb question, but I'm a noob. Will a 351 fit in a '65 with the stock hood?

 

[D Durden]

Absolutely . . . I had one with a decent manifold and a Holley 4bbl that fit under a stock hood. You need a fairly small (short) air filter. That's about it.