Flywheel, Clutch & Pressure Plate

To handle the torque and HP of the 351, you need to get a 164 tooth flywheel that will accommodate an 11" clutch (12 3/8" bolt circle). These are readily available from Ford trucks such as F-100, F-150, F-250, F-350 or Econoline with 289/302/351W V-8's and the 300 c.i., 6 cylinder engines from the early 1960's. There are many other years in which these flywheels were used. They are the same for all 351's (C & W) from 1969-1973, and for the 1968 Ford Bronco's with a 289 and 11" clutch. Be careful, there are many applications with 164 teeth ring gear but only 11 7/16" bolt circle, which is a 10" or 10 1/2" clutch.

Also note that Ford small blocks are externally balanced. All 221, 260, 289, 302 and 351 engines prior to 1985 are 20 ounce counterweighted in the flywheel and harmonic balancer. Beginning in 1985, the 5.0L engine counterweight was revised to 50 ounces. If you get a flywheel newer than 1984, you will probably have a huge vibration problem. I got my flywheel from a 1973 Ford F-100. I looked at 4 of them, 3 were in terrible condition. Apparently either the people driving the trucks don't know how to shift or the clutches are too weak, but many I saw at Pick-n-Pull were worn 1/8-1/4 inch deep groove over the entire clutch surface. I don't think you could even resurface them. Clutches are readily available from most auto parts stores. Don't get the old style "long" fingers clutch. Get the diaphragm type.

Bellhousing

All small-block bellhousings after 1965, including the late model 289s, all 302's and 351W, as well as the housing from the 300 c.i. 6 cylinder, will bolt up to the 351C block. The FE and other big block engines, including the 351M and 400 Cleveland, are bigger, have a different bolt pattern and will not bolt up to the 351-C's¹.  The housing from the small 6's (200ci) is significantly different and will not fit either. Before getting a bell housing think about three things; material, linkage and fulcrum.

Bell housings are made from either aluminum or steel. The early aluminum ones are more difficult to find, but the later years are plentiful in the junk yards. The ones from a car with the T-5 transmission will not fit, so don't get one of those. Also, pay close attention to the mounting bosses for hydraulic slave cylinders, the opening for the release arm and the release arm pivot.

 

Bellhousings Steel Aluminum 30 pounds 13.6 kg 7 pounds 3.2 kg

I have noticed that there are several different types of fulcrum (pivot) used through the years. Several that I have (inadvertently) collected are shown in the pictures below. Note also the differences in the opening for the release arm as well.

D1TA (1971, steel)	E0TA (1980, Aluminum)	E4TA (1984, Aluminum)

Linkage

Hydraulic Clutch Components: Master cylinder (top) and slave cylinder (bottom)	Bell housing for hydraulic clutch. Note the slave cylinder mounting bracket on the left side

I put headers on and there is very little room for the stock z-bar. It looked as though it may fit, but I may have to "adjust" the headers with a hammer so I chose to go with a hydraulic linkage. I got a complete bell housing, master and slave cylinder from a 1984 F-150 with a V-8, but the slave cylinder interferes with the headers, so I decided to use a custom hydraulic setup. If you don't have long headers, this may work. Be sure you get the entire setup, as the bell housing has a special flange cast into the housing, for mounting the slave cylinder. One option I didn't use was the hydraulic release bearing because the only ones I could find were hundreds of dollars. I abandoned the stock hydraulic system shown above and developed a custom one using a Wilwood high volume master cylinder (p/n 260-6764) and a Wilwood slave cylinder (p/n 260-1333), both available from Summit Racing. The slave cylinder, which is a pusher type, is relatively easy to attach. The master cylinder requires some thought to mount. For calculations and details of mounting the clutch master cylinder, click here. If you have a power brake booster, it will be in the way and will create more problems. The big problem in using a custom hydraulic clutch system is mounting the master cylinder.

Note: I have not completed the installation yet, so if you use this idea, proceed with caution

This is my plan:

1. Since I don't have vacuum boost for the brakes, install the master cylinder to the firewall using the the hole that the clutch rod used to pass through.

2. Rather than bend the existing brake lines between the brake master cylinder, fabricate new lines that bend around the new clutch master cylinder. Use a tubing bender to fabricate new ones.

3. Make an adjustable sliding link to go on the slave cylinder and connect to the clutch pedal. Details of the design idea are in the master cylinder calculations section.

¹There is talk of some 400-C engines having a small block bolt pattern, but I can't find any firm data, such as block casting numbers, to support this.