428 into a highboy
Thread Starter
|
Freshman User
Joined: Feb 2018
Posts: 49
Likes: 1
428 into a highboy
Hello
I'm putting a 428cj into a 72 highboy that has a 360 and the np435 trans. Because the 428 is externally balanced I have to use the flywheel that came with it. The flywheel has a circle bolt pattern of 12-7/8 for the pressure plate. The flywheel on the 360 has a 12-3/8 circle bolt pattern. The short of it is, I need either an 11 or 11.5 clutch assembly for a 10 spline and 1-1/16 diameter input shaft with a pressure plate that has a 12-7/8 circle bolt pattern. The clutch companies I spoke with don't know how to address this when I ask for the pp circle diameter. I don't get it. Have any of you guys run into this? My other option is to drill the 428 pressure plate to 12-3/8 to fit the pressure plate that I all ready have. The machine shops I spoke with said I'd be better off getting the correct clutch and pp. Well if I could find one, I would.
I hope someone can help cuz man, is my head sore from hitting the wall.
Thanks
I'm putting a 428cj into a 72 highboy that has a 360 and the np435 trans. Because the 428 is externally balanced I have to use the flywheel that came with it. The flywheel has a circle bolt pattern of 12-7/8 for the pressure plate. The flywheel on the 360 has a 12-3/8 circle bolt pattern. The short of it is, I need either an 11 or 11.5 clutch assembly for a 10 spline and 1-1/16 diameter input shaft with a pressure plate that has a 12-7/8 circle bolt pattern. The clutch companies I spoke with don't know how to address this when I ask for the pp circle diameter. I don't get it. Have any of you guys run into this? My other option is to drill the 428 pressure plate to 12-3/8 to fit the pressure plate that I all ready have. The machine shops I spoke with said I'd be better off getting the correct clutch and pp. Well if I could find one, I would.
I hope someone can help cuz man, is my head sore from hitting the wall.
Thanks
Super Moderator
Joined: Apr 2004
Posts: 34,475
Likes: 2,800
Just use the 11" disc from the 360.
See post 5.
https://www.ford-trucks.com/forums/1...-diameter.html
The 11" disc will work fine in a PP made for 11 1/2".
Not sure why this is a mystery to anyone selling clutches for FE motors. They are probably trying to go by application, not dimensions.
Another way is to simply spec a 390 pickup clutch and double check the spline count, which you probably ought to do anyway.
See post 5.
https://www.ford-trucks.com/forums/1...-diameter.html
The 11" disc will work fine in a PP made for 11 1/2".
Not sure why this is a mystery to anyone selling clutches for FE motors. They are probably trying to go by application, not dimensions.
Another way is to simply spec a 390 pickup clutch and double check the spline count, which you probably ought to do anyway.
Thread Starter
|
Freshman User
Joined: Feb 2018
Posts: 49
Likes: 1
Thank you very much 85e150. I think the confusion was that I was asking for a 11.5 in. clutch. Looks like those are very rare today. However, I did not know the 390 flywheel has the circle I'm after. And with that being said, again there is also Thank you to NumberDummy for all the wonderful information he takes the time to post.
Thread Starter
|
Freshman User
Joined: Feb 2018
Posts: 49
Likes: 1
Yes, it is a 1970 cj. It has the C6AE-6380B flywheel with the cast in weight. However, I have absolutely no idea what it came out of. The block had the backwards "C" scratched into it and the webs were cast with the reinforcements.
Thread
Thread Starter
Forum
Replies
Last Post
1977F250Custom4x4
FE & FT Big Block V8 (332, 352, 360, 390, 406, 410, 427, 428)
3
Apr 3, 2013 07:13 PM
Hardlucktrucker
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
12
Oct 8, 2011 10:32 AM
ford390gashog
Pre-Power Stroke Diesel (7.3L IDI & 6.9L)
4
Aug 10, 2011 01:56 AM
yellow truck
FE & FT Big Block V8 (332, 352, 360, 390, 406, 410, 427, 428)
3
Aug 31, 2009 09:50 PM
wiley0ne
Clutch, Transmission, Differential, Axle & Transfer Case
3
Nov 22, 2002 06:42 PM
