Posted by Brian in Oregon on August 21, 2000 at 22:12:32:
In Reply to: ID'ing 318 posted by Ken in CO on August 21, 2000 at 16:53:02:
Ray Quiring of Helitool is doing the 318/NP420 conversion kit.
He has a prototype kit done and shown on his website. I'm due to get the 2nd protoype any day now.
I don't know how to tell the exact year of a 318 (yet).
You want a later model 318, something from the early to mid 1970's would work. As you face the front of the engine, the lower water outlet will point to your left (passenger side).
I assume you know that there was an early 318 built on the old Hemi blocks. It is easily identified by having two bolts through the middle of each valve cover. The 318 you want will have five bolts AROUND the lip of the valve cover.
It is important that you make sure the crank is drilled for a throwout bearing. Most early 70's 318's were drilled, but as time went on and most wound up in automatic cars, the chances of getting a drilled crank declines.
You will need a 318 flywheel and bellhousing. Ray has a casting number shown on his site for the bellhousing and says to use that casting number. My bellhousing is identical, but has a different casting number ("3497270-ND" over "CWC" over "2"), so evidently there at least two bellhousings which will work, and possibly more. You want a mechanical bellhousing, not a hydraulic. You also don't need mounting ears if you are using Ray's kit. Don't be tempted to use an aluminum bellhousing. There are some identical to teh iron. Ray has a concern that the unsupported transmission might snap the bellhousing in a severe drop. I agree, best to err on the side of caution. You don't want the transmission to fall on the trail in front of your buddies.
As far as pulleys, try and get them already on the engine. Mine were off, and it is a bitch trying to piece them back together again.
Don't worry about the motor mount ears. Some blocks have 4 ears per side, some have 3 and a few have 2. Ray's kit accomodates all three types.
I guess a lot of 318's were made with steel cranks. I have no clue how to tell the difference. I don't know which is in my engine. You really don't need to worry either way, since you are doubling the HP and torque anyway. Any more and you are going to start experiencing failure of original parts in the drivetrain if you get moderately abusive.
Exhaust manifolds. Most 318's have a center dump on the passenger side, and a rear dump on the drivers side. You want center dump manifolds for both sides if you are using Ray's kit. I am taking out the heat control and welding the holes up (actually only to one - someone welded one up long ago. You might be able to find a couple already welded up.)