Engine questions

FSJ Jackson

I just got a remanned 401 from Performance Automotive Warehouse and I have some questions. First, I need to buy a flywheel and I don't know which one to get. PAW says the rotating assy was "computer balanced" but I don't see how they can balance it without the harmonic balancer or flywheel. Should I just get a neutral balanced balancer and flywheel, or what? Second, I ordered the crane cams 3/8 roller rockers, what rocker stud can/should I use. From what I can figure I need to have the rocker bolt holes drilled and tapped for the 3/8 studs. I have the 502 casting heads with 5/16" rocker bolt holes. Thanks in advance for any advice. I wouldn't want to get anything wrong, that would most likely be very costly.

tufcj

You're probably not going to want to hear this, but you'll have to remove the heads and have some machine work done to convert to screw in studs for the roller rockers. This is if it has the factory "bridged" type rockers. You will need to have the pedestals milled down slightly, and add guide plates to keep the rockers and pushrods straight (that's what the bridges do now). I used pre 1974 heads on my Jeep (these had factory screw in studs and built in guides). I had to use +.100 pushrods and ARP # 134-7104 studs with Crane gold roller rockers. The base of most screw in rocker studs is 7/16". I wouldn't do ANY drilling/tapping with the head on the engine. No matter how careful you are, some chips will get into the engine, and could cause havoc. Bob. tufcj

FSJ Jackson

Thanks, that's what I thought.

Gremlin4ever

tufcj wrote
I used pre 1974 heads on my Jeep (these had factory screw in studs and built in guides).

Bob.
tufcj

THis has been "illing" me for awhile and you've answered it for me, thanx :lo1l:

I have been trying to get away from aftermarket guides. My heads have raised portions between the two center exhaust valves which causes me to alter the guides. The factory guides always seemed to break and the rocker tip would slip off the valve head onto the retainer "ouch!" I've seen many sets of heads with the oval pushrod hole thinking they were like Fords in being built in guides. Thanx again for the info! :t:

tufcj

For those of you with the later bridged rockers, Harland Sharp makes a set of roller rockers that bolt on and do not need guide plates. The intake and exhaust are pinned together so they cant twist. P/N is SV4004, you can see a pic here:

http://www.harlandsharp.com/bolton3.htm

Page down to AMC and click on the part # for a pic. They are pricey, but probably cheaper than pulling the heads and associated millwork.

Bob.
tufcj