Cam question
Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
Reduced base circle cams have been used from the beginning of hot rodding. In the beginning by grinding down a stock cam the effective lift (& duration) could be increased by basically keeping the high point of the cam & reducing the base circle.
By reducing the base circle clearance can be gained for example between a large cam & the rod bolts on a 383-400.
By reducing the base circle clearance can be gained for example between a large cam & the rod bolts on a 383-400.
Le Mans Master
Joined: Sep 2000
Posts: 5,635
Likes: 4
From: Orlando Floriduh
The lobe lift is the amountof lift from the base to the high point of the lobe. If you regrind a cam and you take material off of the high side the you must also take an equal amount off of the base to maintain the proper lift. That would make the base circle smaller than a stock cam but with the same lift. Only engines with adjustable valve trains can use that type of cam. Doing that does alter the geometry of the valve train somewhat. It is a common practice at cheapie engine/head remanufacturer's to use reground cams
Thread Starter
Burning Brakes
Joined: Jul 2000
Posts: 1,045
Likes: 3
So the problem I am having is that I am reto fitting newer roller cam into a earlier block. You need to do some slight grinding in the cam valley for clearance of the lifter retainers( the figure 8 things that keep the lifter from rotating). When I trial fit the roller lifter in to the bore it sits up about 3/8 of a inch. I am using the stock 79 cam, so the problem should go away when I install the correct cam?
