Thread: another which cam question,

Tweet

were to start so many things.. and some are only bbc problems. ok i will try to help . roller cam is the only way to go on the bbc chevy there about four things why i use solid or hyd roller cams #1 there not many oils the can hold up to the flat lifter cams. i will call them flat just for this post but there not really flat there ground on a 50inch raidus Crown as this keeps lifter truning in bores and cam lobe is ground with a 0007 to 002 taper to help the lifter to turn . if they stop the cam lobe will start a flat spot and fail . #2 added valve spring lbs can added to wiping of cam lobes lower speed low oil splash and poor oil with no zddp .#3 as bbc do not have all lifter bores on the same plane it s really hard to know were every lobe to lifter bore is were it should be ,so with added spring Lbs this can add to faster wear if something is off . they are more whys to it. i would be happy to go over all this on the phone as i not much for posting fingers hurt to much . as for the roller walking /moving .yes as there is some crown on some roller lifters rollers. lifter has no way of holding the cam on track so can will walk with no stop . so with a roller cam you need a stop ..this can be done two ways buy a mark VI cam and chain set your block should have two 1/4 20 thread holes in front of the cam boss this has allways been there on all older bbc. all 454 are drilled and taped for a cam plate to hold cam ..BUT.. never was used with IV stock cam from 1965to89 .only on rev rotation engines had gear to gear timming and with out plate the cam would walk out this cam plate will not fit or work only on a marine cam for rev rotation . so with the new bbc VI has a cam hold down plate for the oem roller engings . so i done many older 396 /496 old IV blocks if you go this way you need the hold down plate for this can be had at the Gm dealer it is the mark 6 454 part it so happens to work on the older gm blocks . but you need the timming set and step nose cam for VI 454 .the other way is buy a button that fits in front of cam to front timming cover as stock cover can flex .i make up a stop on the back side of water pump to hold it from moving if you go cast alum timming cover there will be no need for a stop but will still need to fit a front thrust button to the front of cam . as for roller cams ..if your thinking of going this way. i used many that were 500/500 lift and 220/"220 and 110 intake center line and round 114 Lsa .there many cams over the years around this size. i used for mild street stuff . othere things come in to play you can run and to No piston to valve room very comon on bbc. intakes if heads have been reworked and bigger valves .your valve seals may not clear new springs and get crushed as some Gm heads have long valve guides need to get cut down . so i use a viton rigid steel chimney valve seal