camshaft base circle diameter

[1973gtx]

I need the camshaft base circle diameter of a stock cam, 1970 340 engine.
Tks Dave

 

[Cranky]

Don't know what the blue print specs are supposed to be but the cam I have varies with the average being 1.244". Are you trying to figure what the lift is?

 

[1973gtx]

Yes. the cam I removed had 1.85 base circle and 1.485 on .in &.ex lobes. looks like a Blue Racer CD 206.3 cam.pushrods were 7.500".total lift .450.. I got a extra cam with the engine,suppose to be stock. Base circle 1.310,.in 1.595, .ex 1.592. pushrods 7.500" total lift around .427, very close to stock.With .125" difference in base circles I'm wondering if I had any preload on the lifters with the cam I removed. I did not have it running, but it was in a Drag Car when removed ?????

 

[73rr]

1.85 sounds pretty big... Instead of worrying about the pre-load, or lack there of, why not just install adjustable rockers or adjustable pushrods?
With adjustment available you get to make the preload exact on each lifter.

...shameless plug....we sell adjustable pushrods for virtually any engine with prices starting at only $160 ppd.

I would not assemble any engine with hydraulic lifters without some adjustment available.

 

[1973gtx]

Sorry, the cam I removed was 1.185 base circle diameter, not 1.85. I'm leaning toward Comp Cam CL20-223-3.with 7.50 pushrods. bored .40 over,10.5 pistons. J heads, 2.02/ 1.60 valves.Looking for just a little bit more than stock.