Cam Base Circle Difference

[redrider2911]

So I'm getting ready to build my stroker and will be taking .050 off the block as well as running a CompCam 6-232-4. This got me looking into what pushrod length I would need to get proper lifter preload. I was originally going to go with the .050 shorter 4.2 pushrods based on my new deck height difference, but then got to thinking about the possible difference in base Circle diameter on the cams.

I took some quick measurements with my calipers and got a base circle diameter of ~1.435 on the 98 4.0 cam and ~1.375 on the 232 CompCam. I plan on using the stock lifters so this will definitely effect my final lifter preload. In fact, in theory my existing pushrods should work fine between the .050 milling of the block and .025 smaller cam base circle RADIUS.

I haven't seen this information anywhere else so I thought I would go ahead and post up. The only reason I could think as to why others haven't been effected by this is because most probably use the compcams lifters as well and if I had to guess they are probably .025 taller.

Thoughts?

[SilverXJ]

The only good way to judge preload is after the block and head is assembled.

When you say stock lifters, are you talking about new ones or your current stock lifters? If you are talking about new ones they are very over priced. I would go with Hylift/Johnson lifters. Probably save around $200 for a better lifter. If you are talking about using your current lifters, you do not want to put used lifters on a new cam.