All Small Six Back in the Saddle
- Thread starter cr_bobcat
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This relates to all small sixes
On a 300 six the front of the camshaft's front bearing journal is even with the front of the block.
Since your engine uses a thrust plate the front of the camshaft should also be flush with the front of the block
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The cam lobes are definitely offset.
Please measure the first two lifter bore locations.
Install a stock lifter in the first lifter bore and measure from the side of the lifter to the front of the block.
What is that measurement?
Next install the stock lifter in the second lifter bore and measure from the side of the lifter to the front of the engine block.
What is that measurement?
Add 1/2 the lifter diameter to those two measurements to get the lifter bore center locations from the front of the block.
Install a stock lifter in the first lifter bore and measure from the side of the lifter to the front of the block.
What is that measurement?
Next install the stock lifter in the second lifter bore and measure from the side of the lifter to the front of the engine block.
What is that measurement?
Add 1/2 the lifter diameter to those two measurements to get the lifter bore center locations from the front of the block.
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Next measure the first cam lobe location from the back side of the cam lobe to the front of the cam journal.
Then subtract 1/2 the width of the cam lobe to get the lobe center location from the front of the cam.
Then measure the second cam lobe location from the back side of the second cam lobe to the front of the cam journal.
Then subtract 1/2 the width of that cam lobe to get the lobe center location from the front of the cam.
What measurements did you get?
The difference between lifter bore centers and the cam lobe centers from the front of the block will be the roller cam lobe offset needed to make roller cams.
The roller cam lobes for the 240/300 roller cams had to be repositioned .095" back from the flat tappet cam lobe locations.
Then subtract 1/2 the width of the cam lobe to get the lobe center location from the front of the cam.
Then measure the second cam lobe location from the back side of the second cam lobe to the front of the cam journal.
Then subtract 1/2 the width of that cam lobe to get the lobe center location from the front of the cam.
What measurements did you get?
The difference between lifter bore centers and the cam lobe centers from the front of the block will be the roller cam lobe offset needed to make roller cams.
The roller cam lobes for the 240/300 roller cams had to be repositioned .095" back from the flat tappet cam lobe locations.
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I'll take a look this week. Was at a Cub Scout campout this past weekend.
No pressure on this but, any more head way?
Not yet. Monday I had to drive my kid to soccer practice 1.5 hr away and last night we had Cub Scout meetings. Kids and their schedules have been a major damper on my progress. I was able to get a bunch done the previous weeks because I had to work from home a number of days. I'm hoping to get out there tonight while my daughter is at dance. Fingers crossed.....
Your children are an investment of infinite value. Relatively- "stuff", including classic cars/engines, is nothing. (When old enough, they can be incorporated into assisting with the mechanic work. Accomplishes quality time, and they learn a valuable skill while you get your projects done. Win-win. 
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I took some measurements last night. I didn't like my numbers as it didn't seem consistent. I'm going to re-do it when I get home from work. I think I must've bumped the caliper when trying to take a picture or something. That said, I think the offset you quoted for the 300 is going to be pretty similar to what the 200/250 will be. Which makes sense - they both use 0.875" hydro lifters. If the lifters have to spin by using an offset, it's likely the same offset... But anyway, will know tonight.
Thanks for doing all of the leg work on this. I am following eagerly. I wasn't intending on pulling my camshaft any time soon but... you never know. If this can be fitted in a 200 then it will definitely go on my todo list.
Hey, slightly off topic for just a moment... I see from your signature you are running a similar setup on your 200 to what I will have once I install the C9 head with the bigger valves. I see you're running HEI with 20° initial advance on manifold vacuum. I'm running 24° initial on manifold with an HEI (I might pull mine back just a touch). Do you recall what springs are you using on your mechanical advance? I'm using silver on mine currently and if I drop my initial timing, I'll probably go with the lighter gold springs.
I did measure the offset of 3 lobes on a 200 and 250, and they where not what was expected. So I think I made an error, be nice to see what you come up with.
Yes, See post #85 and 86 above.
See post # 85 and 86 above.
Please use that same procedure.
Ignore this if you are already doing so.
