After three weeks of asking for the cam to be checked out (measured), and knowing the shop owner favored replacing the cam, I picked it up, took it home and broke out the digital Verneer Caliper. This was reportedly a stock cam which ran nice in a '66 401 that I drove. Heres what I measured: [TABLE="width: 503"] <colgroup><col span="4"><col><col></colgroup><tbody>[TR] [TD]Position[/TD] [TD]Round[/TD] [TD]Lobe[/TD] [TD]Lift[/TD] [TD]Spec[/TD] [TD]Re-[/TD] [/TR] [TR] [TD]Bearing[/TD] [TD="align: right"]1.6645[/TD] [TD][/TD] [TD][/TD] [TD]1.665 - 1.666[/TD] [TD]Measured[/TD] [/TR] [TR] [TD]Dist Gear[/TD] [TD][/TD] [TD][/TD] [TD][/TD] [TD][/TD] [TD][/TD] [/TR] [TR] [TD="align: right"]1[/TD] [TD="align: right"]1.0805[/TD] [TD="align: right"]1.349[/TD] [TD="align: right"]0.2685[/TD] [TD][/TD] [TD]x[/TD] [/TR] [TR] [TD="align: right"]2[/TD] [TD="align: right"]1.0805[/TD] [TD="align: right"]1.348[/TD] [TD="align: right"]0.2675[/TD] [TD][/TD] [TD]x[/TD] [/TR] [TR] [TD="align: right"]3[/TD] [TD="align: right"]1.08[/TD] [TD="align: right"]1.3325[/TD] [TD="align: right"]0.2525[/TD] [TD][/TD] [TD]x[/TD] [/TR] [TR] [TD="align: right"]4[/TD] [TD="align: right"]1.0805[/TD] [TD="align: right"]1.3475[/TD] [TD="align: right"]0.2670[/TD] [TD][/TD] [TD]x[/TD] [/TR] [TR] [TD]Bearing[/TD] [TD="align: right"]1.6945[/TD] [TD][/TD] [TD][/TD] [TD]1.695 - 1.696[/TD] [TD][/TD] [/TR] [TR] [TD="align: right"]5[/TD] [TD="align: right"]1.0795[/TD] [TD="align: right"]1.3445[/TD] [TD="align: right"]0.2650[/TD] [TD][/TD] [TD][/TD] [/TR] [TR] [TD="align: right"]6[/TD] [TD="align: right"]1.0805[/TD] [TD="align: right"]1.347[/TD] [TD="align: right"]0.2665[/TD] [TD][/TD] [TD][/TD] [/TR] [TR] [TD="align: right"]7[/TD] [TD="align: right"]1.0795[/TD] [TD="align: right"]1.346[/TD] [TD="align: right"]0.2665[/TD] [TD][/TD] [TD][/TD] [/TR] [TR] [TD="align: right"]8[/TD] [TD="align: right"]1.08[/TD] [TD="align: right"]1.347[/TD] [TD="align: right"]0.2670[/TD] [TD][/TD] [TD][/TD] [/TR] [TR] [TD]Bearing[/TD] [TD="align: right"]1.7245[/TD] [TD][/TD] [TD][/TD] [TD]1.725 - 1.726[/TD] [TD][/TD] [/TR] [TR] [TD="align: right"]9[/TD] [TD="align: right"]1.0805[/TD] [TD="align: right"]1.345[/TD] [TD="align: right"]0.2645[/TD] [TD][/TD] [TD]x[/TD] [/TR] [TR] [TD="align: right"]1[/TD] [TD="align: right"]1.0805[/TD] [TD="align: right"]1.3465[/TD] [TD="align: right"]0.2660[/TD] [TD][/TD] [TD][/TD] [/TR] [TR] [TD="align: right"]11[/TD] [TD="align: right"]1.0805[/TD] [TD="align: right"]1.346[/TD] [TD="align: right"]0.2655[/TD] [TD][/TD] [TD][/TD] [/TR] [TR] [TD="align: right"]12[/TD] [TD="align: right"]1.0805[/TD] [TD="align: right"]1.346[/TD] [TD="align: right"]0.2655[/TD] [TD][/TD] [TD]x[/TD] [/TR] [TR] [TD]Bearing[/TD] [TD="align: right"]1.7545[/TD] [TD][/TD] [TD][/TD] [TD]1.755 - 1.756[/TD] [TD][/TD] [/TR] [TR] [TD="align: right"]13[/TD] [TD="align: right"]1.081[/TD] [TD="align: right"]1.3465[/TD] [TD="align: right"]0.2655[/TD] [TD][/TD] [TD]x[/TD] [/TR] [TR] [TD="align: right"]14[/TD] [TD="align: right"]1.0805[/TD] [TD="align: right"]1.347[/TD] [TD="align: right"]0.2665[/TD] [TD][/TD] [TD]x[/TD] [/TR] [TR] [TD="align: right"]15[/TD] [TD="align: right"]1.0805[/TD] [TD="align: right"]1.3475[/TD] [TD="align: right"]0.2670[/TD] [TD][/TD] [TD][/TD] [/TR] [TR] [TD="align: right"]16[/TD] [TD="align: right"]1.081[/TD] [TD="align: right"]1.3465[/TD] [TD="align: right"]0.2655[/TD] [TD][/TD] [TD][/TD] [/TR] [TR] [TD]Bearing[/TD] [TD="align: right"]1.7845[/TD] [TD][/TD] [TD][/TD] [TD]1.785 - 1.786[/TD] [TD] [/TD] [/TR] </tbody>[/TABLE] From what I can find online, the intake and exhaust lobes should both be giving '.0269" of lift. And these numbers are less than that. So, am I interpretting this correctly that this cam should be replaced? If I replace this stock cam, in my non-race car, is there a subtle improvement that should be figured into the new cam like more lift, duration, or seperation? Or stick to stock like the NAPA #229-1606 replacement? Thanx in advance for the info!
Looks like your 3rd lobe is worn. Replace. Even if it wasn't worn, my opinion would be to use the tighter lc cam anyways (109* vs. 114*) . Can't comment on Napa cam w/o specs. There is much to search on this forum regarding Nailhead cams. I'm definitely not a Nail expert but I build very aggressive combos, and then make them daily driver friendly. I don't expect you to go that far, but this is from my perspective... In general, factory cams leave a LOT on the table, even if it's a non-racecar. I find significant improvements in throttle response as well as mileage. Being that you have to replace the cam, why wouldn't you use something that will improve the vehicle overall, being that the cost is similar? That being said, one gift of the Nailhead seems to be starting with a pretty decent (for factory) cam. Referring to the tighter lc cam here. If you stay close to a stock powerband, slightly more aggressive specs help an engine in many ways (think factory roller). Most roughness can even be tuned out. Minor valve bowl work (and good valve job) tones down a cam, and widens the powerband, especially on the bottom end. To me, these minor things are nearly free... Of course, I'll leave specific Nailhead rec's to the board.
If your already rebuilding it, you might as well replace the cam. I wouldn't order a stock replacement from an auto parts store. Most are actually milder than stock. If stock is what your after, get the smallest cam TA Performance offers.
Re: '66 401 Rebuild - NAPA CAM Info from old post Here is the info I read on that NAPA/Clevite cam from Telriv's old post...... We are talking about the NAPA # 229-1606 right?? which is the only one made for the NailHeads from '57-'66 made by Clevite. The specs are as follows. Cam lobe lift-.269" I&E Gross lift at 1.6 ratio =.430" (more than likely closer to .406") Overlap-74* Advertised duration-295*I-302*E SAE duration 284*I&E Duration @.050"=207*I&E Intake lobe centerline-112* Exhaust " " -116* The following is measured @.050" for timing: Intake opens-9*ATC-closes-36*ABC Exhaust " -39*BBC- " -12*BTC Maybe you should try to retard it 4 degrees as the factory did for more top-end. I have installed a couple of these at my shop & the cars I put them in appeared to perform pretty well. I did degree them in & installed both of them 4* retarded as the factory did. I also know that they fall flat on their face at about 4800 RPM's. Tom T Need to buy a cam and lifters pretty quick here, going to ask Russ' advice also. If anybody wants to chime in, Please do!
Buy Russ's cam if you are looking for a fast decision. You'll want something slightly more aggressive than the NAPA. It will still behave nicely. Mucho info by searching the board...
