All Small Six '63 170 vs. '65 200 cam

This relates to all small sixes
F

frozenrabbit

Well-known member
In piecing together bits and parts, I swapped the cam and lifters out of a piston seized '65 200 into a '63 170. 170 cam and lifters were pretty worn, 200 cam and lifters were in really good shape. Took care to keep lifters in order, new cam bearings, and will do a standard break in even though the cam and lifters are already mated.
I can't find exact specs, but the 200 cam definitely has more lift than the 170 from a quick caliper check, but didn't note the exact lobe difference. Haven't fired it up yet. Also had the 65 200 head redone with 1.5" and 1.75" valves, but it is small log.

Anyone know the actual difference in 170 to 200 cam specs? Any place I've looked at new stock cams says they are the same, but they are not. I doubt the locked up 200 junk yard engine was cammed.
Thanks.

I've got a complete, running when pulled 200 out of a 70 maverick that's going to get a full rebuild. The 170 is a low buck runner test bed.
 
Last edited:
Hi frozenrabbit, yes there is some difference between the 170 Six Hyd. Camshaft and the ones used in the 200 Six.
The specs for a 170 Hyd. Cam are 240 degrees Duration with a lift of .348. Intake opens at 9 Degrees and closes at 51 Degrees Exhaust opens at 42 Degrees and closes at 18 degrees Valve overlap is 27 degrees.


There were two 200 six Hyd. Cams I don't remember what year the change over was made though, first one had the same lift as the 170 but its timing specs are very different.

The first 200 Hyd. Camshaft was used roughly form 1963 1/2 to 1968 or maybe even up to 1972 it was 252 / 256 degrees Duration with a lift of .348. Intake opens at 7 Degrees and closes at 65 Degrees Exhaust opens at 55 Degrees and closes at 21 degrees Valve overlap is 28 degrees.

The later 200 Hyd. Camshaft has much better specs yet having 256 degrees Duration and has considerably more lift at .372. Intake opens at 28 Degrees and closes at 48 Degrees Exhaust opens at 76 Degrees and closes at 0 degrees Valve overlap is 28 degrees. In any case either one should be a good improvement over a very worn 170 Cam, best of luck
​
 
Couldn't really find specs. Only place I found 'stock' cams was RockAuto (which I do not trust) that lists the same cam for 144, 170, and 200.

I'm thinking about a log-ectomy on the old 170 head and 6 motorcycle carbs sometime.
 
I don't know if any aftermarket parts sources would even make those older Original Cam grinds anymore I think they maybe only pick one of a group. That sounds like a fun project did you find those motorcycle Carbs already? I also wanted to try and do a cut off Log Head to try and make my own version of the Australian 2V Head out of a small Log maybe some day will get to. I did just get some parts this last week to start building Large Log Tri Power Head that will be a bit different setup then has been done before. Best of Luck
 
Yes those Mikuni made Carbs are really nice I ran a 2V on my 77 Datsun L20B engine back in the 1980's after using the Webers it was a good bit more powerful for my combo. I will be going with the Redline Webers on the Large Log Head though.
 
Have you seen the guy on Youtube, running a lawn mower carb on a 302 in a Maverick? ThunderHead289. He's using an O2 sensor, I think an arduino micro controller, and some GM control valve for a controlled vacuum leak to get a working fuel ratio because the mower carb only has about a 1" bore, and could never flow enough air. Impressive results.

That would be an interesting set-up, but the 6x controller set up would be a nightmare. I doubt a 1"bore carb would be enough for each cylinder.
 
Yes I actually did see that some time back he's certainly a smart guy to be able to make it work as good as it did. It probably wouldn't be all that bad at 1 inch for each cylinder. The old Offy Tri Power Intake kits used a 1 inch hole for the end carbs I think it would of worked so much better at 1 1/2 to 1 3/4 inch or maybe more which is what I am planning to do and really will be looking into it.
 
When I built my tri-power with homemade adapters and linkage. I started out with the small Holley 1-7/16" bore carb and made the hole closer to 2 and 5 so I could get 1-7/16" hole in the head. I thought it was more important than "even spacing". I think that is why it was a little faster than others. Later changed to 1-11/16" bore YFs, and just tapered the adapter, no more material to go 1-11/16" at the picked location. Went 3 tenth's faster with the YFs. Was a 4-speed top loader, 3.80 8"rear end gear and drove well, not sure if it would drive well with a low stall auto.
Had I started out with the 1-11/16" carb I would have moved the adapter so I could get 1-11/16" hole in the head or as close to it as I could. The Offy was made for the masses and not full power in mind.
 
Hi drag-200stang, thank you for that tip on your Tri Power setup those are very good ideas. That is along the lines of what I have been thinking about for awhile now that those end Carbs and their position to the front and rear Cylinders should be able to flow so much better and since the end cylinders are usually the leanest running too. Do you happen to have any pictures of your old set up or any of its measurements. I will be using the larger Log Head and also making up all the Carb mounting flanges so will be a clean slate approach to the old Bill Strope and Associates, Eldenbrock, & Holmen Moody, and the newer Offy Tri Power set ups. LOL, maybe its true that great minds think alike. As a side note the car an early Mustang will also have have a 4-speed top loader with an 8"rear end and had started thinking last night about what would be a suitable gear ratio maybe in the 3.55 to 3.80 range.
 
Sorry Bubba, I have no good way to do pics at this time. I copied the tri power from Hot rod mag pics, the Edelbrock style I think, made them out of steel, that may be why with gasket material, aviation Permatex I was able to seal with only .090" surface area in a couple spots and four bolt mounting. With casting being a little different not sure what I have would help and if I knew that I was going to run the 1-11/16" carbs I would have shifted over more. Just lay out closer to 2 than 1 for a bigger bore and closer to 5 than 6. I made the flat spots on the log carefully with a file.
The 3.80 was great around town but x way driving as I remember it, was 3000 rpm at 60, a five speed would have been nice.
 
You must log in or register to reply here.
Back
Top