You could certainly do that with your gear drive. My friend Wes uses a few of those Milodon gear drives in his big Ford engines. None of them came with any real instructions so we just figured it out what setting was needed to get the intake centerline that we wanted.

If you're planning on moving the cam around and experimented where you install the cam initially doesn't matter much as long as you know where it is. When I degree in a cam I always write on the gear what the ICL is and what was used to get it. It might say something like 0=106 or r4=106. That way when somebody has it apart in the future they'll know where the cam was when it was built. It is also a good idea to see how far you can move one way or the other before you start to run out of valve to piston clearance. Sometimes when you advance the cam the intake valve clearance can close up fast at about 10 degrees ATDC. I built a 400 Chevy for a customer last year and he bought all kinds of fancy stuff including a Jesel belt drive. When I was building the engine I made sure to check the clearance between the rod and the cam with it all the way advanced and all the way retarded just to know that it would clear. Then I did the same thing with the head installed and then I marked the drive with max safe advance and retard numbers. It could go forward about 4 and retard about 8 so they have plenty of room to mess around with the cam timing.

Earlier this spring I did an engine for a circle track customer where it had to make 15 inches of vacuum at 1000 rpm with a flat tappet hydraulic. I built the engine with my belt drive, experimented with a couple of cams and moved them around on the dyno, found what worked best and then put it together using a timing chain. It seems like it's very competitive at the track and it was probably worth the effort. I think I found about 15 horsepower with that and on an engine that only makes about 370 that's quite a bit.

 

Okay so I replaced the T Chain gear set today.using a Cloyes double roller which came with three keyways for indexing cam
Listed as -4• 0 +4°. The stock gear appeared to be very retarded almost half a tooth on the 18 tooth link style chain which would have had it close to 8-10 degrees retarded. Dave's cam profiles suggested that Ford ground in 7.3 degrees of advance into the stock cam in that vintage engine. Using the -4° setting of the new gear set resulted in the ignition timing moving from 8°BTDC to right around 12°BTDC it would therefore be proof that Cloyes uses crank° as reference. Also cam is most likely still retarded just not as bad as Ford's previous combination. Engine flashed up within 2 seconds of cranking idled very smooth exhaust note a tadd deeper. Throttle responded to blips snappy. Yet to check manifold vacum but I have no reference pre cam swap anyway. I didn't run it very long because no water pump installed yet and I want to drain the engine oil as a debris flush from the sump and refill. Thinking the 10- 15 seconds or so it ran was not enough to scavenge what would be flushing from snout area of oil pan to pan. I was careful with blocking crankcase debris during gasket removal. The beast breathes again. A perfect low budget power tweek and a refresh for mileage and power. Pretty sure we won't get 75MPG or be able to squeal the duallies out back of the 26 foot chassis but I bet the hills just got flatter and the pipes won't be as sooty. Big block rumble is a sweet sound.

 

That's good to know that the Cloyes set uses crank degrees. It'll be interesting to read how it runs once you have it going again.

 

Just returned from a local lake trip on the weekend since timing chain refresh. No real hard data during operation other than observation. Engine runs smooth, pulls strong in the river hills. Logged 173 miles and used 18.2 imperial gallons. That's only 9.5 miles per imperial gallon. Not great but reasonable for a 35 year old 26 foot barge. Dash fuel guage appears to be inaccurate as once full it registers 1/4" past full on display. Curious where real world MT is. Will do a pump out test eventually rather than run out on road. It appears to be a very large single tank version of chassis. No hint of preignition at all. Gas is stale from last year and half sitting in storage of previous owner. Static ignition timing set at 12°BTDC Running a 160° thermostat, regular 87 octane fuel. Cold air adapter piping is in place but secondary air cleaner opening defaulted to open on air cleaner housing as well. I believe it was to open on low manifold vacumm of 4 bbl operation only. Holley 750 Jetted 72 primary 80 secondary with a brown spring on secondary. Silly I did not check power valve rating but I had no online manifold pressure guage either. I think in need to use a tadd lighter spring. Going to be adding a manifold vacumm guage to dash display. Had a brief issue with hot fuel after mid operation extended idle in 30°C weather. Self retified once rolling again. Going to be adding cool fuel line plumbing, (run fuel line close to AC return line in insulated sleeve). Stock exhaust manifolds with minor porting job. Has true 2.5 inch dual exhaust thru Flow pro mufflers. They are a tadd restrictive but compared to the Thrush welded two chamber should be a bit mellow. I could not even hear them in the captains chair rolling down the road. Next lake run gets the Thrush for sound comparision tests. It needs a power steering cooler as oil got a bit hot, and perhaps an external transmission cooler as well. Overall it's a neat old rig with lots of life left to live. Saskatchewan has literally thousands of lakes to visit. Thanks to all who contributed information during the repair process.

Now on to the onboard generator and storage battery modifications, relocation of secondary battery larger wiring run to accommodate the 3G 130 amp alternator and diode isolation block feeding a 3000 watt invertor for early morning provincial park no generator silent toast and coffee option. 4D storage battery and regulated Power supply in place of old convertor tech. I love modifying things for application usage

 

I don't think that 9.5 mpg sounds too bad for a first time out. The vacuum gauge might be very helpful with mileage if you use it to try to keep it out of the power mixture a little more but that might not be possible on an RV. I wonder what it weighs?

 

I was going to slip into the local scales and record the weight once they are closed for the day just in case they get curious.. Definately need a online vacumm guage and check see what power valve is installed presently. Maiden voyage showed a few areas of concern that can be tweaked. Tuning a Holley is like foreplay ya gotta take is easy for best results.. lol