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Lance mentioned "rev kit" in the red spring thread so I got to typing, and put it here.
Here's a refresher on what a rev kit is: Something marketed by performance v twins/al hodge. Stronger pushrods (briggs uses aluminum on one of the pushrods), valve spring retainers, spring shims for the stock springs, and a thinned flywheel key to advance ignition timing. The "rev kit" was designed for one of the vanguard class racers that doesn't allow aftermarket valve springs. It's fine for a stock cam, although pricey, as it minimizes spring pressure on the stock rocker arms and will still keep the valves from floating with a stock cam, like from 4 to 5 grand.
However, if you put a real cam in it, the rev kit is worthless, as the stock springs are not enough near 5 grand and beyond. You may not run over 5 on purpose, but it happens
and it's important to set the exhaust valve down gently on it's seat since it's red hot.
You don't need the billet trinket al hodge pushrods when steel vanguard pushrods for a couple $ will run 8,000 rpm and never fail. George at E.C. Distributing will set you up with double springs and retainers for far less $.
Rutledge, running near 5 grand is getting up there for stock rods, not much of a cushion. Your hard cranking may be too much clearance on the exhaust valve lash, as it would degate the function of the steel ball sticking out of the heel of the cam lobe to hold the valve open during cranking. Did you move the piston down the bore a 1/4" past TDC when setting lash? If you don't, you'll be setting lash on that ball, = no compression release.
If that doesn't work, take the starter apart and clean the grooves between the commutator segments and put brushes in it if they're worn crooked. Lube the bushings, too. My starter wouldn't crank mine hot, (cam w/no compression release, long rods), but after going through the starter again and setting lash to .005 ( I had been running more clearance for torque) it has been starting well. Also, the duration of an aftermarket cam will give you a little "compression release" effect. The only real cure for a "never have to think about it again" is a different flywheel w/ring gear and a real starter for $250 ish.
A couple of my friends with frontiers are having sluggish cranking on their 23's. They sound like weak starters/batteries, etc. George says the #1 cause of hard cranking in the vanguards is excessive valve lash. Have to keep in mind the "easy spin" briggs starting is built around an undersized, low amp starter, meant to be cranked by any half charged lawn and garden battery, depending on the exhaust valve being held off it's seat at below cranking rpm by the compression release. The compression release is a work of art, however, very neat design. There is a spring on it that can fail, causing the comp release to not work. It's not common to fail on vanguards, but is on some other briggs engines.
I would also think twice about not using the long rods. A cam will take some static compression ratio away. If you drove my 18 I think it'd convince you. It is long rod/shaved piston and thick gasket. You can boost pump gas with a lead additive, just carry a quart of it with you instead of hauling AV gas around. You'll never make any power at 8 to 1 compression without going to a bigger engine or forced induction. Well, that's my opinion, not fact.
Run the idea by George. To get carried away here, you could do the long rod/shaved piston/flat top, and put 23 hp heads on it with bigger chambers to lower the compression. Then you'd need a different intake manifold.. which would come with a 2 barrel George prefers to go the other way, put smaller chamber 16 hp heads on the 18/20 blocks. With a thin gasket and shave the head about .040 
He says compression makes torque, and he likes to build the vanguard for torque, rather than rpm. The 23 heads would be an rpm engine with it's ports, but there's no way to get the compression back up.
Here's a refresher on what a rev kit is: Something marketed by performance v twins/al hodge. Stronger pushrods (briggs uses aluminum on one of the pushrods), valve spring retainers, spring shims for the stock springs, and a thinned flywheel key to advance ignition timing. The "rev kit" was designed for one of the vanguard class racers that doesn't allow aftermarket valve springs. It's fine for a stock cam, although pricey, as it minimizes spring pressure on the stock rocker arms and will still keep the valves from floating with a stock cam, like from 4 to 5 grand.
However, if you put a real cam in it, the rev kit is worthless, as the stock springs are not enough near 5 grand and beyond. You may not run over 5 on purpose, but it happens
and it's important to set the exhaust valve down gently on it's seat since it's red hot. You don't need the billet trinket al hodge pushrods when steel vanguard pushrods for a couple $ will run 8,000 rpm and never fail. George at E.C. Distributing will set you up with double springs and retainers for far less $.
Rutledge, running near 5 grand is getting up there for stock rods, not much of a cushion. Your hard cranking may be too much clearance on the exhaust valve lash, as it would degate the function of the steel ball sticking out of the heel of the cam lobe to hold the valve open during cranking. Did you move the piston down the bore a 1/4" past TDC when setting lash? If you don't, you'll be setting lash on that ball, = no compression release.
If that doesn't work, take the starter apart and clean the grooves between the commutator segments and put brushes in it if they're worn crooked. Lube the bushings, too. My starter wouldn't crank mine hot, (cam w/no compression release, long rods), but after going through the starter again and setting lash to .005 ( I had been running more clearance for torque) it has been starting well. Also, the duration of an aftermarket cam will give you a little "compression release" effect. The only real cure for a "never have to think about it again" is a different flywheel w/ring gear and a real starter for $250 ish.
A couple of my friends with frontiers are having sluggish cranking on their 23's. They sound like weak starters/batteries, etc. George says the #1 cause of hard cranking in the vanguards is excessive valve lash. Have to keep in mind the "easy spin" briggs starting is built around an undersized, low amp starter, meant to be cranked by any half charged lawn and garden battery, depending on the exhaust valve being held off it's seat at below cranking rpm by the compression release. The compression release is a work of art, however, very neat design. There is a spring on it that can fail, causing the comp release to not work. It's not common to fail on vanguards, but is on some other briggs engines.
I would also think twice about not using the long rods. A cam will take some static compression ratio away. If you drove my 18 I think it'd convince you. It is long rod/shaved piston and thick gasket. You can boost pump gas with a lead additive, just carry a quart of it with you instead of hauling AV gas around. You'll never make any power at 8 to 1 compression without going to a bigger engine or forced induction. Well, that's my opinion, not fact.
Run the idea by George. To get carried away here, you could do the long rod/shaved piston/flat top, and put 23 hp heads on it with bigger chambers to lower the compression. Then you'd need a different intake manifold.. which would come with a 2 barrel George prefers to go the other way, put smaller chamber 16 hp heads on the 18/20 blocks. With a thin gasket and shave the head about .040 He says compression makes torque, and he likes to build the vanguard for torque, rather than rpm. The 23 heads would be an rpm engine with it's ports, but there's no way to get the compression back up.
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