Sooo many questions

"I bought a 1979 Viking 43&#39

"I bought a 1979 Viking 43' - 3 years ago. It has 2 350 crusaders (454's) that "seem" to run okay. I have replaced a piston on my #2 cylinder on the starboard engine, rebuilt the carbs , replaced a few exhaust parts, a starter, rebuilt a raw water pump and have done routine maintenance.
Question 1. I have no idea how many hours are on the engines. If I wanted to put a meter in, where does it go?
Question 2. I have looked through the threads here about popping through the carbs and have gotten answers from fuel delivery to ignition timing. Someone told me the other day that one of the cam lobes is worn and is causung the problem. Any thoughts on that route?
Question 3. Timing. At what RPM should these engines be timed at?"

"off the ignition switch - met

"off the ignition switch - meter 'runs' when the key is 'on'.

if its an intake lobe, maybe. Not too hard to pop the cover and measure it (dial indicator required).

Base timing set at idle. Very good idea to verify that full advance of ignition timing occurs (should be at least 30 degrees by 3000 rpm)."

"And check your ignition wires

"And check your ignition wires. Old wires can crossfire under load, especially if the wires are separated properly.

Jeff"

"Could a wiped out exhaust lob

"Could a wiped out exhaust lobe also cause backfiring at higher RPMS? I can imagine residual pressure building up in the cylinder from incomplete discharge of the exhaust gases. To take an extreme case, if the exhaust valves don't open at all the pressure in the cylinder would be reflected back through the carb when the intake valve opens.

I lost a cam lobe (I thought it was an exhaust lobe but could be mistaken) and the affected engine backfired badly over 2000 RPMS. From what I have been told the 454's are famous for wiping out cam lobes. As Mako says you can easily measure cam lift and determine if there is a problem. I was lucky to have enough clearence in front to slide the cam out without pulling the motor. Make sure you get a marine grind cam if you go this route."

"to followup on major_tom'

"to followup on major_tom's post regarding the cams:

The marine cams are made by the same houses that grind the auto versions. When we rebuilt our big blocks, I ordered the 'factory parts' and was surprised to get "aftermarket parts". I paid more at 'dealer price' for the 'factory' parts than the going 'street price' for the same end item.

Best way to find the cause is to diagnose it. Get out the good old compression tester and vacuum gauge and see what the basic condition is. That's a whole lotta boat to be pushing, even for a pair of geared down big blocks."

"Cams; I've got hundreds

"Cams; I've got hundreds of hours on two aftermarket cams. Wolverine and Competition Cams; 0.27/.28" LOBE lift, 206 deg duration @.050.
About $132 each gear or chain driven."

"Wolverine cams! Hey, I ran o

"Wolverine cams! Hey, I ran one of them for years in my autocross car. Good deal.

Jeff"