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Chev 350 overhaul

Posted: Thu Oct 25, 2007 5:57 pm
by fud2468
Thanks to Al, especially:
We got the old crank out with no trouble. I estimate the worst rod bearing had about .030" clearance. At the machine shop we were told the general wear was so bad that we needed a new crank, and that the rods needed reconditioning, which we went for.
Machinist said cam gear and chain were OK, and we kept the old oil pump since it had shown good pressure when cold.
New crank, rings & all bearings, seals, gaskets & labor came to $380 which we felt was reasonable, and it runs well now.
On the Ford Truck Enthusiasts site there's been discussion in the past about getting better economy on FE (360, 390) engines. A smaller carb, as small as 390CFM has been tried with good success, provides better mix at low speeds with sacrifice of power at higher RPM's, and I wonder if this approach would as well work for a Chev.
Ray Mac.

Posted: Thu Oct 25, 2007 6:43 pm
by asavage
The spreadbore Q-jet is already pretty efficient at small throttle openings; in my youth it was rumoured that (depending upon loading) replacing a 2V intake with a 4V intake & Q-jet could improve economy. Makes sense, but I never saw "real" numbers, so it might be a myth.

I don't know as I'd go as small as a 390 cfm on a 350 or larger, but that's your call. I don't commute in my truck: when I want a truck, I need a truck, and I don't care how much fuel it uses.

Smaller carb

Posted: Fri Oct 26, 2007 8:32 am
by fud2468
Yeah, the trick is to stay out of the secondaries.
As for me, if I keep this truck it will be for hauling mostly on level 2-lane roads where conditions won't permit going over 60 anyway.
Though I have a '92 Ranger 2.3 that will give me twice the gas mileage, I figure the Chev. will haul more than twice as much, so I'm ahead there on economy as well as time.
Gas here is now $3.03 for 87 octane.
Ray Mac.

Posted: Fri Oct 26, 2007 9:43 am
by asavage
In my neck of the woods:

Petrodiesel = $3.67
Biodiesel B99 = $3.75