The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - PROJECT: How would a Chevrolet dealer build a shop truck in the early 1970s?

**mattfranklin** · 02-06-2019, 05:08 PM

Replaced the fuel tank sender (even though the old one looked new) and blew out the line with compressed air. Also, inspected carb bowl and float (looked clean and float moved freely) and replaced sintered brass inlet filters. It started on starter spray, but then kept running strongly a long time. I was able to confirm the initial timing (with vac disconnected) at ~12-14 deg +/- and adjust the idle mixture screws to best idle plus a quarter turn out (all 4 of them).

Now it still seems to be overheating. (Previously, during the break-in, it did not overheat during the high rpm, only when I tried to lower the speed toward idle.) Will replace cap and thermostat. If that doesn't do it I'll get a shroud for the fan. Does anyone know the quality differences between Classic Industries and LMC? I think the LMC one is about $60 and the other one is about twice that. Maybe I have that backwards.

Got a new proper GM dipstick with new upper and lower tubes to replace the old one with the bent upper tube. I realized why the old one was bent -- so it would fit with the shorty headers. Oh well. Now looking into stock/Corvette ram's horn options for exhaust manifolds so the proper dipstick will work. Looking at DD1's (Darien's) build and this link, too, for ram's horn manifold options: http://67-72chevytrucks.com/vboard/s...d.php?t=653906

02-06-2019, 05:08 PM	#90
mattfranklin Senior Member Join Date: Dec 2011 Location: Moraga, CA Posts: 804	Re: PROJECT: How would a Chevrolet dealer build a shop truck in the early 1970s? Replaced the fuel tank sender (even though the old one looked new) and blew out the line with compressed air. Also, inspected carb bowl and float (looked clean and float moved freely) and replaced sintered brass inlet filters. It started on starter spray, but then kept running strongly a long time. I was able to confirm the initial timing (with vac disconnected) at ~12-14 deg +/- and adjust the idle mixture screws to best idle plus a quarter turn out (all 4 of them). Now it still seems to be overheating. (Previously, during the break-in, it did not overheat during the high rpm, only when I tried to lower the speed toward idle.) Will replace cap and thermostat. If that doesn't do it I'll get a shroud for the fan. Does anyone know the quality differences between Classic Industries and LMC? I think the LMC one is about $60 and the other one is about twice that. Maybe I have that backwards. Got a new proper GM dipstick with new upper and lower tubes to replace the old one with the bent upper tube. I realized why the old one was bent -- so it would fit with the shorty headers. Oh well. Now looking into stock/Corvette ram's horn options for exhaust manifolds so the proper dipstick will work. Looking at DD1's (Darien's) build and this link, too, for ram's horn manifold options: http://67-72chevytrucks.com/vboard/s...d.php?t=653906 __________________ (Very) Slow-Going Build Thread: Stock 1970 Short Step with Stock 1970 LT-1 http://67-72chevytrucks.com/vboard/s...d.php?t=567340 Last edited by mattfranklin; 02-09-2019 at 04:27 PM.