The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - 1988 Canadian GMC C1500 305 TBI w/TH400HD going into 1973 C20 Custom Crew Cab

dwmitchell61 · 10-13-2015, 02:17 PM

Driveline has been dropped off at Six States Distributors driveline shop. Will have it back today, maybe tomorrow. Shorten 3".
My mechanic friend reshaped the shift rod from the 1988. It shifts marvelously! We found the distributor had been stabbed 180 degrees out by a PO. We re-stabbed it... It fired right up... But we still missed by a tooth. It was loping at idle and it seemed to have a leaking TBI gasket. I will buy the gaskets for the TBI & air cleaner and the spacer that has the crankcase ventilation air hose attached. When we change the gasket we will deal with the distributor being a tooth off.
Other than that, the engine runs smooth & sweet. No oil smoke or coolant steam in the exhaust. It has a barely visible "soot" when the throttle is "blipped".
The throttle linkage from the 1988 was too long, But I can swage on a new stop in the cable to "shorten" it.
The gear ratio options that were available for this truck seem to have been 4.10:1 & 4.56:1. I programmed the DRAC/VSS buffer for the 4:10 ratio and the 30" tire diameters she has on it.

10-13-2015, 02:17 PM	#17
dwmitchell61 Registered User Join Date: Jul 2015 Location: Benton City, WA Posts: 37	Re: 1988 Canadian GMC C1500 305 TBI w/TH400HD going into 1973 C20 Custom Crew Cab Driveline has been dropped off at Six States Distributors driveline shop. Will have it back today, maybe tomorrow. Shorten 3". My mechanic friend reshaped the shift rod from the 1988. It shifts marvelously! We found the distributor had been stabbed 180 degrees out by a PO. We re-stabbed it... It fired right up... But we still missed by a tooth. It was loping at idle and it seemed to have a leaking TBI gasket. I will buy the gaskets for the TBI & air cleaner and the spacer that has the crankcase ventilation air hose attached. When we change the gasket we will deal with the distributor being a tooth off. Other than that, the engine runs smooth & sweet. No oil smoke or coolant steam in the exhaust. It has a barely visible "soot" when the throttle is "blipped". The throttle linkage from the 1988 was too long, But I can swage on a new stop in the cable to "shorten" it. The gear ratio options that were available for this truck seem to have been 4.10:1 & 4.56:1. I programmed the DRAC/VSS buffer for the 4:10 ratio and the 30" tire diameters she has on it.