would I get a better MPG with a 4.3 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

iluvmy72 · 04-03-2005, 06:52 PM

I have a 4.3 throttle body engine and 700r4 tranny form a 88 astro van. The van is in sad shape but the engine and tranny have been rebuilt. Would this be better for economy if used as a daily driver? The truck currently has a standard 350 engine in it with a 4 barrel carter carb.

CHEVIBUBBA · 04-03-2005, 07:57 PM

if your simply running empty to work & back etc. then, yes.
primarily due to e.f.i. & o.d.
the throttle body injection isn't that much better than a carb that is correctly tuned but, it is better.
i would expect about 5% better due to e.f.i., 7-10% better for v6 vs. v8 & 10-15% due to going overdrive.
if you start pulling or hauling your gonna miss the v8!& your mileage will likely be worse.

Longhorn Man · 04-03-2005, 08:03 PM

My observations with a 92 W code 4.3 (that's the Vortec injection) was pretty poor MPG even when the engine was still fairly tight. Had it in a 92 S-10 blazer with the 4l60 (e?) tranny, and I think the best I ever saw out od it was 21 MPG...in a small light weight body. It was OK performance wise, but like he said, put a trailer on it, and it is a total dog....heck, put 4 full sized men with duffle bags in it and it is a dog.

longhorn71 · 04-03-2005, 08:28 PM

i think the milage would be worse even empty.the older trucks are way heavier than the newer ones.So the engine would be workin harder to pull just the truck around.IMO i would swap the rear gears and or put an overdrive trans in it

LUV2XCLR8 · 04-03-2005, 08:32 PM

PERSONALLY, IN A DD BEATER TRUCK, I THINK A 4.3 IN A 67-72 WOULD BE

04-03-2005, 06:52 PM	#1
iluvmy72 Registered User Join Date: Jan 2002 Location: Springville, UT, USA Posts: 1,010	would I get a better MPG with a 4.3 I have a 4.3 throttle body engine and 700r4 tranny form a 88 astro van. The van is in sad shape but the engine and tranny have been rebuilt. Would this be better for economy if used as a daily driver? The truck currently has a standard 350 engine in it with a 4 barrel carter carb.

04-03-2005, 07:57 PM	#2
CHEVIBUBBA got boost? Join Date: Mar 2005 Posts: 123	if your simply running empty to work & back etc. then, yes. primarily due to e.f.i. & o.d. the throttle body injection isn't that much better than a carb that is correctly tuned but, it is better. i would expect about 5% better due to e.f.i., 7-10% better for v6 vs. v8 & 10-15% due to going overdrive. if you start pulling or hauling your gonna miss the v8!& your mileage will likely be worse. __________________ '70 chevy lwb w/'67 hood. 357 s.b.c. built, 4l60 w/vigilante lockup high stall converter, edelbrock pro-flo,brodix heads,comp cams rollerized w/ belt drive, one piece d-shaft, yada, yada, yada..... '82 honda v45 sabre"the black"

04-03-2005, 08:32 PM	#5
LUV2XCLR8 The LuvShack Garage Join Date: Jan 2004 Location: Maple Grove, TN (West Side) Posts: 30,482	PERSONALLY, IN A DD BEATER TRUCK, I THINK A 4.3 IN A 67-72 WOULD BE __________________ Owner/Op: "TN Classic Transport Carriers" The Toy: "Square Vette" 72 Hybrid Blazer Toy Barn: "LuvShack" 40 x 60 x 20 Shop Tow Piggy:"Maddy" 88 Silverado 3500 Hauler: "Feathers" 14 Aluma 8218T

04-03-2005, 08:03 PM	#3
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	My observations with a 92 W code 4.3 (that's the Vortec injection) was pretty poor MPG even when the engine was still fairly tight. Had it in a 92 S-10 blazer with the 4l60 (e?) tranny, and I think the best I ever saw out od it was 21 MPG...in a small light weight body. It was OK performance wise, but like he said, put a trailer on it, and it is a total dog....heck, put 4 full sized men with duffle bags in it and it is a dog.

04-03-2005, 08:28 PM	#4
longhorn71 Senior Member Join Date: Sep 2004 Location: CANADA Posts: 1,681	i think the milage would be worse even empty.the older trucks are way heavier than the newer ones.So the engine would be workin harder to pull just the truck around.IMO i would swap the rear gears and or put an overdrive trans in it



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