What's with timing the 70s 350s???? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

TreverSlyFox · 01-12-2006, 11:01 PM

Figured it was time to do complete tune-ups on my 71 GMC 1 Ton and the 70 Chevy C-10, both are V-8 350s.

Didn't have a timing light so I crused down to NAPA and bought a Timing light that does more than timing, about $178 $$$ more. Anyway I'm looking over the GMC and I can't find the timing degree pointer, so I grab my trouble light and really start looking. IT'S UNDER THE WATER PUMP !!!!!!!!!!!!!!!

And I mean UNDER, just the "teeth" sticking out, can't see the degrees etched on it. Looked at the 70 C-10 and it's the same, no way to get a timing light on it without sticking your hand into the running fan. Now I'll admit I was a FORD man until lately and only got into the 70s Chevy trucks recently, but this has me stumped. I don't see any way to get a light on the pointer and even if I could I can't see the markings to set it. I must be missing something because it doesn't make any sense NOT to be able to time the engine.

The 71 GMC has HEI ignition with a 4 speed and the 70 C-10 is an automatic with points.

TYIA

TSF

carl609 · 01-13-2006, 12:30 AM

if you paid that much for a timing light it should have an advance feature, then all you need to know is where zero is on the pointer. if you have a long water pump you can usually point the light behind it and see the mark.

Russell · 01-13-2006, 12:48 AM

I usually just get on top of the core suppport, and look straight down behind the water pump. Should be fairly visible from there

If you rub that timing tab, you'll find the degrees etched into it. I've never seen one without.

jhow66 · 01-13-2006, 01:59 AM

You have late model engines. 70 & 71's had timing tabs at about the 2:00 to 3:00 oclock postion. Might want to check your engine #'s-could be 305's.

jimfulco · 01-13-2006, 04:22 AM

Later-model engines (mid-'70s) with the 12:00 timing marks came with long water pumps that you could shoot the light down behind. Yours got a short pump?

68C15 · 01-13-2006, 09:02 AM

they were designed that way for timing ease when there is all the extra stuff mounted on driver side of engine. if you want you can just get a different pointer & after using a TDC stop to find true TDC make a new mark on the balancer.

01-12-2006, 11:01 PM	#1
TreverSlyFox Registered User Join Date: Sep 2003 Location: Houston, Missouri Posts: 17	What's with timing the 70s 350s???? Figured it was time to do complete tune-ups on my 71 GMC 1 Ton and the 70 Chevy C-10, both are V-8 350s. Didn't have a timing light so I crused down to NAPA and bought a Timing light that does more than timing, about $178 $$$ more. Anyway I'm looking over the GMC and I can't find the timing degree pointer, so I grab my trouble light and really start looking. IT'S UNDER THE WATER PUMP !!!!!!!!!!!!!!! And I mean UNDER, just the "teeth" sticking out, can't see the degrees etched on it. Looked at the 70 C-10 and it's the same, no way to get a timing light on it without sticking your hand into the running fan. Now I'll admit I was a FORD man until lately and only got into the 70s Chevy trucks recently, but this has me stumped. I don't see any way to get a light on the pointer and even if I could I can't see the markings to set it. I must be missing something because it doesn't make any sense NOT to be able to time the engine. The 71 GMC has HEI ignition with a 4 speed and the 70 C-10 is an automatic with points. TYIA TSF

01-13-2006, 12:30 AM	#2
carl609 Registered User Join Date: Jan 2006 Location: Lynnwood, WA Posts: 63	Re: What's with timing the 70s 350s???? if you paid that much for a timing light it should have an advance feature, then all you need to know is where zero is on the pointer. if you have a long water pump you can usually point the light behind it and see the mark.

01-13-2006, 12:48 AM	#3
Russell Professional Grade Join Date: May 2003 Location: Fort McMurray, Alberta Posts: 7,915	Re: What's with timing the 70s 350s???? I usually just get on top of the core suppport, and look straight down behind the water pump. Should be fairly visible from there If you rub that timing tab, you'll find the degrees etched into it. I've never seen one without. __________________ 1995 Chevrolet 2 Door Tahoe (6.6L LBZ Duramax / ZF6 / NP241 with 1 ton solid axle swap)

01-13-2006, 01:59 AM	#4
jhow66 Registered User Join Date: Jun 2002 Location: Knoxville Tenn. Posts: 3,058	Re: What's with timing the 70s 350s???? You have late model engines. 70 & 71's had timing tabs at about the 2:00 to 3:00 oclock postion. Might want to check your engine #'s-could be 305's. __________________ 56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer

01-13-2006, 04:22 AM	#5
jimfulco Registered User Join Date: May 2003 Location: Shreveport LA Posts: 3,170	Re: What's with timing the 70s 350s???? Later-model engines (mid-'70s) with the 12:00 timing marks came with long water pumps that you could shoot the light down behind. Yours got a short pump?

01-13-2006, 09:02 AM	#6
68C15 blood type; Retumbo Join Date: Jan 2004 Location: next to my reloading bench Posts: 10,269	Re: What's with timing the 70s 350s???? they were designed that way for timing ease when there is all the extra stuff mounted on driver side of engine. if you want you can just get a different pointer & after using a TDC stop to find true TDC make a new mark on the balancer. Last edited by 68C15; 01-13-2006 at 09:02 AM.

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