HEI question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

BluTrukker · 12-15-2009, 04:30 PM

I have 2 used HEI's that I can to upgrade my truck. I am not all that familiar with them, and need some advice. They are both out of mid 80's trucks. One is off a big block and one off a small block. I haven't closely inspected either one yet, they are laying on a shelf at my buddies place and he told me I can have whatever one I want. One has a vacuum advance and one doesn't. Whats the deal with that? I thought all the older stuff had vacuum advance? Is there a benefit to using one over the other? I am putting it on a 307, so I'm only looking for reliable cruising not power.

68gmsee · 12-15-2009, 04:57 PM

I'd get the one with the vacuum advance. If you're not familiar with the HEI there is tons of stuff on the net to help you. Also, educate yourself on what the mechanical and vacuum advance does and how it's adjusted.

Here's a good site that you can look at but there are others just as good or better: http://rmcavoy.freeshell.org/HEI.html

71meangreenc10 · 12-15-2009, 05:05 PM

Replace the vacuum advance with one that is an adjustable VA, makes a big difference.

Smitty

12-15-2009, 04:30 PM	#1
BluTrukker BOHICA Join Date: Mar 2008 Location: Stewartville, MN Posts: 440	HEI question I have 2 used HEI's that I can to upgrade my truck. I am not all that familiar with them, and need some advice. They are both out of mid 80's trucks. One is off a big block and one off a small block. I haven't closely inspected either one yet, they are laying on a shelf at my buddies place and he told me I can have whatever one I want. One has a vacuum advance and one doesn't. Whats the deal with that? I thought all the older stuff had vacuum advance? Is there a benefit to using one over the other? I am putting it on a 307, so I'm only looking for reliable cruising not power. __________________ Trying to save someone from their own stupidity is like teaching a pig to dance. It is a waste of your time, and it annoys the pig! Last edited by BluTrukker; 12-15-2009 at 04:31 PM.

12-15-2009, 04:57 PM	#2
68gmsee Active Member Join Date: Jul 2007 Location: Centrally located between Houston, Austin and Waco. BCS area. Posts: 7,947	Re: HEI question I'd get the one with the vacuum advance. If you're not familiar with the HEI there is tons of stuff on the net to help you. Also, educate yourself on what the mechanical and vacuum advance does and how it's adjusted. Here's a good site that you can look at but there are others just as good or better: http://rmcavoy.freeshell.org/HEI.html

12-15-2009, 05:05 PM	#3
71meangreenc10 Its a Truck Thing...... Join Date: Dec 2004 Location: Sierra Vista, Arizona Posts: 3,179	Re: HEI question Replace the vacuum advance with one that is an adjustable VA, makes a big difference. Smitty __________________ 71 C10 283/3SPD Full Resto 71 GMC 1500 Sierra Grande http://67-72chevytrucks.com/vboard/s...d.php?t=518599 70 C10 Suburban Former military GSA truck. 72 Chevy Blazer 4X4, Sloppy Jo, Mountain Climber. Wife says no more trucks. http://67-72chevytrucks.com/vboard/s...d.php?t=707378 72 GMC 1 Ton Motor Home, wife said no more trucks until she saw this one. Gen 3 6.0/4L80E 4.10 http://67-72chevytrucks.com/vboard/s...d.php?t=761110 68 GMC Suburban was 3/4 ton, now 1/2.Wife shook her head 71 C30 Wrecker 71 C20 Scott-Bilt As weird as it gets..BB Cheyenne AC Truck 68 GMC Long Stepside. They keep following me home 69 C30 Former Motor Home, Flat Bed time 70 G20 Red-E-Kamp Conversion "I'm your Boogy Van"



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