Home » Public Forums » GMCnet » Looking for a Set of Good Cylinder Heads
| Looking for a Set of Good Cylinder Heads [message #360042] |
Tue, 10 November 2020 09:38  |
TR 1
Messages: 348
Registered: August 2015
Location: DFW
Karma: -7
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Senior Member |
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Hi everyone,
So I recently burned a valve in my motor due to a piece of dried JB Weld wedging in between the valve and the seat as mentioned in an earlier thread. Unfortunately, the machine shop that has my heads has a large backlog related to COVID, and it does not look like they are going to be able to get my heads back in time for some travel we have planned over the Thanksgiving holiday. If anyone might have a spare set of rebuilt heads, or a known good set of used heads available, I would be very interested. Closer to Dallas, TX the better, but if someone would be willing to ship, I would be interested in that too. Am willing to buy outright, or possibly a trade for my heads once they are fully rebuilt...
Would also appreciate any input or leads on a source for a head that is available ASAP.
Thanks
Mark
Mark S. '73 Painted Desert,
Manny 1 Ton Front End,
Howell Injection,
Leigh Harrison 4bag and Rear Brakes,
Fort Worth, TX
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| Re: Looking for a Set of Good Cylinder Heads [message #360092 is a reply to message #360042] |
Thu, 12 November 2020 17:24  |
TR 1
Messages: 348
Registered: August 2015
Location: DFW
Karma: -7
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Senior Member |
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So I found a guy selling a used set of "G" heads on fleabay... Only thing is he said he had a broken head bolt and when he repaired it, he went ahead and changed to a set of Edelbrocks...
https://www.ebay.com/itm/114464891526?ViewItem=&item=114464891526
I was thinking about going ahead with these to get me on the road, but now that I've thought about it more, I'm concerned when the guy ran it with a broken head bolt it could have warped the heads.... I'm guessing that rusty spot near that outboard headbolt in the pics is due to coolant leaking out and pooling there?
What do you all think? Bad idea cause they could be warped? Or am I being paranoid?
Also, does anyone know are the "G" heads any better or worse than the stock "Js"? I believe these are small valve, same as the "Js"....
Mark S. '73 Painted Desert,
Manny 1 Ton Front End,
Howell Injection,
Leigh Harrison 4bag and Rear Brakes,
Fort Worth, TX
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| Re: [GMCnet] Looking for a Set of Good Cylinder Heads [message #360093 is a reply to message #360092] |
Thu, 12 November 2020 17:47 |
powwerjon
Messages: 849
Registered: March 2013
Karma: -2
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Senior Member |
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Looking at the pictures the manifold is not useable as it is a standard rise and not the low profile. If you get the entire package you could sell the manifold to some olds junky.
JR Wright
> On Nov 12, 2020, at 6:24 PM, Mark Sawyer via Gmclist wrote:
>
> So I found a guy selling a used set of "G" heads on fleabay... Only thing is he said he had a broken head bolt and when he repaired it, he went ahead
> and changed to a set of Edelbrocks...
>
> https://www.ebay.com/itm/114464891526?ViewItem=&item=114464891526
>
> I was thinking about going ahead with these to get me on the road, but now that I've thought about it more, I'm concerned when the guy ran it with a
> broken head bolt it could have warped the heads.... I'm guessing that rusty spot near that outboard headbolt in the pics is due to coolant leaking
> out and pooling there?
>
> What do you all think? Bad idea cause they could be warped? Or am I being paranoid?
>
> Also, does anyone know are the "G" heads any better or worse than the stock "Js"? I believe these are small valve, same as the "Js"....
>
>
> --
> Mark S. '73 Painted Desert,
> Manny 1 Ton Front End,
> Howell Injection,
> Leigh Harrison 4bag and Rear Brakes,
> Fort Worth, TX
>
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> GMCnet mailing list
> Unsubscribe or Change List Options:
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| Re: [GMCnet] Looking for a Set of Good Cylinder Heads [message #360094 is a reply to message #360092] |
Thu, 12 November 2020 17:43 |
powwerjon
Messages: 849
Registered: March 2013
Karma: -2
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Senior Member |
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You pays your money and you take your chances. G head is a generic 455 use and suppose to have big valves in usual application and they are 80 CC. You will need to check them over and they may need some machine work to make them usage.
J.R. Wright
GMC Great Laker MHC
GMCGL Tech Editor
GMC Eastern States Charter Member
GMCMI
78 GMC Buskirk 29.5’ Stretch
75 GMC Avion (Under Reconstruction)
Michigan
> On Nov 12, 2020, at 6:24 PM, Mark Sawyer via Gmclist wrote:
>
> So I found a guy selling a used set of "G" heads on fleabay... Only thing is he said he had a broken head bolt and when he repaired it, he went ahead
> and changed to a set of Edelbrocks...
>
> https://www.ebay.com/itm/114464891526?ViewItem=&item=114464891526
>
> I was thinking about going ahead with these to get me on the road, but now that I've thought about it more, I'm concerned when the guy ran it with a
> broken head bolt it could have warped the heads.... I'm guessing that rusty spot near that outboard headbolt in the pics is due to coolant leaking
> out and pooling there?
>
> What do you all think? Bad idea cause they could be warped? Or am I being paranoid?
>
> Also, does anyone know are the "G" heads any better or worse than the stock "Js"? I believe these are small valve, same as the "Js"....
>
>
> --
> Mark S. '73 Painted Desert,
> Manny 1 Ton Front End,
> Howell Injection,
> Leigh Harrison 4bag and Rear Brakes,
> Fort Worth, TX
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
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| Re: [GMCnet] Looking for a Set of Good Cylinder Heads [message #360100 is a reply to message #360096] |
Thu, 12 November 2020 19:35 |
TR 1
Messages: 348
Registered: August 2015
Location: DFW
Karma: -7
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Senior Member |
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Matt Colie wrote on Thu, 12 November 2020 18:51Most notable about the G heads that I have on a scrap engine (the block is junk) is that they only have rotors on the exhaust valves. They are also not complete.
Matt
Would not having rotators on the intake valves be worth swapping out the retainers for my existing J heads?
Mark S. '73 Painted Desert,
Manny 1 Ton Front End,
Howell Injection,
Leigh Harrison 4bag and Rear Brakes,
Fort Worth, TX
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| Re: [GMCnet] Looking for a Set of Good Cylinder Heads [message #360103 is a reply to message #360100] |
Thu, 12 November 2020 21:38 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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TR 1 wrote on Thu, 12 November 2020 20:35Matt Colie wrote on Thu, 12 November 2020 18:51Most notable about the G heads that I have on a scrap engine (the block is junk) is that they only have rotors on the exhaust valves. They are also not complete.
Matt
Would not having rotators on the intake valves be worth swapping out the retainers for my existing J heads?
Mark,
Obviously they could run without them, but they are there for a reason. As nearly as I know, there is no reason you could not. What I do not know without doing a lot of work is if the spring pockets in the head had to be cut deeper to keep the spring height the same. Unfortunately, I am very time restricted these days. If you can't do better, I will see what I can do. I know that shipping from Michigan will be a consideration.
Good Luck
Matt Colie
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: [GMCnet] Looking for a Set of Good Cylinder Heads [message #360118 is a reply to message #360108] |
Sat, 14 November 2020 15:16 |
TR 1
Messages: 348
Registered: August 2015
Location: DFW
Karma: -7
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Senior Member |
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Billy Massey wrote on Fri, 13 November 2020 09:24Hi Mark
I emailed you a few days ago about a set of ready to go heads in
Weatherford. I don't understand why you didn't reply. You could've been
up and running by now.
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Billy, that was my fault... I forget the forum is a mirror of the email list, and while I was monitoring the forum, I had not checked my email for a few days... I finally did see your email (and ones from several other people looking to help) last night. I assume you meant the heads Boyd Mooney had... I actually got in touch with Boyd based on your email and one he sent as well and purchased the heads from him this morning.... Working on getting them installed now.
Thanks to you both and to all the others who reached out to me looking to help. Again, this proves to me the best part about owning a GMC is the community behind it!
For those that are interested, the heads Boyd had were Ka castings, with a set of Comp Cams chromoly (Magnum) roller tip rockers. From my research so far, I need to pick up a set of .150" longer chromoly pushrods (Apparently, they say to use chromoly pushrods since the rockers/pushrods are located using guide plates) which are available from Comp Cams part # 7841-16.
The rockers themselves are part # 1442-16 or 1442-KIT which includes the guide plates and pushrods as a kit. I was concerned about running roller rockers as they are not really needed on a low rpm motor, and I've heard they are not as reliable as regular rockers.... However. from looking on the internet, this setup looks to be pretty reliable and the same rockers are used on kits for AMC and early Ford Windsor motors, so I'm going to give them a shot.
Also kind of curious to see if I notice a difference with the roller rockers and the big valve Ka heads vs my old Js.... The J heads I had were stock except for stainless exhaust valves. The rest of the motor is set up with higher compression pistons (runs well on mid-grade, but pings on regular) a mild RV cam, Howell fuel injection and headers, which I think will work well with these heads. If all goes well, I'll respond back here with impressions when I get back from our trip. We are (again, with luck) supposed to head down to Big Bend for Thanksgiving towing our 4cylinder Wrangler. Should be a good test of the new heads, with some hills and altitude (near sea level here, to 4500 in Alpine) thrown in for the trip.
Thanks again to everyone who offered to help... Especially Billy and Boyd who hooked me up with a set of heads locally!
Mark S. '73 Painted Desert,
Manny 1 Ton Front End,
Howell Injection,
Leigh Harrison 4bag and Rear Brakes,
Fort Worth, TX
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