73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: c10dude75 on August 19, 2015, 11:09:03 pm
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Yeah was just curious as to what kind of heads these are tried looking up pictures to see what they might be. I did find something similar but still wasn't it. If anyone knows feel free to comment thank you👌.
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There should be a number stamped into the inside of the head. You use the last three digits to decode the head.
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Alright ill have to check that out thanks man👍. But yeah I bought this truck about a month ago it looks like it was semi speedy at 1 point so trying to find out what kind of secrets it's hiding haha.
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kind of hard to see from the angle and grime on there
does this help?
(http://www.geocities.ws/meanracing/headmarks.JPG)
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Yeah seen the chart before that's why I was asking cus I didn't see it on there. Thank you for the help hopefully get to the bottom of this soon.
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could you get a better picture?
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That is the casting mark I boxed in red in Irish's post. It is reversed but that is it.
(http://images.tapatalk-cdn.com/15/08/21/1d64e7b27b8dba980a72ced7095af820.jpg)
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3927185....69-76...307/327/350..70cc chambers
or
3986339....71......307/350......74cc chambers
The 339 would be better than the 185 but once you get the numbers be easier to tell
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Yeah I was going to say looked like that L shaped 1 but wasn't sure since it was pointing the other way thought they might of been different but thank you for clearing that up. And alright ill have to look either later today or tomorrow to find out for sure the number.
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So I looked under the valve cover found this number looks like it says 186? But on that chart it be a different head and that's not possible cus looks nothing like that other head symbol. Also found out the gas is in the oil and when I bought it dude said it had a sticky lifter at full throttle which I comfirmed. But could it just be cus the oil is to thinned out and it's just not oiled properly?
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3927186....69-70...302/350......Camel hump,64cc chambers,accessory holes
An ok head but nothing that great. 64cc chambers are pretty small.
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gas in oil can be from a bad fuel pump diaphragm. if you let the truck sit for a couple days of so does it seam to take a couple more cranks than normal to start?
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Here is some more info for those heads.
http://www.crankshaftcoalition.com/wiki/SBC_cylinder_head_identification
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gas in oil can be from a bad fuel pump diaphragm. if you let the truck sit for a couple days of so does it seam to take a couple more cranks than normal to start?
Gas in oil can also be from a leaky carburetor
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Yeah got to pump the gas pedal 3 times then it starts. Kid I bought it from been doing that since he got it. also might have leaky carb cus there is what looks to be gas caught in the torker intake like might of been running down or flooded i don't know. And wouldn't 64cc create higher compression? And thanks for the link ill have to check that out. maybe ill take a pic up close of the carb so can see what's going on.
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Correct about the the chambers, lower the chamber size, higher the compression ratio. Thats because there's less area for all that air and fuel to be squeezed into.
Camel hump heads are from what I have heard, considered pretty great old school cast iron heads. But since it doesn't have the casting mark that is referred to as the "camel hump", I'de say it's uncurtain they are hump heads or 1 of the 2 that go with the tetris shape that you did find on them.
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Yeah usually hump heads or at least the 1s iv seen don't have accessory holes in the front so I don't think their humps. Got to be 1 of those L shaped 1s but the last 3 numbers matches the humps according to that chart unless it's missing numbers and stuff.
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double hump heads dont have accessory holes but they can be drilled for them
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There are double hump heads with the raised areas & bolt holes. They started in late '68 or '69 when the long waterpump setup came to be in the Camaro, ect.. The Vette's still used a short waterpump, but had bolt hole heads as well from what I've read.
To the OP, to me, it looks like you have the head that has been outlined in the Red Square. Definitely not the double hump heads. Over the years I've found MANY flaws in the published numbers vs. what a person has in their hand (example, Years ago in print was that all 010 blocks were 4 bolt main...maybe started out that way, however there were MANY 2 bolt 010 blocks. I've found similar situations with heads as well)
Lorne
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Very interesting. So I guess what would be a nice up grade from what I got? Also how much hp you guys think this turd 350sb might make? It's got a edelbrock torker intake and summit 4 barrel I think 600cfm and full length headers and Tetris heads now lol dunno what came it got or anything else just curious to know in a ball park of what it would have.
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186's are very decent heads. They are an upgrade of the old camel hump heads. You can make some good power if they are 2.02's with some port / bowl work done to them.
Small “camel hump” c/n 186, 492. Later high performance or “fuelie” heads, some c/n 186 (1969 and later) and all c/n 492 have accessory bolt holes. Either 1.94" x 1.50" or 2.02" x 1.60" valves, 64cc nominal chamber volume.
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What about a modern style head?for a decent price?
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Vortec heads in my opinon are much better than the heads of old, BUT they require a new intake.