73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: dumbucket1 on October 15, 2009, 12:58:09 pm
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Mortec doesn't have it listed. Can any one tell me if casting 346238 are peanut port heads. Thanks
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Yes they are.
346238 = 1975-87 454 Open 113.0cc
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Ok I saw them on craigslist and didn't know if they were worth fooling with.
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Yes they are.
346238 = 1975-87 454 Open 113.0cc
just because they are o-port doesnt mean they are peanut head..
chevymainia.. doesnt list as peanutt port heads..
i got a set of peanut o-por heads... and regular O-port heads
i can snap a picture tomorrow if that helps
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I have been building BBCs for 20+ years, and have never heard of a "peanut port".
What is a peanut port?
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I have been building BBCs for 20+ years, and have never heard of a "peanut port".
What is a peanut port?
peanut is o-port is ~25% smaller then a std o-port.. rough 200-220cc vs the 250-260cc intake runners..
both run 2.06/1.77 vlvs
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All cylinder heads that were on Truck motors from 75 forward ARE peanut port heads, so I can pretty much say that they ARE peanut port heads.
This is a comparison of the 2:
(http://www.captkaoscustoms.com/images/ovalvspeanut.jpg)
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10-4 on the peanut ports.
Capt, what is the casting # on the cylinder head in the left of the photo?
I have the 353049 casting heads on my 454. These puppies are nasty. Adding 2.19/1.88s helped them breathe slightly better, but the ports needed worked a little to take full advantage of the bigger valves.
If building a street engine, or a 4x4 off road engine, there isn't a head that is much better than the 353049 (1973), or the 336781 (1974) castings. I guess these are the true oval ports.
I would recommend the 2.19/1.88s, with the pocket porting, and intake gasket match, and hang on. :o
One other little mod is to polish the combustion chambers. That is good for a couple of ponies as well.
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The ovals are 049's, they ARE oval ports.
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10-4 on the peanut ports.
Capt, what is the casting # on the cylinder head in the left of the photo?
I have the 353049 casting heads on my 454. These puppies are nasty. Adding 2.19/1.88s helped them breathe slightly better, but the ports needed worked a little to take full advantage of the bigger valves.
If building a street engine, or a 4x4 off road engine, there isn't a head that is much better than the 353049 (1973), or the 336781 (1974) castings. I guess these are the true oval ports.
I would recommend the 2.19/1.88s, with the pocket porting, and intake gasket match, and hang on. :o
One other little mod is to polish the combustion chambers. That is good for a couple of ponies as well.
i got a 781 casting head with 2.06/1.75 valves. i havent CC then intake or exhuast runners yet. i did flow bench them on a SF-600 @ 28inHg
intake flow rates
.100 72cfm
.150 80cfm
.200 99
.300 130
.400 246
.500 253
.550 257
exhaust flow
.100 73
.150 97
.200 115
.300 146
.400 163
.500 179
.550 182
short turn is pretty rough to say the best.. 2.19/1.88 would be very nice.... i might do that and new guides as well...
im currently getting a short block back inspecs.. mains, bore, deck balanced.. still up between a 3cc FT or a -12cc dome piston from KB.
in comparison.. world casting O-port heads http://www.worldcastings.com/products/merlin-oval-port-iron-heads.html flow this @.800"
316 intake, 290 exhaust (Super Flow 600)
All heads flowed with a standard .750" intake plate, without exhaust tube, and 28" of water.
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Do any of you guys know anything about the 343772 head?
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AFAIK 343772 are peanut Port heads. Great for low end power, crappy for anything else.
The good Oval Port heads are 781s or 049s I honestly wouldn't put money in any other factory oval port BBC head.
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in comparison.. world casting O-port heads http://www.worldcastings.com/products/merlin-oval-port-iron-heads.html flow this @.800"
316 intake, 290 exhaust (Super Flow 600)
All heads flowed with a standard .750" intake plate, without exhaust tube, and 28" of water.
heres then flwo numbers ate a more respect lift.. compared to 253/179 @.500.. with a 2.06/1.77 10% difference
with a 2.3/1.88 valves
@ .500 - Intake 277, Exhaust 227
@ .600 - Intake 285, Exhaust 249
Regards,
Scott Nelson
Engineer
World Products
(631) 981-1918 x137
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I have 781's with 2.25/1.88 pocket ported and they work great. there are alot of BB out there making around 600HP with these heads 049's too!(port work of course)
I found some stuff from this guy racer1320 good readin
http://www.chevelles.com/forums/showthread.php?t=23714&highlight=468+combo
http://www.chevelles.com/forums/showthread.php?t=57753
More stuff
http://users.erols.com/srweiss/tablehdc.htm#Chevy_Big_Block
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Some good info here. I used to have a set of 781 castings, dont remember what I ever did with them though.
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got my 781 bench flow after some pocket portting in the vlv bowl these are still with 2.06" valve.. i havent touched the actual runner yet.. 290-300cfm would be possible out of the 2.06" vlv....
lift-ported- stock
.100 114-72
.150 136-80
.200 163-99
.300 228-130
.400 254-246
.500 275-253
.550 278-257
.600 283
the exhaust.. the actually valve is smaller then the bowl.. i pick up 2-6cfm over the previouse stock flow numbers... 1.88 would be a big help here...