View Poll Results: Which would you choose
Voters: 8. You may not vote on this poll
706 or 799 for LY5?
#1
Teching In
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Join Date: Nov 2008
Location: Texas
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706 or 799 for LY5?
I am putting together a LY5 to swap into my dads 84 C10 and I’m not sure which heads to use. When I got the motor some one had taken the original heads but I do have a set of 706 and 799s that I could use. I don’t know they history of either set so whichever ones I use will get a trip the the machine shop. I just looking for suggestions on which heads to use. Motor is stock bottom end LY5 with 222/232 .550/.550 112 lsa cam, .052 head gaskets, gen4 truck manifold, long tubes, 3200 stall, 4l60e, 3.73 gears. Best gas I can get around here is 91 octane. Street driven toy, not a race car and not used for towing
Option 1: stock 706 heads = 10.3:1
Option 2: stock 799 heads = 9.9:1
Option 3: milled 799 heads
Option 4: CNC ported & milled 799
local machine shop recommend using the 799 and not milling them because that would be stock and would work just fine (true), they also quoted me $750 to do a clean up mill and vale job (sounds high to me). For $150 more I could take them to Texas speed and have them CNC’d but would I notice any difference on a 5.3?
Option 1: stock 706 heads = 10.3:1
Option 2: stock 799 heads = 9.9:1
Option 3: milled 799 heads
Option 4: CNC ported & milled 799
local machine shop recommend using the 799 and not milling them because that would be stock and would work just fine (true), they also quoted me $750 to do a clean up mill and vale job (sounds high to me). For $150 more I could take them to Texas speed and have them CNC’d but would I notice any difference on a 5.3?
#2
TECH Veteran
$750 I think is probably the going rate. I would consider a mill and cnc job though for the $150 more
#3
TECH Fanatic
I’d run the 799’s and have them milled and valve job. That would make it more snappy down low.
#4
TECH Veteran
Who tf is seriously choosing 706 heads???
#6
TECH Veteran
Awesome, HP that is barely felt seat of the pants.
$300 core charge huh?
$300 core charge huh?
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#8
TECH Veteran
Have you ever used car-part? These are auto recyclers so they pull everything u-pick up.
Marketplace sucks *****.
Marketplace sucks *****.
#9
TECH Veteran
Here is Florida just for you sweetie.
#10
makes children cry
iTrader: (5)
looks like you ran a compression ratio calculator... cool, but did you check dynamic compression differences between the stock LY5 cam / 799s and your cam + whatever heads? that looks like a relatively healthy bump stick with a converter to match, so the SCR gain of 706s might get you back closer to factory DCR, and a port & valve job would open them up enough to flow nice good for a N/A truck.