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Old 05-14-2017, 11:46 PM   #13
Nima
Blue 67
 
Join Date: Apr 2004
Location: Western WA
Posts: 1,169
Re: Updating a LM7 for transplant

Quote:
Originally Posted by BossHogg69 View Post
First thing I'd do is pull the valve covers and make sure it doesn't have Castech heads on it before spending a bunch of money on go fast parts.

https://www.jalopyjournal.com/forum/...ngines.933574/

http://speedtalk.com/forum/viewtopic.php?f=1&t=28519

http://www.gminsidenews.com/forums/f...r-heads-83436/

WELL documented problem and usually only shows up after 100k miles or so. My '05 GMC 5.3 started giving me issues after about 140k, smoking, using antifreeze with no visible leaks, then started running hot and sludgy oil.

Anyway, I had previously installed a Comp Cams LSR 265 cam, long tube headers, Blackbear custom tune and a Yank 2600 stall converter - which really woke things up. After both of the heads cracked, I installed a set of Texas Speed PRC stage 2.5 heads to go along with the other stuff I already had and the thing came alive.
Thanks, I will check it out when the engine is delivered. Meanwhile I keep my fingers crossed! It is funny that you never know these things about cars until you buy them!
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1953 GMC 3/4 ton: current project
1967 C20: 5.3 voretc with T5 conversion, 4 wheel 8 lug disc brake
1972 Nova: my 4 door sport sedan! 5.3 voretc + T5 conversion. drivable project, FUN!!
1979 Camaro Z28: 5.3 vortec conversion with build TH350: drivable project, Fun to drive
1992 Camaro RS convertible (Z28 clone): 5.3 conversion with build T5: on going project
2005 Silverado 2500, 4x4 Duramax, original owner
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