Bad LT4
Thread Starter
Pro
Joined: Apr 2018
Posts: 557
Likes: 105
Next question is the pistons. I think the LT4 piston is a little different than the LT1. The machine shop says they have them. I just want to make sure I get the right ones. I have searched online for replacements and the results are endless but never really specify lt4 application. Any help on this would be great. Stock part # or a link. Cast is fine not building a race motor.
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
Grand Sport Registry has a breakdown of the difference between LT1 and LT4 including part numbers. Some numbers will be discontinued. If you go with original engine it really won't matter since it will need.overbored. Trying to match OEM piston's weight would help with balancing. If you go with a better virgin block you may just need 2 oem pistons.
Melting Slicks
Joined: Dec 2004
Posts: 2,656
Likes: 635
From: Dallas TX
You aint using a stock piston if you are boring the block .060...
Usually "stock" replacement pistons can be had in .005 increments, but only like +- .020.
i know when we build jeep motors we order something like Part # and the suffix is A, B, C, D, E, F etc... pistons and you have to look at the book to see what size that is.
Usually "stock" replacement pistons can be had in .005 increments, but only like +- .020.
i know when we build jeep motors we order something like Part # and the suffix is A, B, C, D, E, F etc... pistons and you have to look at the book to see what size that is.
Last edited by rjacobs; Apr 18, 2020 at 08:34 PM.
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Well I think your gonna have to use an LT1 piston if you want hypereutectic like it came with. Which should reduce the compression increase that will come from boring and maybe decking the motor. LT1 pistons has a little deeper valve pockets and thats it. Stock LT1 replacements from Silv-O-lite is part #1489HC in 20, 30, 40, 60 thou overbore. Mahle has part #224-3498 in 20, 30, 40 thou overbore. NAPA has some Sealed Power replacements #SEP WH597CP20 but only in 20 thou overbore.
Best value I think is the Silv-O-Lite.
BTW the Grand Sport registry gives a part #12551526 for the LT4 piston but that number leads to nowhere.
Best value I think is the Silv-O-Lite.
BTW the Grand Sport registry gives a part #12551526 for the LT4 piston but that number leads to nowhere.
Advanced
Joined: Apr 2020
Posts: 81
Likes: 5
Advanced
Joined: Apr 2020
Posts: 81
Likes: 5
Well I think your gonna have to use an LT1 piston if you want hypereutectic like it came with. Which should reduce the compression increase that will come from boring and maybe decking the motor. LT1 pistons has a little deeper valve pockets and thats it. Stock LT1 replacements from Silv-O-lite is part #1489HC in 20, 30, 40, 60 thou overbore. Mahle has part #224-3498 in 20, 30, 40 thou overbore. NAPA has some Sealed Power replacements #SEP WH597CP20 but only in 20 thou overbore.
Best value I think is the Silv-O-Lite.
BTW the Grand Sport registry gives a part #12551526 for the LT4 piston but that number leads to nowhere.
Best value I think is the Silv-O-Lite.
BTW the Grand Sport registry gives a part #12551526 for the LT4 piston but that number leads to nowhere.
