I have a new LS1/LS6 block and I was informed that different year blocks had different length head bolts. Is there some truth to that? Anyone had experience with such a thing? Thanks.

 

Absolutely the truth. The length changed in early 2004. My build date is Dec 2003 so I have a 2003 LS1 block and it has both short and long bolts.

 

^^^he is right......

 

Yes sir. Pre '04 has long and short. '04 and after has the short "LS2 Style" bolts.

Jon

 

Thanks for the clarity, guys!
I always find more help here than any other place regarding my technical questions.

Is that the same for iron 6.0L blocks also?

 

I do know this, the older style is way more expensive in ARPs. I priced them when doing my build. Like $100 for the newer style and $200 for the older style.

 

I just was informed that the cam journal size was different as well from 2003 and earlier vs. 2004 and later years...

 

The camshaft is the same, it uses different cam bearings. A 99 cam will fit a 04 block if that's your concern.

 

^^^oh, ok...thank you for the info.

 

why is that?

 

^^^I'm assuming that they are more expensive just because ARP wants them to be...lol...or they want everyone to invest in the later year blocks...hmmmm....

 

I know when I go to the hardware store the 3" long bolt cost more than the 2" long one. I'll assume the same apples here.

 

I dont know, the older style has all the exact same bolts except the top row of bigger bolts has a slightly shorter one on each end. The center ones for that row and the bottom row is identical. 2 bolts per head are about an inch shorter. The later sets which all the big bolts are the same length is cheaper. Doesnt make much sense to me....

S is short bolt, L is long bolt and T is the tiny bolts under the intake.

Old:

TTTTT
SLLLS
LLLLL

New:

TTTTT
LLLLL
LLLLL

 

^^^Nice rendering on how the bolts are arranged. Thank you for that.

 

I fixed that for you. The newer blocks have all short bolts.

 

^^^do they? Didnt know that. Learn something everyday.

 

^^^aww CRAP!
I'm really now....

 

Jon, my machine shop had to replace my LM7 block because they broke a tap off in a head bolt hole. I’m just finding out that this replacement block appears to take all short bolts. My original block used 16 longs and 4 shorts. I had already bought the ARP bolts with the long/short bolts. Part number 134–3609. Would you know what ARP bolt kit I need for this mystery block? Is there anyway to research what block I have? Thanks for your help.

 

04 on up uses the later all short bolts

 

You need head bolt kit ARP 134-3610