Titan22

I’m installing a set of Trick flow 215’s on a 2003 ls6. Looks like a change was made in 2004 on the bolts used? Is that a head change? Trying to figure out which apr bolts will work with my situation.

Thx Rich

Bill Curlee

Rich

Yes, that block is different and takes a different length set of bolts/studs. Im NOT a parts number guy but someone should chime in.

Ive done quite a few head swaps and over the years, I have learned that using the ARP HEAD STUDS makes a very nice install over the bolts or TTY OEM crap.

If I remember correctly the change was making the two outboard (front/rear) bolts the same length as the other bolts.





BC

Titan22

I believe looking at the trick flows that they only have two different length bolts instead of three. I’d assume then that the block is the same but GM changed the depth of the bolt holes on those four? Looks to me that I should change to the 2004 plus rather then the 2003 and back.

493lszosix

Bill is correct it’s the block that’s different the 04+ use same length so you will need the 03 different length bolts, I’m running the tfs 215’s on mine, will be interested to hear the results once you get it done!

Bill Curlee

On the 97-2003 LS Engs the front and rear head bolt holes on the ends of the block are shorter than all the rest of the bolts.

A NOTE and WARNING!!!!

ALL of the head bolt holes are BLIND HOLES. They MUST be clean and dry. If there is ANY liquid or dibres in the holes, when you torque in the head bold, it can rupture the block.

DO NOT use a standard TAP to clean the head bolt holes!!!!!!!!!!!!

BC

Titan22

R
I may call Trick Flow and see what they say. I don’t see how the block could be different. If two options are available, one with three different size studs and one with two that must be dictated by the design of the head. The deck is always flat and everything extends above the deck, unless for some reason those two extend more or less deep into the block?

Titan22

Bill, so those four don’t extend as deep into the block as later models? Correct.
Thanks for your input.

DetroitPlac

Careful, it was a rolling change in 2003. My car was a mid-year 03 and needed the shorter top corner bolts (3 bolt kit). I've heard of later 2003's needing the 2-bolt kit. It's best to just pull the head bolts to see for yourself.

You're right, the holes aren't as deep as later cars.

And repeating what Bill said, spend more time than you think necessary to clean the holes. I found that twisting paper towel into long thin strips worked the best at getting coolant out of the holes. "Screw" it in to clean the threads. I probably ran over the holes 10 times before they were perfect. And I vacuumed with a shop vac before installing the heads.

itsslow98

Yep, for the 03 I've been told to order head bolts when the heads come off. It's the only true way to know. Looking at my vin mine w as one of the last 1,000 vettes built in 2003.