velox65

iTrader: (9)

Helping a friend out since he doesn't have a account on here, he looking at getting some aftermarket heads for his 99 firehawk, however he says that in their website it says they use 04+ equal length headbolts with these heads only. Now his being 99 is the long/short. Can he use the later 04+ since the heads call for that or use the bolts his block calls for?

old93camaro

iTrader: (8)

use the bolts his block calls for which are the three length bolts on 98-02 ls1 engines.

Sales2@Texas-speed

iTrader: (5)

^^Bingo! The heads do not affect the head bolt lengths! He will need the early style (long and short) bolts, assuming his short-block has never been replaced.

velox65

iTrader: (9)

That's what I thought, their website threw me off. Apparently he's looking at some Procomps, which I'll keep my opinion to myself as he's set on them.

Heres a except from the site
"Unlike the early GM heads, Procomp Electronics heads use common length head bolts / studs.
Starting in 2004, GM heads went to the same common length head bolt arrangement.
By using bolt / stud registers that are all the same thickness, equal clamp load is created all the way around each cylinder. "

But I agree with you all, I don't see why they would change that.

bww3588

iTrader: (49)

If they are an aftermarket casting, they could have raised or lowered the bolt registers like it says to use all short bolts regardless of the block.

velox65

iTrader: (9)

True, well I guess he can either order them and we can Check bolt lengths or call em and see what the deal is.

Would that even be safe using post 04 bolts on a pre-04?

Sales2@Texas-speed

iTrader: (5)

A decent theory, but what happens when you have an '04+ block that needed all short from the factory...now you need a "custom" set of head bolts? I'm betting against it (and don't find any such set in a search of the interwebs).

bww3588

iTrader: (49)

just a thought. it's ProComp...who knows what they actually mean.

velox65

iTrader: (9)

Good point, I'll just have him call. but I do believe whoever typed it just messed up.. Cause they'd be cutting out a huge market otherwise.