coolant crossover pipe bolt sizes

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Sep 22, 2011 | 12:38 PM

jks67ss396

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coolant crossover pipe bolt sizes

Hey guys,

Im looking for some clarification on what size bolts i need for the rear crossover plugs and the front crossover pipe.

Heres some info i found here

LS1 rear coolant bolts (on back of heads) (HFH m6x1x30) = 11516425 (formerly 11514008)
LS1 coolant bolts for front pipe = 12561089
LS1 coolant crossover pipe = 12562169

So are the bolts for the back plugs actually different between the front and back?

And, are these part numbers actually correct? 11516425 and 12561089

And, cant you guys tell me the bolt sizes? m6x1x30 on back? and on front?

thanks

Sep 22, 2011 | 01:05 PM

MeentSS02

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The front bolt size is correct - I just measured the stock ones on my LS1 the other day, and that's what I came up with. I've never looked at the rears on mine though, so I can't say for sure if the bolts (or studs as they are on mine) are the same back there, but I can't imagine them being different seeing as how the heads are mass produced - it would make more sense to make the hole diameter, depth, and thread pitches identical front and rear.

Sep 22, 2011 | 01:56 PM

jks67ss396

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Hey Steve

So, the front is m6x1x30?

i cant imagine front/rear being different either...

thanks

Sep 22, 2011 | 02:37 PM

MeentSS02

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I'll double check the measurements when I get home, but it was definitely an M6 x 1.0, and it was pretty long, so the 30mm length looks correct to me.

Sep 22, 2011 | 02:39 PM

jks67ss396

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thanks man

ive got 3 30mm bolts and 4 40mm bolts. (measured total length.. thread + head)

might be missing one of the 30's and the 40s look like they will work, but im sure ill need them for something else...

again, thanks for all your help

Sep 22, 2011 | 06:17 PM

sjsingle1

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used 30mm front and back on mine

Sep 22, 2011 | 06:34 PM

jks67ss396

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30 mm under the head or total overall length?

thanks!

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Sep 22, 2011 | 06:38 PM

jks67ss396

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just making sure

thanks!

Sep 22, 2011 | 08:24 PM

#10

MeentSS02

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I measured 34mm under-head length on the stock studs, so 30mm will be a little shorter, but should still have plenty of thread engagement.

Sep 22, 2011 | 10:36 PM

#11

Paul Bell

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The front and rear threaded holes in the heads are identical.

Retain and use the coolant tubes to the back of the heads. The rear cylinders can use all the cooling help they can get.