Head bolt confusion

[garethcolley]

Ive got a late type LET but my GM head is cracked. Ive just got a coscast one today but ive already bought the late type elring head bolts. Do i now need early ones as coscast were on early engines? Or is it to do with the thread depth in the block opposed to anything in the head?

[ck]

there is a search function by the way :)
take a read through this thread, it will reveal all you need to know

http://www.pngclub.com/forum/showthread.php?t=101015

[garethcolley]

there is a search function by the way :)
take a read through this thread, it will reveal all you need to know

http://www.pngclub.com/forum/showthread.php?t=101015

Cheers, im still really confused though. I have no idea which to get. I have the short ones with the washers already on the bolt. The ones i took off my GM head were the same bolt. I presume now im putting an early coscast head on it ill need long ones?

[Welsh Dan]

put your old bolts in your old head and measure how much they protrude, then put them in the new head and measure how much they protrude...

[ck]

im sorry but you clearly did not read through the link i sent you. it clearly explains the differences and the fact that its a miss match, some gm heads use early and late bolts and same with the coscast heads.

[garethcolley]

im sorry but you clearly did not read through the link i sent you. it clearly explains the differences and the fact that its a miss match, some gm heads use early and late bolts and same with the coscast heads.

I read through it mate but its a bit confusing. I dont understand how both GM and Cos heads can use different bolts? For example a GM Head (early or late) was given random bolts? This wouldnt work as the dimensions would be different? They will have all been machined to a given spec (early or late dimesnions) then the bolts fitted depending which it was.