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1g 7 bolt head on 6 bolt block. Using L19 6 bolt headstuds?

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slowgsr

15+ Year Contributor
862
9
Dec 17, 2007
hamilton, ON_Canada
Hi from doing some searching it turns out in order to put a 7 bolt head on a 6 bolt block you need to drill the head out to 1/2" for the 12mm stud clearance. I have my head installed, torqued down etc. I first went to drop it on the arps and the head binded up on the 2 center holes. I then wiggled it off (no biggie). I then just unscrewed the middle head studs and dropped the head on and thread the headstuds in from the top.

Torqued it down everything went fine. Now I know oil flows through one of the headstud holes (for a short bit) I just want to be sure I'm not restricting oil flow to the head due to the larger stud. I did do the oil port mod to the head though and the headstud clearance issue was only with the center 2 holes.

So guys am I going to be alright here? I really don't want to buy another $200 head gasket unless I absolutley have too.

It my be slightly difficult for me to remove the head though. Doh! It threaded in fairly easy down into the block with the Allen key on the top of the stud, took slight effort but nothing serious and it was only on the center two.

Thanks guys!
 
check your oil pressue at 2 spots.. one being on the head and the other before the head.. and let that be your guide.
 
I'm going to measure the head bolt hole that has the oil passage on a stock 6 bolt head I have on my car now and see if I can find a measurment for the 7 bolt heads just to compare.

If anyone has a 7 bolt head and a vernier it would be awesome if they could measure the headbolt hole size on the one with the oil passage!
 
Im wondering the same thing at least on what size to drill all the holes to. I could measure that for you tomorrow with the mic. I went to put my head on today and the same thing happened only I didnt force it LOL. P.S. I sprayed copper gasket spray on all surfaces do i need to clean and respray or is it ok to put it together after it dries?
 
I ended up just running it. I did however do oil port mod #1.

I have not checked oil pressure at the head, however.. there is no ubnormal lifter tick or anything that would lead me to believe theres insufficent oiling. I use 5w30 oil, I ported my relif valve on the pump and see a max of 75psi. Im using Kelford 272s, Kiggly beehive springs/retainers, Ferrea valves,seals,guide,locks and revised lifters/stock rockers.

Thats what I use, 7 bolt big port head (undrilled), with 6 bolt block and L19's, With the L19's, I dropped the head on with the outside studs in, then dropped the headstuds in and threaded them in once the head was on. I did notice however that the hole with the oil feed had slighly more 'slop' then the other holes.
Just saying what I have done, and what has worked for me.
 
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