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I need more valve lift out of my heads...

S

slimguns

New member
I am looking for techniques to increase valve lift on our L67 heads. I would like to run the Intense Stage 2 cam with YT 1.7 rockers for a total of .565/.575 lift. My machinist is already rebuilding my heads as well as a P&P job but he is not familiar with these heads. I'm trying to explain to him but he giving me the "just because someone said on the Internet" response. So, can someone explain to me how to explain to him where to make the cuts and how much?

Just tell me what other info you need. The heads will have the ZZP modified retainers, SS valves (intake enlarged to 1.9), ZZP modified retainers, 105# springs, Viton seals, P&P job (gasket match), and hopefully cut for S2/1.7 valve lift.

Patiently waiting for the gurus...
 


Tell him to take .1" off the top of the valve guides, and chamfer the newly created edges to make installing the valve seals easier.
 
I'll try that, but the new twist is the heads which I bought as part of my top swap here in the "for sale" section are BOTH cracked. He magnafluxed them today and found it. I bought them 6+ months ago.

What do y'all think? Do I dig up the seller and give him crap or is it too late? I'm pretty pissed today! I had just got into the game and paid him on the higher end of the going rate (out of ignorance at the time) for them.
 
Most 3800 heads are cracked, due to the way they were cast.

Have them do a pressure test on the heads. I'm guessing that they will be ok. They are very thick in the area where they tend to crack.
 
So people run them cracked?!

Ill have a pressure check done if I can run them like that. I knew a certain casting lot was known to crack but I thought that meant they were shot.
 
Yup. The heads on my 04 were cracked, but I've been running them anyways. I've got close to 15k miles on them.
 


I know a local that went through 8 sets to find two non cracked. By mistake I dropped one of my 01 heads off and sure enough it had cracks. The cracks are between the valves.
 
darkhorizon said:
Dont let him port the heads. 99% chance he is going to ruin them.
Click to expand...

What would you suggest then? Just a polish job, stock heads just cut for lift and 1.9 intake valve? I can't pay 1300 for the heads from one of our vendors. I planned on using the Intense S2 cam.

BillBoost37 said:
I know a local that went through 8 sets to find two non cracked. By mistake I dropped one of my 01 heads off and sure enough it had cracks. The cracks are between the valves.
Click to expand...

So run the cracked heads (w/ minor cuts for the comment above) or find some non-cracked before I complete my swap?
 


slimguns said:
What would you suggest then? Just a polish job, stock heads just cut for lift and 1.9 intake valve? I can't pay 1300 for the heads from one of our vendors. I planned on using the Intense S2 cam.



So run the cracked heads (w/ minor cuts for the comment above) or find some non-cracked before I complete my swap?
Click to expand...

That would be the best. I had some heads ported and they came out nice and I know that I didnt lose power, but they were not worth the money so far as they didnt make any gains in their own right.. also the guy said he ruined ~5 sets just to figure out what worked the best.

Shelling out money for vendor heads is my suggestion if you feel you need to have ported heads.. I have ran stock heads and ran at the top of the record boards for years, not sure why I went the ported head route... stock worked fine for me.
 
GTPpower said:
Tell him to take .1" off the top of the valve guides, and chamfer the newly created edges to make installing the valve seals easier.
Click to expand...

So I talked to him again telling him just what you suggested. His response was that "the only way to get more lift is to cut the spring pocket or a longer valve." Whose right/wrong/crazy? Someone please be a tie breaker. He supposed to be the best in town so I'd hate to move the work but I'm at a loss and stuck as he is standing strong.
 
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