obfpd172

iTrader: (1)

I found a set of ported 862 heads with 2.05/1.6 valves that I want to buy was told they were done buy MTI but no paperwork to prove one way or the other one cylinder has some damage to it and looking for opinions to weather milling will clean them up. The bad thing is I dont know if they have been milled or not before no markings stamped we can find. Im looking to bump up compression and pistons have 3cc reliefs cut in them.

obfpd172

iTrader: (1)

Has to be one person that works in a machine shop

tech@WS6store

iTrader: (2)

Milling will fix that. Every .006 off is 1cc. A clean up might be .006 to .010, which is fine.
You will need the composite head gasket for those heads BUT they are on a HUGE backorder from gm. We have a better solution. Mls gaskets made for the notched deck heads. They are $50 for the set. (plus shipping)

You can email me with any other questions.

truckdoug

iTrader: (25)

they should measure 4.75 +/- .002" from the deck to the rocker cover surface.

ws6store is correct, that head is notched so you either need a composite gasket or have it welded up.

my preference is to weld them up to use an MLS gasket and at the same time flow some 4043 into that damaged area.

this is all depending on what they are milled to currently and your application.

good luck!

tech@WS6store

iTrader: (2)

You didnt catch all that we said then ;-)

We have 862 head gaskets for both ls1 and 6.0l bores. They will work up to 3.905 bore cyls and 4.030 on the 6.0.

$50 for ls1/5.3/4.8 and $70 for 6.0 for the set.

obfpd172

iTrader: (1)

Thanks for the replies as far as measuring if they have been cut I might need a little guidance on that

Darth_V8r

iTrader: (4)

Surest way to know is to have the chamber volume checked by a speed shop.

obfpd172

iTrader: (1)

Will checking chamber size be true if they have been blended due to the larger valves

obfpd172

iTrader: (1)

Truckdoug can you go into a little more detail on measuring

truckdoug

iTrader: (25)

yeah take some dial calipers and measure like this

obfpd172

iTrader: (1)

I will give that a shot thanks

64post

iTrader: (5)

How did anybody get 2.05 valves to work on an 862 head? Some say 2.00 is max for that head. Obfpg, did you actually measure the the heads of those valves?

obfpd172

iTrader: (1)

Should have the heads in my possession by the end of the week but this is the picture sent to me.

cookseyb

You have to replace the seat, 2.00 is all you can put in the stock seat. Just got through doing it the stock head will also accept 1.56 exhaust valves FWIW

64post

iTrader: (5)

Oh, the seat change allows that valve.

obfpd172

iTrader: (1)

So I put the calipers on the heads today looks like they have been milled .030 so my next question is can .010 more be cut off to clean them up. I don't believe I will have ptv clearance problems my pistons have -3cc valve relief cut in them and cam is 230/234 .601

tech@WS6store

iTrader: (2)

A clean up is normally .005 - .006. Id recommend that at most...going more your head deck gets thinner and youll def want to measure for pushrod length. You should be ok with ptv issues with valve reliefs. If not either an adj timing set of pair of cometic .060 gaskets would do the trick.

obfpd172

iTrader: (1)

Definitely will measure pushrods just want to make sure intake will line up without any issues

obfpd172

iTrader: (1)

Tech@ws6store. Looking back at our discussion can you explain the notch deck head I guess I don't know what your talking about

tech@WS6store

iTrader: (2)

Thats the difference