kalli

if it's something the head manufactures try to sell you it's onje thing to discuss it. if they say you should drill holes then I'd rather follow that advise.
There's a reason:
- they recommend it
- Every aftermarket gasket has the provision for it
- the heads (all of them: edelbrock, trickflow etc) are prepared for it

there's no point in discussing the need. if you don't want to drill then of course leave it off, but that's exactly then when the car overheats and noone can find a possible cure for it.

i think the reason for drilling those holes is that air can't be trapped in there.

Starfury

The supposed problem is that steam can collect at hot spots under those points due to lack of coolant circulation. Once a steam pocket forms, it's hard to get it to collapse due to the high surface tension of the coolant. By allowing a little bit of coolant to circulate, you reduce the likelihood of any steam pockets forming.

abrush

I went ahead and drilled the steam holes. Had no problems what so ever but had to drill further than the 1/4" most say to drill. I actually had to go down right over 1/2" to hit the water jacket. I got the passenger head installed. I did not have a solid lifter to check pushrod length but read online that you can take a part a hydralic lifter, fill it with washers so it won't colapse and use to determine length. I did this with an old lifter I had and when I set the preload and rotated the engine the mark was worn off the valve stem right in the center. Will someone please verify that I did this right???? I want to make sure this engine runs good when I start it.

Starfury

Sounds good to me

jojobanks

sounds good to me as long as you did the check procedure correctly. Though it suprises me, this is the first time I've ever seen someone change to aftermarket heads and not have to buy different length push rods. But then that's why I never say never

kalli

i'd say good as well. definetely on the steam holes
converted lifter is commonly used, but I think it should be preloaded by 60thou (use washers). I was planning to do that this week or next week as well.

compcams said to use a checking spring so that compresses before the one in lifter does.
but that would mean (in my opinion) no preload whatsoever

I think the best thing to do is to accept this (as ok result), put the engine together with the rodlength you measured and then re-check that once the engine is run in (after break-in and tuning period)
I'll have to do one as well this week and I'll do the exact same thing (Convert a used lifter to solid)