cylinder head rebuild

[concrete52]

75 dart - 225 slant 6 - mild rebuild for the motor - going with the super 6 set up - .020 oversise pistons amd a mild cam - what can i do for my head work ? hardened exhaust valve seats ? -3 angle valve grind - take .020 milling the heads or even more? stock springs ? porting and polishing ? its a driver - thanks

 

[RustyRatRod]

Take .100" off the head. It already has hardened seats if it's a 75.

 

[pishta]

cam it, put 340 springs on it and mill it up to .100, I always heard .090 but whats another .01?

 

[RustyRatRod]

cam it, put 340 springs on it and mill it up to .100, I always heard .090 but whats another .01?

I think Charlie accidentally milled one like .125 or some such. He had already milled it some and then knocked some more off and forgot about the first time.......or something like that. lol Maybe he'll chime in and tell the story.

 

[concrete52]

.100 off the heads - that boosts compression - what do i end up with in doing this - what about .030 or .040 or .050 - whats the factors in this - trying to understand what are the limitations or to be careful with this machine work - i get quick answers but not the whole arena -

 

[RustyRatRod]

.100 off the heads - that boosts compression - what do i end up with in doing this - what about .030 or .040 or .050 - whats the factors in this - trying to understand what are the limitations or to be careful with this machine work - i get quick answers but not the whole arena -

The compression on slants blueprints into the high 7s. Even though they are rated higher. LISTEN to what we are telling you. Knock .100 off. If you end up with a true 9:1, it will be a miracle.

 

[powerwagonpaul]

I took .030 off mine (was free and what I could afford at the time), and ended up just shy of 8 to 1. 7.97 or something like that.

 

[KosmicKuda]

OK if I ask a few questions too?

1964 225, freshly bored/honed +.040.
I guess for now I'll be sticking with the 64 head. I'm on board with the .100 off the head.

The original head gasket I took off was steel. (0.020?) Are they still available?

Pushrods: I read that stock ones can be reused. Is it necessary to get shorter ones?
If going with stock length rods and longer aftermarket adjusters, does the top of the rocker arms have to be milled for locknuts? It seems it would be almost easier and maybe cost effective to just get new pushrods .100 shorter than stock from Summit. Just give them the length and they make them.

If using a composite head gasket (Felpro), isn't that going to be thicker? Like another .020 or so? So it would lose a little compression using a thicker gasket.

Wild Bill Dedman and Pishta have me thinking a turbo may be in my future in another year or so. So, not a good idea to mill the head if a turbo is in the future?

I need to work this out so I can be on the road for spring.