Author Topic: Engine mod - thoughts?  (Read 717 times)

bcmiller

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Re: Engine mod - thoughts?
« Reply #15 on: April 25, 2018, 09:55:55 PM »
Yeh I am an old circled tracker, from a young age worked on those cars. Didnít get to drive as much as I wanted to though.
Bryon / 1968 Camaro SS 396 - now 468 ci, M21, 12 bolt
Looking for 68 Camaro with body number NOR 181016

camaroboy68ss

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Re: Engine mod - thoughts?
« Reply #16 on: April 26, 2018, 07:34:34 PM »
The 186 and 462 heads are relatively easy to find.  Most are of the 1.94 variant which isn't a big deal.   I never run a set of old heads without completely going through them, and for me that means new valves, seats and guides, positive seals etc...  While doing that it's not a big deal to upgrade to the 2.02/1.60 valve arrangement.   As far as I'm concerned, I'm paying for all this stuff either way so it's a no brainer. 
  So don't pass up a set of heads just because they're 1.94's, chances are they'll be priced cheaper anyway, and smart money says you'll be sending them to a shop for a rebuild so.....   
 
.

I used to always have same thing done with old heads, something i learned from my grandfather growing up. Until going to a new machinist for a set of heads and showed why just swapping  2.02s into a 1.94 head does get the results you are hoping for. He had 2 cut up heads from blown motors that junked the head and the ports are different in shape depending on the factory valve. To get the most out of the swap you need to do some port work to get the correct factory 2.02 performance than just slapping valves in.
Young gun with a Camaro or 3.
1968 Camaro RS L30/M20
2000 Camaro SS Convertible
2017 Camaro SS

X33RS

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Re: Engine mod - thoughts?
« Reply #17 on: April 26, 2018, 10:08:27 PM »
I didn't bother to mention this because most any machinists you go to does it, but it's pretty common while cutting for the larger seats they'll run the bowl tool down and enlarge the throat a small degree.  That's probably what you are seeing on a factory 2.02 head.

What head porters like about this method (installing larger valves in a smaller valve head) is that they can manipulate the bowl to their liking for best flow results as they have more to work with, rather than having a larger throat with less material to start with.  So there is an advantage to this process.

As far as intake and exhaust runner size, as well as combustion chamber, there is no difference.  I've CC's original 2.02 heads and 1.94's that I have here.  Nothing about them changed in that regard. 

bcmiller

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Re: Engine mod - thoughts?
« Reply #18 on: April 26, 2018, 11:44:07 PM »
As far as intake and exhaust runner size, as well as combustion chamber, there is no difference.  I've CC's original 2.02 heads and 1.94's that I have here.  Nothing about them changed in that regard. 

Not directly related to the post, but have you ever checked any 487X heads? :)
Bryon / 1968 Camaro SS 396 - now 468 ci, M21, 12 bolt
Looking for 68 Camaro with body number NOR 181016

ko-lek-tor

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Re: Engine mod - thoughts?
« Reply #19 on: April 27, 2018, 12:12:37 AM »
As far as intake and exhaust runner size, as well as combustion chamber, there is no difference.  I've CC's original 2.02 heads and 1.94's that I have here.  Nothing about them changed in that regard. 

Not directly related to the post, but have you ever checked any 487X heads? :)
file this under "I need a boot upside the head" regret file. Way back, a guy GAVE me a set of 461X heads. The rocker stud bosses were cracked, so I pitched them in a dumpster.
Back to the OP - How 'bout a virgin set of 492 2.02s?
James to strangers, Bentley to friends
1969 SS/RS 396 coupe Hugger Orange X22 712 bought in 79
1969 SS 350 coupe LeMans Blue 713 bought in 79
1969 307 4spd. coupe Daytona Yellow 711 bought in 85

X33RS

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Re: Engine mod - thoughts?
« Reply #20 on: April 27, 2018, 03:49:44 AM »
As far as intake and exhaust runner size, as well as combustion chamber, there is no difference.  I've CC's original 2.02 heads and 1.94's that I have here.  Nothing about them changed in that regard. 

Not directly related to the post, but have you ever checked any 487X heads? :)
As far as intake and exhaust runner size, as well as combustion chamber, there is no difference.  I've CC's original 2.02 heads and 1.94's that I have here.  Nothing about them changed in that regard. 



Not directly related to the post, but have you ever checked any 487X heads? :)

I have 2, maybe 3 sets of "X" heads here and I believe one of them are 487's.  I'll dig through the stash this weekend and see.   What would you like checked on them?

I know one "X" set I have are from my 1970 400 SBC and are casting 441X.   1.94 intake but came factory with a  1.6 exhaust valve.  1970 400 was the only year and engine app they did that.

I should have said above that when there was no difference in the 1.94 and 2.02 heads as far as chamber and runner CC's, I was referring to the hump heads, specifically the 461's (no accessory holes)  and 186's (accessory holes) I have here.

bcmiller

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Re: Engine mod - thoughts?
« Reply #21 on: April 27, 2018, 04:33:11 AM »
Yep.

487X should CC more than double humps. I have several sets stashed from years ago. 
Bryon / 1968 Camaro SS 396 - now 468 ci, M21, 12 bolt
Looking for 68 Camaro with body number NOR 181016

Stingr69

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Re: Engine mod - thoughts?
« Reply #22 on: April 27, 2018, 12:35:14 PM »

As far as intake and exhaust runner size, as well as combustion chamber, there is no difference.  I've CC's original 2.02 heads and 1.94's that I have here.  Nothing about them changed in that regard. 

Did you see the extra machining operation in the chamber?  The chamber wall casting is cut wider on the intake side for factory big valve heads.