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Re: camshaft recommendations..
Posted by: chris ()
Date: January 30, 2018 05:29PM

Grandpacorvair Wrote:
-------------------------------------------------------
> texas yenko dude Wrote:
> --------------------------------------------------
> -----
> > I've got a TB-20 in my 64 Spyder. It has a
> > 150/180 hybrid turbo and 63 150 heads. It runs
> > great.
>
> How did you use 62/62 heads on a 64 engine? I
> thought it was a bad idea given the longer stroke
> of the 64?

Enlarge the chamber openings for the bigger diameter cylinders. Otherwise, off the top of my head, I'm not sure the volume difference between the two. The early turbo chambers are not open either so they promote a better burn.

'65 Monza 4 door
4 speed
110hp
Gardner, KS

Heart of America Corvair Owners Association

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Re: camshaft recommendations..
Posted by: caroseiii ()
Date: January 30, 2018 05:31PM

Increases compression when using 62-63 heads on 64 turbo. Some people like it but requires water injection or other pre-ignition control. GM would not have redesigned the heads if they could have warrantied the existing design! This is why many use the 64 95hp heads with the corrected chamber volume for that purpose rather than early turbo heads.

Crawford

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Re: camshaft recommendations..
Posted by: Nickshu ()
Date: January 30, 2018 08:11PM

The only big difference on the 145ci and 164ci heads are the outer diameter of the jug, the later cars used a larger outer diameter which as noted above can be machined easily to accept LM jugs.

The 62-63 Turbo and the LM 95HP heads can be made to have matched chambers with a little machining, as well as to set the desired CR. It's cheaper for the right side head to machine a 62-63 turbo head to match the LM jugs because you already have the turbo oil drain in place and don't have to add it, however if you don't care about originality you can put the drain into the valve cover as many have done.

On my engine I actually have a 62-63 turbo head on the right side and an LM 95HP head on the left side. They have been machined to have matching chamber volume and visually look almost identical. Runs great. You do have to run a little brass adaptor for the thermistor on a 95 head but you don't see this anyway b/c its hidden inside the shroud.

Closed chamber heads are desirable for reduced pinging and being able to run a slightly higher CR for better off-turbo performance.

Mine are cc'd at just over 8:1. The factory CR for '64 was 7.4:1.

Nick
_______________________________________________________________________
1964 Monza Spyder Convertible #435 - Rotisserie restored - Check out my restoration thread here: [corvaircenter.com]
Recreational Mechanic/CORSA Member/COG Supporting Member/US Navy Veteran
Northern Colorado, USA



Edited 2 time(s). Last edit at 01/30/2018 08:16PM by Nickshu.

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Re: camshaft recommendations..
Posted by: gnvair ()
Date: January 30, 2018 08:53PM

I have run 62-63 turbo heads on a 164 engine with the 65-69 cylinders. Compression is only increased when you start cutting the head gasket registers down. If you have an uncut pair and just open the register bore you will be fine with compression.

Lee J

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Re: camshaft recommendations..
Posted by: 65180 ()
Date: February 01, 2018 12:24PM

I am running a TB 20 in my 180 with a Rajay/EM turbo and a Weber 40. It has a real nice mid-range even off boast. Soon to upgrade to 140 heads and Weber 45. Also considering upgrading to a TB-30 cam.

Mike Lake
Tucson, Az
65 Corsa 180
65 Corsa 140 sold
66 Monza PG
66 Monza 4sp sold
61 Lakewood sold
61 La[corvaircenter.com]

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