best way to lower comperssion?

[scottiedawg66]

I need to lower compression and have a few silly ?s

1) what is stock compression on a '65 200?
2) is there a difference in a '65 '66 head?
3) whats the cheapest way to lower compression?

 

[MustangSix]

I need to lower compression and have a few silly ?s

1) what is stock compression on a '65 200?
2) is there a difference in a '65 '66 head?
3) whats the cheapest way to lower compression?

1. Stock CR should be 9.2:1

2. There's not many noticeable differences between a C5 and a C6 head that I can recount. Maybe the brothers Schejdahl can elaborate.

3. If the intended use is a turbo as you have listed in your sig, you need to get down in the 8:1 range. If you bolt a late 200/250 head on with an off the shelf composite head gasket, you're there.

 

[pedal2themetal45]

HI YA SCOTTIEDAWG66
Mustaingsix beat me to it..
If you don't want to take the bottom end apart then the 250 head, I don't thank just gaskets would do it... If your going to take the bottom end apart then dish the pistons.
I like the last option but it don't work for the motor just the brain
Tim

 

[CZLN6]

Howdy Scottie:

Jack's right. There is no discernable differences between a C5XX & a C6XX casting- with one exception being a Calif emission head- C5DE-A. It was designed to use with the early Calif smog pump style emission stuff. It has injector tubes inserted into the exhaust ports in the head.

Use any late model 200/250 head of D7XX or later. They will have a 62 cc chamber, as well as other improvements useful in a turbo application. Your '65 & '66 heads will have 52 cc chambers. Use a FelPro composite replacement head gasket for better sealing and a further lose of CR. The composite head gasket is also the cheapest way to go, but it will onlty lower the CR about .3 (IE, 9.2 to 8.9:1 CR). It is not the best.

Adios, David

 

[scottiedawg66]

thanks for the knowledge

 

[Anonymous]

I hvae this odd feeling that people would like to see you punch yourself in the face