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93 Cobra Compression
Posted: Tue Apr 01, 2014 5:11 pm
by vuzikis
Guys I have a tech question about the compression ratio with the 93 Cobra. All the reading I have done states the ratio for all 1987-1993 5.0 Mustang were 9:1. The combustion chambers were 60.6-63.6 using a .047 head gasket. I found on this site that Ford did milled down the GT-40 heads to up the compression on the 93 cobras. Does anyone know if this is true? Any input would be appreciated.
Re: 93 Cobra Compression
Posted: Tue Apr 01, 2014 6:20 pm
by Z282SLO
vuzikis wrote:Guys I have a tech question about the compression ratio with the 93 Cobra. All the reading I have done states the ratio for all 1987-1993 5.0 Mustang were 9:1. The combustion chambers were 60.6-63.6 using a .047 head gasket. I found on this site that Ford did milled down the GT-40 heads to up the compression on the 93 cobras. Does anyone know if this is true? Any input would be appreciated.
Not true. The compression ratio, combustion chamber volume and head gasket thickness you posted are correct and were the same in all 87-93 5.0L H.O V8s and the 5.0L GT-40 V8 in the 93 Cobra.
Re: 93 Cobra Compression
Posted: Tue Jun 03, 2014 12:50 pm
by BrentE
On the spec page of this very site it says:
Cylinder heads:
GT-40 heads previously sold by Ford Motorsports SVO with 1.84 intake and 1.54 exhaust valves. Heads were milled from 64cc down to 62.5 cc to raise the compression ratio a bit although the official compression ratio is 9.0:1 and were topped off with a set of Crane 1.7 ratio full roller rockers. Heads used a pedestal type of mounting system for the rockers. Part number for the cylinder heads is F3ZZ-6049-B up till 04/13/93 and F4ZZ-6049-B after date 04/13/93
?
If they milled the heads it seems the ratio would be up a bit... maybe not enough to round to a higher tenth or something?