2013 Cobra Jet 427
 

Could this be a 4.125 X 4.00 SBF ?

Re: 2013 Cobra Jet 427
 

Sounds right based on 351 W block

Re: 2013 Cobra Jet 427
 

Isn't that what the 428 Windsor is now?

Re: 2013 Cobra Jet 427
 

Yes, 4.125x4.000

4.080X4.100 for the 428.

Re: 2013 Cobra Jet 427
 

Is it rated at 275 HP?

Re: 2013 Cobra Jet 427
 

425 HP, same as the COPO Camaro. Same bore and stroke, the Ford has a longer rod. Wish I had either. Dyno

Re: 2013 Cobra Jet 427
 

I was comparing the 2010 352 @ 285 hp vs. the 2013 363 @ 330 hp for the SS/GT classes.

The 2010 has a bore/stroke of 4.060 x 3.400
The 2013 has a bore/stoke of 4.125 x 3.400.

Everything else looks the same.

Using the .070 allowed overbore rule, a 2013 looks like it could also run as a 2010.

Re: 2013 Cobra Jet 427
 

Taking a 4.125 and a .060 over bore per the rule give you a 4.185 bore with a bore spacing of 4.380 this only leaves less than .200 between bores not a lot material for head gasket seal.

Re: 2013 Cobra Jet 427
 

I wish I had a longer rod to.
rawhide

Re: 2013 Cobra Jet 427
 

The 327 COPO has over a 2 to 1 rod ratio.