which octane do I use?

goodnigh wrote:
>>>> I am not sure what version of the 351C engine you have since the 351C
>>>> was not offered from the factory in the 1969 Mustang model year.
>>> My book says the 290/300 HP 351 was offered as an option in '69.
>>> That has to be a Cleveland.
>> FYI: 8-cylinder engines available for the 1969 Mustang are as follows:
>>
>> 302 2V F-code
>> Boss 302 4V G-code
>> 351W 2V H-code
>> 351W 4V M-code
>> 428 4V CJ Q-code
>> 428 4V CJ Ram Air R-code
>> 390 4V S-code
>> Boss 429 4V Z-code
>>
>> Production of the 351C began with the 1970 model year and ended with the
>> 1974 model year.
>>
>> More information on the Ford 335 series engines (including the 351C) is @
>> http://www.answers.com/topic/ford-335-engine
>>
>> Yet another $.02 worth from a proud owner of a 1970 Mach 1 351C 4V M-code
>> @
>> http://community.webshots.com/album/18644819fHAehGJAjt
>>
>
> So the M code is simply a 351 4V. Could be Cleveland or Windsor.
> Then the only way to tell is to glance at the engine since there
> are obvious physical differences between the two.
> My '71 is an M code and is clearly a Cleveland.
>
> mike
>
>
>

The '69 M-code is definitely a Windsor. The '70-'71 M-code is a
Cleveland. I didn't think of this on the first read-through. Whoops.

The compression ratio for the 1969 2v H-code 351W is 9.5:1, and the 4v
M-code is 10.7:1. I'd use premium gas in the M and maybe mid-grade in
the H, listening for ping, and keeping in mind the advance curve. The
Cleveland's block is obviously visually bigger, although its deck height
is a smidgen shorter than the Windsor's. There are five versions of the
Cleveland, in all, but you'll only commonly see two. I've only seen a
few Boss 351s and one 351CJ.

There was also a 302 Cleveland, but it was only produced in Australia.

--
Jason O

Jason O wrote:
> goodnigh wrote:
>>>>> I am not sure what version of the 351C engine you have since the
>>>>> 351C was not offered from the factory in the 1969 Mustang model year.
>>>> My book says the 290/300 HP 351 was offered as an option in '69.
>>>> That has to be a Cleveland.
>>> FYI: 8-cylinder engines available for the 1969 Mustang are as follows:
>>>
>>> 302 2V F-code
>>> Boss 302 4V G-code
>>> 351W 2V H-code
>>> 351W 4V M-code
>>> 428 4V CJ Q-code
>>> 428 4V CJ Ram Air R-code
>>> 390 4V S-code
>>> Boss 429 4V Z-code
>>>
>>> Production of the 351C began with the 1970 model year and ended with
>>> the 1974 model year.
>>>
>>> More information on the Ford 335 series engines (including the 351C)
>>> is @ http://www.answers.com/topic/ford-335-engine
>>>
>>> Yet another $.02 worth from a proud owner of a 1970 Mach 1 351C 4V
>>> M-code @
>>> http://community.webshots.com/album/18644819fHAehGJAjt
>>>
>>
>> So the M code is simply a 351 4V. Could be Cleveland or Windsor.
>> Then the only way to tell is to glance at the engine since there
>> are obvious physical differences between the two.
>> My '71 is an M code and is clearly a Cleveland.
>>
>> mike
>>
>>
>>
>
> The '69 M-code is definitely a Windsor. The '70-'71 M-code is a
> Cleveland. I didn't think of this on the first read-through. Whoops.
>
> The compression ratio for the 1969 2v H-code 351W is 9.5:1, and the 4v
> M-code is 10.7:1. I'd use premium gas in the M and maybe mid-grade in
> the H, listening for ping, and keeping in mind the advance curve. The
> Cleveland's block is obviously visually bigger, although its deck height
> is a smidgen shorter than the Windsor's. There are five versions of the

To clarify - 351 - five versions of this, in addition to the aussie 302C.

> Cleveland, in all, but you'll only commonly see two. I've only seen a
> few Boss 351s and one 351CJ.
>
> There was also a 302 Cleveland, but it was only produced in Australia.
>


--
Jason