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RE: Non-hypothetical question, 1098 vs. 1275

To: Bud Osbourne <abcoz@hky.com>, Mike Maclean <macleans@earthlink.net>, Kid Vid <kidjoevid@yahoo.com>, spridgets@autox.team.net
Subject: RE: Non-hypothetical question, 1098 vs. 1275
Date: Mon, 19 Dec 2005 14:26:20 GMT
Opinion

while the stock 1098 is certainly a vast improvement in terms of performance 
from
either config. of the original 948, it cannot
match the significant upper mid-range punch of the stock 1275, though it does 
quite a respectable job of emulating 1275 torque in it's lower ranges (longer 
stroke, I guess).

I have also found in my experience with both stock engines that while the 1098 
(CC))
runs more smoothly than the 1275, there
appears very little difference in fuel economy in normal town/country driving.

With both engines, bear in mind the Datsun
5 speed's first 3 gears are slightly lower than the ribcase ratios. 

So if you were to go "stoplight to stoplight"
with a HC 1275 using a stock ribcase, your
5 speed equipped HC 1098 "CC" would probably give the former a pretty good run
for it's money, assuming same diff ratios.

Of course, once you got into the higher gears where the 1275's torquier high 
midrange (and higher rpm) "punch" came in over time, it would be all over!

Anyway, this may give you an inkling of the
upgrade in performance the stock Datsun 5 speed is capable of providing, in and 
of itself, engine size notwithstanding.

However, no matter how you slice it, the
stock HC (cg) will not equal the general
increase in overall torque of the 1275 or it's
(shorter stroke?) upper-midrange and hi-rpm "revability".

Caveat....
for mechanical "smoothness" of running, the 1098 wins hands down, IMHE. And 
while all Series A motors have (to me) an extremely sexy noise signature, the 
1098
is downright "silky" in this respect.

The 1275 is usually of the thicker wall variety, except for the early '67 
blocks, so
provides for a more stiff (less bore flex, etc.) block, if you're thinking of 
performance tuning.

This having been said, I used an early '67
thin-flange 1275 with 55k indicated miles on it for Judson Supercharger testing
purposes. We beat the hell out of this
block over 3,000 miles while "dialing in" the Judson, which was subsequently
abandoned, the application being too problematic for a variety of reasons.

Anyway, this thin-flange block suffered no
apparent problems from such "mis-use".
Ran just as well for thousands more miles normally aspirated after we pulled the
blower, as it did prior to us beating the 
hell out of it!  :)

Cap'n. Bob      '60 :{)




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