Hi Chris,
A few weeks (months?) ago the subject of four barrels came up and it
turns out there is a 390 CFM Holley listed in most of the speed shops'
catalogs. This would be a better choice perhaps for stock or near-stock
260 and 289 applications.
Performance improvement on the 260? If you assume that you're going in
for at least a full engine rebuild, do full machine work and replace all
the worn parts then you're looking at $1500 or more. For that price you
can get a decent 5.0 from damper to flywheel, plus all the parts
required to bolt it into your Tiger. The later 5.0 Mustang engines were
rated at something like 225 HP - 40% over the Tiger's 260, not taking
into account the changes in the way horsepower is quoted now vs in the
60's. You can also get many bolt-on items for the 5.0 that won't quite
work on the 260.
You can build high horsepower 260's, but why would you, unless budget
wasn't a problem? You need to have at least 20% better breathing on the
260 to overcome the 5.0's added displacement, and while you can build a
set of killer heads that have small enough combustion chambers to give
you a decent compression ratio on the 260, the same setup on the 5.0
would give you a significant additional performance increase - plus you
wouldn't need to spend a lot of time looking for elusive small-chamber
head castings to begin with.
I've built small displacement, high performance engines, and eventually
ended up near 1.7 horsepower per cubic inch. It's fun, but not cheap,
and the end result is NOT street drivable. Better to get a bigger engine
to begin with, especially considering the relative availability of
parts, and keep the state of tune mild enough that you don't need to
zing the engine to the redline on every shift.
Best regards,
Theo
|