Bushed & indexed lifter bores = power improvement?

[BradH]

I did a search and didn't notice any existing threads that talked about this, or certainly nothing recent. Have people found power improvements going from production-line lifter bores to bushed & indexed lifter bores?

FWIW, I'm dealing w/ old Chrysler 440 cast iron blocks and solid roller lifters. The "old" block now in the car was bushed in the past, but its replacement hasn't been. The lifter-to-bore clearance is better (tighter) on the unmodified block, but I have no simple way to know how far off the indexing may be, or what the potential performance impact is (other than less control of oil flow through the lifter bores). Thx

[fordified]

Can’t say that I saw a big power increase by having my inline lifter bores corrected for a splayed valve head but my valve train definitely liked it. Unless you’re turning a lot of rpm you’d probably be better off spending the money on something else.

[PackardV8]

Answer to any horsepower gain is "unknowable." Some inline lifter bore engines are so close to blueprint, truing the bores has virtually no effect. The most common gain is said to be in the longevity of the cam/lifter interface.

General concensus is the BBC are the most likely to have the lifter bores cattywhampus and BBF a distant second.

Those who offer lifter bore truing as a service are glad to take your money either way.

Of course, truing and tightening worn bores are a different deal. Of vary little interest to most here, but the Studebaker Champion flathead 6-cylinders we sometimes build always have worn lifter bores. In the past, we could scrounge up NOS .005" oversize lifters and ream the bores back true. The NOS oversize is NLA, so we're looking at making the tooling to bush the bores back to standard.

[k-star]

https://www.enginebuildermag.com/2017/0 ... r-upgrade/

Nice write up by Ron Flood.

[nhrastocker]

...and the reason why many of the top teams take their blocks to Charlie Weston at Weston Machine.

http://www.westonmachine.com/images/kingofcastiron.pdf

[rebelyell]

As well as Charlie Weston at Piscataway NJ ... there's also Kevin Blanks at Clarksville VA (about 25 miles east of South Boston Speedway and about 65 miles due north of Raleigh NC)