I am wondering if getting lifter bores bushed on a street engine is really worth it, or is it only useful when you need solid reliability? This is on a Ford 302 Windsor.

Also does any engine machine shop install bushings? Or do I need to find special shops?

not needed unless worn out or out of round.
most machine shops can do this but alot don't,best to check with them and find out how they go about repairs.

Alright thanks!

Any ideas on how to increase oil flow through the lifter bores into the valley, do you just notch it?

Is oil getting through all the lifters? I had to notch the lifter bodys on my solid roller lifters, 351 block. It didnt take much I think just a touch with a dremmel to make the lifter line up more in the oil band. and you dont want oil flooding the rockers. I think most people use the bushed lifter bores for high doller perfect allignment racing stuff.

What kind of tool did you use to notch the bore? Also how did you know how deep and notch you were making to keep it consistent with each bore?

Whaaaaat?? That sounds like an oil pressure leak to me. Lifter bore clearance should be less than .0015.

Fords don't have the lifter bore problems that SBC does.

I install SBC bronze lifter bore linings because some SBC have lifter bores misaligned as much as .060. This fubars the valve timing. It takes a special jig to do the job.

When you install your lifter bore bushing what are you doing it with to find lifter bores off .060??


At our shop we do all our lifter bore work in a HAAS 4-axis CNC machining center and on the chevy's instead of putting bushings in we will go to .875 or .904 and in 33 years of doing performance machining we have never seen lifter bores off .060 as we have seen them off maybe .020 at the most. As if they were off .060 the lifters would have wiped out in no time. We may see one in every 50 blocks that may not clean up at .875 and there not off .060

And we do groove lifter bores as Comp Cam makes a tool for doing this procedure if your using flat tappet cams. And bushing lifter bores is not a bad thing as you are correcting the lifter bores to where they are suppose to be.

And less then .0015 lifter bore clearance you may want to rethink that one over as thats what we shoot for when honing lifter bores any tighter then that you will seize a lifter in the bore as we have had blocks come in from other shops to repair them cause the lifter bores were to tight. Some shops we machine blocks for ask more clearance then .0015

The only time I've heard of bushing the lifters is to reduce the size of the lifter oiling hole. AMC V-8s have an oblong hole due to the way the lifter galley is drilled. Somce builders bush the bores to reduce the size of the hole and keep to much oil from leaking around the lifters -- helps to keep rpessure up to the crank and reduce the amount of oil going up to the heads. The stock pump oil up to the heads a little faster than it can drain back at sustained high rpm (like road racing). Drag racers generally don't find this to be a problem -- they just run a little more oil in the pan and/or a bigger pan. AMCs like to be run a 1/2 quart over full because of this -- sixes and V-8s.

1) Hallumwillis said "Any ideas on how to increase oil flow through the lifter bores into the valley, do you just notch it?" Dumping oil from the bores into the valley is an oil leak. Call it what you want. Rebuilt SBCs already have a low oil pressure problem.

2) Using a BHJ fixture accurately locates the lifter bores with the crank/cam centerline and front to rear. I have seen a couple SBC off .050 or more. Early 70s blocks I think.

(I have also seen factory SBC cylinder bore centerlines off using the BHJ fixtures. Fubar blocks. I remember one factory 4 bolt 350 that was off so far that when bored .060 one side wouldn't touch. The bore centerline V was leaning to one side....You could look at it with your eye and see that the bores were closer to one side than the other when comparing banks. Yet it had 150,000 miles on it. Most bore machines index off the pan rail not the crank/cam centerline.)

3) Lifter clearance to the cast iron block can be less than the clearance to bronze bushed bores due to the expansion rates.

4) Even old Smoky commented that lifter clearances beyond .0015 can cause low oil pressure problems. (?)

I have often wondered why rebuilt SBCs have such low oil pressure even with tight bearing clearances. When the factory builds them with 45+ at idle and 60 at 2500 rpm down the road..... hhhhmmmmm? It's a common discussion on this board. We have one factory 350 now with 150,000 miles on it and it has more pressure than 90% of the freshly rebuilt SBC hot rods.

5) Regarding oil pressure on SBC, you might want to read what Smoky actually wrote. He is often misquoted about the 10 psi per 1000 rpm rule.

6) As for the lifter bore alignment problem wiping out lifters.... NO... If the bore center line V is off from the crank/cam centerline all it does is alter the valve timing..... another good reason to degree a cam.


As I said, SB Fords do not have the problems that Chevys do.
Just my opinions.

In your post you said I install SBC bronze lifter bore linings because some SBC have lifter bores misaligned as much as .060. This fubars the valve timing. It takes a special jig to do the job.

Now are you machining the lifter bores or is someone doing this for you as I am tring to compare apples to apples here do you machine blocks for a living????

We have a BHJ fixture for machining lifter bores and since we have bought the HAAS CNC machining center we have found our BHJ deal is not very accurate as the CNC machine as the BHJ fixture you are bolting together 4 peices of the fixture as we have found our fixture is cutting .018 towards the rear and we use to install bushings in about evry block we ever did and since we are doing them in the CNC machine we may only install 1 or 2 bushings a year and we do more blocks now then ever.

On lifter bore clearances we would not go under .0013 any less then that there will be problems as on flat tapppets they run a lot hotter on the bottom of the lifter compared to the block which would require more clearance. And on a .875 or .904 lifter being bigger you would want no less then .0015 clearance.

Andy Anderson who owns Precision Products in N.C. who builds some of the best tool steel lifters in the industry and recomends .0015 to .0025 on lifter bore clearance on performance engines.

Take a .842 lifter bore at .0015 clearance and a .904 lifter bore at .0015 and the bigger .904 lifter bore will shed more oil because of the size of the bore as there is more area to bleed oil.

And I work on a project years ago that the great Smokey was involved with http://www.powerengine.com/
and I am sure if Smokey was alive today he would edit some of his statements like Regarding oil pressure on SBC, you might want to read what Smoky actually wrote. He is often misquoted about the 10 psi per 1000 rpm.
as most of the cup guys are turning almost 10000 RPM and are runnning 40 to 45 pounds of oil pressure not a 100 pounds.

On alot of GM blocks we find that the cam and crank center lines are of up to .014 and if your going to correct the lifter bores you should do the cam tunnel first as we are sert up to blue print cam tunnels and machine for over size bearings and roller bearings.

And again we have found tha CNC machining a block id more accurate then bolting fixtures together as we have proven that.

Comparing apples to apples do you do the type of work we do as we find it hard to beleive that a machine shop owner is quoting out of a book that was written many many years ago and is not going off from hands on experiance.

We build a lot performance SBC's and have zero problems with low oil pressure and most of the engines we build we only use the standard volume high pressure pumps. And on the engines with more clearance on the rods and mains and bigger lifter bores we do use the HV pumps.

Most likley to satisfy those who bought one and think the more is better. I have a freind who thinks that 80 pounds of pressure makes a engine last longer. If he bought a GM crate engine that had a designed 30psi, he's prolly fall over dead with anger. MANY more of em out there.

You may have no failures but if I walked into a shop that machined with a HAAS I would walk right back out unless that HAAS was "not" equipped with linear ball bearing ways. Try looking into a Rebel CNC machine that uses box ways. I am not 100% sure what you are doing on that machine, if its rapid, stop, then machine movements like boring, drilling, tapping, spindle applications then I say ok with the HAAS but if its any kind of table machining like milling/fly cutting then I am running from the HAAS to a box way machine. Interesting post though. I am a tool maker but was not aware of the poor quality control by Chevrolet.

Grooving the lifter bores is nothing new. Mine are grooved. With todays oils, cam grinds, and flat tappet lifters, you need all the help you can get. You may want to just look into a set of EDM lifter (laser burned hole in the center for oil flow to the lobes).

As far as bushing lifter bores it is an expense that in many cases just isn't worth it. SBC's are not near as bad as BBC's. If you are building a serious BBC then having the bores checked in a great idea. By the time you pay to have the lifter bores bushed and the rest of the machine work done you might be better off just buying a better aftermarket block.

My problem was that with what ever cam grind and lifter put the oil hole out of the oil band. By modifying the lifter I was able to get some oil through the pushrods to the rockers. My Engine builder told me to prime the pump while I turn the engine over by hand several times. If I didnt get any oil to the pushrods the hole is not is the oil band at all and the lifters needs modified.

We aldo have a V-3 in the shop for rough machining and so far there seems to be no issues so far and as far ad the HAAS we use use to machine blocks I really don't thing block boring ,decking ETC is really not hard on those machines after 6 1/2 years of machining the back lash in the mahine is fine as we have it inspected once a year and so far no problems and if Rick Hendricks is using them in his shop and he is probably doing more then me and he seems to be happy with what they have. My machine is made to handle a 3500 pound peice of steel and whats a SBC weigh 180 pounds and Dart BBC 280 pounds or so I would say my machine has a long ways to go brgore it wears out.

We are able to probe blocks out in our CNC machine to with in a .0001 and we find GM's machining is sure a production as most 010 blocks can't be bored to blue print locations and we have bore them to the preprobed locations.