TBT_DK

Hi Guys

I was just reading the "olds engine modification and tuning" book by Bob Gerometta, and i had read the Max performance by Bill T, and that raise a few questions.

Oil restrictors, worthless or a good idea, they seem to disagree.

And the con rods, Bill did not write anything about Rod oil relief, is that a good idea, or waste of time?

I understand the theory about it, but is it needed, or just a good idea?

olds 307 and 403

Don't do anything with stock rods other than properly size them. The SBO has much less bottom end issues than the 455, parts are so much lighter, even if the block webbing is lacking. The only time I wiped the bottom end, other than overheating in my was 403 revving to 5500 rpm with a unbalanced 307 crank. What are your plans with the build?

joe_padavano

The common oil restrictors that go in the cam bearing feed holes are pretty worthless, especially if you study the oiling diagram in the Chassis Service Manual. If you really think you need them, simply drill smaller oil holes in the cam bearings 180 deg out from the original ones and install the bearings so those hole are towards the crank - same effect for free.

Restrictors in the lifter feed holes ARE a good idea, but much more work so people rarely install them.

TBT_DK

A little up the power range, alu heads, KB Hyper Pistons, a mid range cam, injection and crank trigger.
Not going past 5500 anyway, was just curios about this since they seem to disagree, and Bill never wrote about the Oil Relieif in the con rods.

Further the seem to differ on bearing clearance, from 0.0015 to 0.020, and Bill write no less than 0.0035 seems like a big difference, stock was up to 0.0021 so i think i will go with Bill on this one, this should also help with oil replacement i think

TBT_DK

What size would you recommend i use for lifter feed?

I stay with the Hydraulic flat tapped, so i would need oil for those, just dont see the need for pulling to much oil to the heads, since it is full roller setup.

olds 307 and 403

If you run street miles and the oil pressure number makes a difference to you, I would use Bill's minimum number as the max. He likes them loose and your lighter pistons will help stress it less.

cutlassefi

For a small block I wouldn't go to .0035 on any part of it.
.002-.0025 on both rods and mains should work fine.
X2 with Joe on the cam bearing restrictors. Just use a good restricted pushrod and you won't need anything else.
And RPM is only one of the parameters used to decide what level of parts you'll need.

TBT_DK

Thanks guys, very helpful.

Got the pushrods on the way,I did not order restricted, is it possible to get lifters that would be restricted, or should i just find a new set of pushrods?

cutlassefi

I've never seen restricted lifters, only pushrods.