[dmdoneen]

I’m restoring a ’65 GTO with the original 389. The engine was rebuilt in 1978 at 128k miles, but I’m not sure exactly what was done. It has about 40k miles on the rebuild and ran strong when I started the restoration.

I’ve removed just about everything from the outside of the engine to clean it up and paint it. I installed a Viton rear main seal and purchased a new oil pump, shaft, distributor gear and timing chain. The fuel pump and water pump are new, but I’ll install stainless divider plates for the water pump.

Should I replace the lifters and push rods, or just clean and check the ones that were installed? The cam lobes look pretty good, as do the cylinder walls. Thinking about removing the heads and having a machine shop check the valves, seats and springs. Also considering replacing the press-in rocker studs with the screw-in type, but will that require polylock nuts? (I’ve got splash shields and original valve covers).

I’m at the “while you’re at it” stage and looking for advice. Are these extras worth doing and are there other things I should consider? I would appreciate any input from those who’ve been there. Thanks.

[Tim Corcoran]

If your happy with the way the engine runs then I would leave it alone and run it. If it ain't broke don't fix it.

[pjm64tempest]

I am restoring a 64 tempest. I purchased a 389 in strong running condition to replace the 326. I had to make some of the same decisions. The way i looked at it is do I really want to gamble? Do I have the money? Do I have the time?
I decided since I have the money and time and don't like to gamble I would rebuild.
New cam, lifters, timing chain, oil pump, Pistons, H beam rods, stainless valves, heads reworked and rebuilt,
I even replaced the 4barrel with a 66 tripower.
My way of thinking is if i can afford it I will do it right while I have it apart. Just my 2cents worth. Anything worth doing is worth doing right!

[Tim Corcoran]

There is nothing WRONG with leaving a good low mileage motor alone. Everyone has a different idea of what doing it right means. I think you would be throwing away money rebuilding a perfectly good motor. Most of the time these old classics don't get driven all that much. You may never wear this engine out as it is. And if you rebuild it you may end up with a ticker or another problem.

[lust4speed]

I agree with Tim. The engine should match its intended usage. If this is a pure cruiser and show car, most of the additions will only waste your money. Even the pressed in rocker studs are good up to at least 260 pounds open pressure, and a stock Pontiac valve train will be way, way under that figure. Drive it conservatively, and it will easily go an additional 100,000 miles or more just the way it sits.

Now if you plan to hot rod or race it, then it does pay to build in a safety margin. Trouble is that this leads to the bottomless $$$ pit of engine improvements - and there is no 12-step program since it becomes a life long addiction with no cure. If your engine hardly ever sees the top end of passing gear, save your money.

Now a couple of exceptions:

Since you are going with the new oil pump, make sure the pickup is permanently attached to the pump body. I prefer a couple of small welds, but there are many ways to insure the pickup doesn't come off and lay on the pan bottom.

Only thing I might worry about is the previous rebuild probably didn't include hardened exhaust seats, and that 40,000 miles would be enough to have the valve seats eroded into the head with the low-lead and then no-lead gasoline - which would mean it's time to install the seats. Here's where that pit starts to come into play. Accomplishing a valve job including hardened seats should include new single piece valves. Original two piece valves last forever until they are messed with, and then they have a nasty habit of dropping the head off into the combustion chamber.

[zeebo]

well a rebuild from 1978 and not sure what was done? tough one...me? id go through it and make sure all is ok and up to snuff. esp the heads with hardened seats. are you restoring the car back to original, or? they have some new cams, etc today that they didnt have 35 yrs ago...and new technology for bearings, etc...at least pull your caps and check conditions and tolerances. heads id get redone...and prolly drop in a bigger cam....might as well make all this work enjoyable..

[dmdoneen]

Originally Posted by Tim Corcoran

If your happy with the way the engine runs then I would leave it alone and run it. If it ain't broke don't fix it.

Tim – The motto I like to use is: “If it ain’t broke, don’t break it.”

Mick – I will take your advice on the oil pump pickup, especially since my dad had his fall off soon after the engine in his truck was re-built. I’ll use the set-screw with Loctite method I saw in another post here, since I don’t have a welder.

Zeebo – I am restoring the car to original and will use it for cruising and car shows.

Decided to remove the heads, and already got a quote for a valve job with new seats. I’ll make sure they are hardened seats and one-piece valves. I won’t mess with the cam, and will probably just check the torque on the caps.

Thank you all for your help.

[My442]

"If it ain't broke, fix it until it is"

[dmdoneen]

Originally Posted by My442

"If it ain't broke, fix it until it is"

Funny because it's so true, as least with me anyway.
I may just have to start using that one.

[Scarebird]

Originally Posted by Tim Corcoran

There is nothing WRONG with leaving a good low mileage motor alone.

^^^ THIS ^^^

[geeteeohguy]

I agree with Tim. You already did what you needed to: rear main and re-seal. Leave the rest alone. I rebuilt the 389 in my '65 GTO in 1981, and it has about 50k miles on it. It could use a repaint, but it's still leak free, amazingly enough (good old asbestos rope seals!) Age does not degrade lifters, cams, etc. if the engine is clean inside and taken care of. Leave the internals alone. I had the '67 400 out of my '67 GTO last March for a rear main and reseal job, and when I pulled the main and rod caps, I noted that the bearings were like new (77,000 miles on my 1988 rebuild). I just put it back together as it was. Nothing wrong with "old" parts that are within tolerance and in perfect serviceable condition.