Engine Decisions...Fix, Rebuild, Replace???

[Longhorn 70]

I have a 70 Longhorn with a nice body and chassis that I have owned for almost 30 years and it was my deceased Uncle's before I bought it. It came with a 350 4V and a T350. When I bought it, a manual with granny was in it. Now it has a 67 Olds Toronado 425 in it that I rebuilt 25+ years ago that has a lot of miles on it. The olds still runs but is getting tired. There is a slight, low knock in it and the oil pressure fluctuates with the knock...... I really like the smoothness and power of the Olds but don't like the costs associated with rebuilding it.

I am going to pull the motor this weekend and mic the crank main and rod journals. I will also verify the connecting rods are the proper size. If all looks OK and is within spec, I plan on replacing bearings and oil pump and bolting it back in. Besides the aforementioned, I will replace the rear main seal and front crank seal. As well as the front transmission seal.

Anything else I should do while I am in there??? I feel I am forgetting something. OR should I bite the bullet and rebuild the whole thing? OR, again with the ORs, should I replace with a small block and be done with it???

Thanks in advance for the voices of reason and consideration.

[Lattimer]

Originally Posted by Longhorn 70

I have a 70 Longhorn with a nice body and chassis that I have owned for almost 30 years and it was my deceased Uncle's before I bought it. It came with a 350 4V and a T350. When I bought it, a manual with granny was in it. Now it has a 67 Olds Toronado 425 in it that I rebuilt 25+ years ago that has a lot of miles on it. The olds still runs but is getting tired. There is a slight, low knock in it and the oil pressure fluctuates with the knock...... I really like the smoothness and power of the Olds but don't like the costs associated with rebuilding it.

I am going to pull the motor this weekend and mic the crank main and rod journals. I will also verify the connecting rods are the proper size. If all looks OK and is within spec, I plan on replacing bearings and oil pump and bolting it back in. Besides the aforementioned, I will replace the rear main seal and front crank seal. As well as the front transmission seal.

Anything else I should do while I am in there??? I feel I am forgetting something. OR should I bite the bullet and rebuild the whole thing? OR, again with the ORs, should I replace with a small block and be done with it???

Thanks in advance for the voices of reason and consideration.

If all it really needed was bearings, I would just do what you are planning. However, this is usually where reality jumps in and you find out you need a lot of machining work, and it turns into a total rebuild whether you want to or not. If the bottom is worn out, I'd be willing to be the top is close, and you may find yourself doing heads/cam/etc very soon.

Maybe its just my luck, but every time I try to go cheap and just do the minimum, I get bit for it and wind up paying twice as much and doing twice as much work before I'm done. I need to learn to listen to the advice I give others.......

Anyways----I see either total rebuild or crate engine as the best options when you have an ailing engine. From there, its a matter of what you want/emotional attachment/cost.

$2000 will get you a 300HP 350, new with warranty. I've been thinking that direction myself, instead of trying to get decent power from the old 327 I have. My issue right now is an emotional attachment to the 327. I've always wanted one, and now that I have one, its a low HP version. The 350 is like being John Doe............way too bland and nothing special.

[Longhorn 70]

Originally Posted by Lattimer

$2000 will get you a 300HP 350, new with warranty. ...... The 350 is like being John Doe............way too bland and nothing special.

Yeah after I'd posted I saw a few others with the same decision. I agree with your quoted line above. I made a list of pros and cons. That was a con to the small block.

I'll have to find out what is really wrong before I act. Then see how much I get for allowance.

[MidLifer]

Get a crate 350 from JEGS and live with the blandness! And the lack of headaches!

[Lattimer]

Originally Posted by MidLifer

Get a crate 350 from JEGS and live with the blandness! And the lack of headaches!

After looking around I think I would buy from Pace.

http://paceperformance.com/i-5146377...-shipping.html

[Coley]

These engine rebuild or replacement questions are always interesting in terms of the range of feedback.
That 425 Olds Motor you've got is a pretty damn cool motor to have under the hood. Way up there for 'hood up' factor at the local 'show and shine' than the standard 350's....and 2-3 times (at least) for cool factor than the LS motors.
If cost is a big driving issue you have to look at the difference in cost between the choices, not the total cost because either way you will be spending something at the end of the day.
So, gut check your own personal requirements and preferences on this...ie: power? torque?...whats your personality? If you are conservative and nervous mechanically...maybe go with the LS option. If you like the factory look then go with a Jegs 350 or similar. If you like something different with great power...maybe redo the olds.
Keep us posted...and good luck!!
Coley

[MARKDTN]

I would almost go another way. I wouldn't put a Pontiac or Olds or Buick or Cadillac in there if it wasn't, but since it is already there I might keep it. I will be surprised if there isn't some bottom end damage. Those BB Olds do not like RPM. I think you will have to at least redo a rod or 2-but I might be wrong. I would be tempted to find another Olds motor. There was a 350 Olds crate on Ebay a few weeks back. If you did that you would need an intake, but everything else should work depending on exhaust manifolds. Or find a 455 Olds and put it in place of the 425.

[cdowns]

build yerown then you can go thru the 1000 miles of misery trin ta fix it and throw it away and then buy a crate

spend some time in the engine section there are plenty of examples of bounced rebuilds there that have no warrentea

[PanelDeland]

I think I would pull it and look.If it needs much throw a 350 in it and start saving and getting ready to rebuild the 425 or a 455 replcement.That way the truck stays driveable and you can still work toward the Olds "WOW" factor.

[vertigo]

Originally Posted by PanelDeland

I think I would pull it and look.If it needs much throw a 350 in it and start saving and getting ready to rebuild the 425 or a 455 replcement.That way the truck stays driveable and you can still work toward the Olds "WOW" factor.

Agreed. Pull the olds, set it aside and drop a 350 crate in it for now. Then when you have the time/money, start rebuilding the 425.

[Longhorn 70]

Originally Posted by vertigo

Agreed. Pull the olds, set it aside and drop a 350 crate in it for now. Then when you have the time/money, start rebuilding the 425.

Yes I am leaning this way. If there isn't too much wrong with the Olds.... It'll get rings, bearings and an oil pump. I did the rebuild on it 25 years ago and have done a cam and lifters and had the heads done since.

If there is too much wrong to do these simple things.... ANY cheap small block Chevy or Olds will go in. I picked up a set of small block Chevy mounts Just In Case from a board member. He also has a small block Chevy cheap....

Thank you guys for being voices of reason and assurance.