I am restoring my 1958 caddie biarritz for concours
I bought 2 engines:
What happened to your original engine?
1 Has been rebored at .030 with a .003 tolerance. It seems
to me that it only needs piston rings , bearings , and gaskets..
2 The cylinders are std but the cylinder wear (tolerance) is at .008 Option 1 just replace std rings and bearings
Option 2 reboring to use .020 pistons and rings
Option 3 cylinder sleeving to get it again to min tolerances in STD leave it std?
Which will be better for a concours car and which engine components
do you recommend me to replace..?
Is the car more valuable if the engine is STD?
Is an Std engine as reliable as a rebored one?
Any issues with the HP or the engine working temperature?>
No, not if your radiator is in good condition. Have the engine's bores honed with a 220 grit stone, no coarser than that, the rings seat more quickly. Some shops hone the bores with a 100 grit stone, and the engine uses oil for about 10,000 miles and runs hotter because of the increased friction. I only use the 220 stones on my engines for the last 35 years.
For concours, to be absolutely sure, I would stay with the standard bore. .008 won't be a problem with new rings. I have never had a problem with doing this. The only time you would have to have an engine dry sleeved back to standard would be if you were at .060 (usual rule of thumb maximum overbore) and still had excessive piston to wall clearance).
More engine questions
Which type of heads exist originally for the 365 engine ( I have heard that low and high compression ) How do I Distinguish them ?
By the casting number?
The only compression ratio listed in Motor's Manual is 10.25 to 1 compression. With tri-power option you might have have slightly bigger intake valves for that option. A possible exception to that is if the car was made for export, around those years they had a lower compression option such as 8 to 1 because other countries did not have high octane gasoline available in those years. Sometimes to compensate a thicker head gasket was used for export also.
Any experiences with the mild mod cam?
I would stick with the standard cam. A heavy car needs to have maximum torque on the low end of rpm's. Too much increase in cam duration destroys fuel mileage and makes the car slower from takeoff unless you have a higher stall speed torque converter. Any cam duration that exceeds about 240 degrees duration will tend to start having a "raggy" idle. Either use the standard cam or I think a separate cam is listed for the Eldorado with tri-power option, I would use either one of those two only.
Any good source for the realiable and nor so expensive engine parts?
Go to http://ebay.com they often have piston rings and bearings, or you can likely do one-stop shopping at
Northwestern Auto Parts, 1101 S. Division St., Grand Rapids, Michigan. I think their website is at