My 1966 Olds Jetstar 88 originally came with a 425 motor , is there any other olds motors that would be a drop in replacement for the original 425 motor that came in the car. I just bought the car minus motor, want to know what olds motor would be a drop in replacement , like maybe a olds 350 rocket from any year or 455 from any year

 

looking at a 72 350 rocket motor

 

A 330,350,403,another 425, or a 455 will fit. A 72 low compression 350 like you are looking at will not have near the performance of the original 425, you will probably be disappointed....... get another 425 or a 455 engine......

 

would going with some different heads on this 72 350 motor bump up the compression any, I know with Pontiac motors with changing out the heads on the lower comp motors get you a nice increase in comp ratio

 

The 66 Jetstar did not come with a 425, as it was not available in the Jetstar. The Jetstar came with the small block 330 engine but it could have the TURBO 400 trans as an option rather than the 2 speed Jetaway.

 

Instead of changing the heads on your 72 350, change the pistons when you rebuild the engine.

 

Correct. The only engine offered in any Jetstar 88 over the three years of its existence (1964-1966) was the 330.

Remember the history here. The whole point of the Jetstar 88 line was to offer a lower-cost opportunity for buyers to get into a full-size car within the Oldsmobile brand instead of going to a Chevy or Pontiac or Ford or Plymouth. One way this was done was with a smaller engine. If the same engine as was available in the other full-size Oldsmobiles were available in the Jetstar 88, there would have been no point in having the Jetstar 88 line at all as it would just have been a rebadged Delta or Dynamic 88 and likely would have cost about the same.

 

From the 1966 SPECS booklet:




To answer the question, any 1964-1990 small block Olds is a direct bolt-in. Any 1965-1976 big block Olds bolts in with minor changes, primarly to the exhaust.

 

And yet, in 1967 when the J88 was renamed the Delmont 88, you could get a base Delmont with a 330 or a Delmont 425 with a (wait for it...) 425.

I believe this is called "mission creep".

Interestingly, the Delmont and Delmont 425 got different VINs that year.

 

And chrome fender badges (425) to signify the larger engine.

 

SO pretty much any Olds motor (V8) will bolt right in from 64-90. As long as it is an Olds motor. The 330 is one of the greatest engine Olds ever made. Great HP from them and great durability. If yours is tired then maybe just rebuild or replace it. I have a few very nice 330 320 Horsepower engines at very fair prices. If you are looking for a big improvement then a 425 or 455 would be the obvious choice.

Just my thoughts
Larry
lemoldsnut@aol.com

 

The world changes.

The three years of the Jetstar 88's existence were unique in Oldsmobile history because it was the only time that three different 88 lines were offered. Super 88, Dynamic 88, and Jetstar 88 for '64 and Delta, Dynamic, and Jetstar for '65 and '66. I think Olds felt it was important to make clear distinctions among these cars, and if you could mix and match engines and other options, those distinctions would be lost and the point of having three different lines would disappear.

In '67 (and '68), Olds went back to two 88 lines, and so a little blurring of the lines between them wasn't unreasonable. If I'm not mistaken (and please correct me if I'm wrong), not only was the 425 offered as an option on the '67 Delmont line as you note, but such cars received "425" badging on their front fenders. I believe this is the only time in Olds history for any model line in any year that the displacement of the engine IN the car was displayed with fender badges ON the car, something Chevy did all the time.

 

Sorry, but if different lines have unique model VINs, there were FOUR 88 lines in 1967.

Delmont 88 - 352xx VIN
Delmont 88 425 - 356xx VIN
Delta 88 - 358xx VIN
Delta 88 Custom - 354xx VIN



In 1968, the 88 line reverted to three model lines:

Delmont 88 - 354xx VIN
Delta 88 - 364xx VIN
Delta 88 Custom - 366xx VIN



For 1969, there were still three, but model names slid down a notch:

Delta 88 - 354xx VIN
Delta 88 Custom - 364xx VIN
Delta 88 Royale - 366xx VIN



Not counting performance models like the 442, Olds has pretty much always had three model lines in the A-body and B-body series.

F-85, Cutlass, Supreme
Delmont, Delta, Delta Custom (or Delta, Delta Custom, Delta Royale)

 

The buying public doesn't give a crap about VIN numbers. I'm talking about what the public perceives and how Oldsmobile marketed these. People see "Delta" they see "Delta." They see "Delmont" they see "Delmont." They don't care what words come after these like "Custom" or "Royale" or anything else. Heck even Olds owners on this site often don't make that distinction.

How many times have we seen people talk about their "Delta 88" and not bother to note that it's really a "Delta 88 Royale?" How many times have we seen someone with a D-88 Royale call it a "Royal," which is a Dodge term? Shows how much they're paying attention to the words attached to their own car.

We've had people with Delta 88 Customs come on here and just call them Delta 88. Numerous times we've had people with Jetstar 88s come on here and ask a question about their "Jetstar," and they have to be asked if the car is a Jetstar I or Jetstar 88 as the answer would likely be completely different. The series name sticks in their mind, the rest doesn't.

"Royale" was an upper level trim line on the Delta 88. "Custom" was an upper level trim line on the Delta 88. "425" was an engine option on the Delmont 88. I'd imagine most people who bought a Delmont 88 with a 425 thought of their car as a "Delmont 88" and nothing more. They didn't care that it had its own VIN series.

People pay attention to the model line and ignore everything else. Delta, Delmont, Super, Dynamic, Jetstar. That's what matters.

 

We'll have to agree to disagree here.