303 rocket

[87cuttdawg]

Would an olds rocket 303 be better than factory 307 in 87 cutlass ?

 

[fleming442]

Yes and no. 1st architecture (303-394) Olds engines have a completely different motor mount arrangement.
If you have the skills to make it happen, by all means, BE THAT GUY!
However, if you're looking for a drop in or are paying someone, run àway as fast as you can.
You can flip a running 303 to an old school/rat rod guy for $$$.

 

[87cuttdawg]

Yes and no. 1st architecture (303-394) Olds engines have a completely different motor mount arrangement.
If you have the skills to make it happen, by all means, BE THAT GUY!
However, if you're looking for a drop in or are paying someone, run àway as fast as you can.
You can flip a running 303 to an old school/rat rod guy for $$$.

What about a rocket 455

 

[fleming442]

455 got torque fo ya face.

 

[Tuffregal83]

455 will fit had one in my regal with th400 you can use the same motor plates as the 307 as I did got them out of the junk yard since mine was a v6 car
But the little 7.5 rear end didn't hold up to well ended up putting in a 8.5 GN rear end with 3.73 gear still in the car today the only thing i had problems with was the header next to the steering shaft had to tweek the tube to clear

 

[MrSony]

That will nearly drop in place, yes. It's wider than a 307, so expect the clearance between the valve cover and AC box to be tight. And don't be fooled, not all 455s are "rocket" engines. Olds stopped doing that in 75.

 

[MrSony]

AND PAY ATTENTION TO CLEARANCES AND OIL RESTRICTION PLUGS.
People ruin 455s all the time because they build the bottom ends wrong.

 

[foxtrot]

455 will fit had one in my regal with th400 you can use the same motor plates as the 307 as I did got them out of the junk yard since mine was a v6 car
But the little 7.5 rear end didn't hold up to well ended up putting in a 8.5 GN rear end with 3.73 gear still in the car today the only thing i had problems with was the header next to the steering shaft had to tweek the tube to clear

I've actually had a 7.5" live behind an early 70's 455 for years. The secret was skinny tires and no track time..

 

[87cuttdawg]

455 got torque fo ya face.

Lol

 

[87cuttdawg]

That will nearly drop in place, yes. It's wider than a 307, so expect the clearance between the valve cover and AC box to be tight. And don't be fooled, not all 455s are "rocket" engines. Olds stopped doing that in 75.

How do you know if it's a true rocket ?