Type of oil?

[Bankerbiz87]

We have 2 350 engines Crusaders should we be using a synthetic oil?

[SplashyLady]

Rotella 15-40 seems very popular with boat users and is priced reasonably at most retail locations.

[waybomb]

X2 on Rotella.

[throwback2]

X3 .That's what I use too.

[feeez]

X4..... switched last year

[Viper]

Qr Bbpost ....should we be using a synthetic oil?

The answer is a complicated one and depends on several variables, however, in general for your vintage and typical recreational use, it's really not necessary. Save your money, use a decent quality oil, and change it at regular intervals.

[RGrew176]

The marina where I am now located uses a synthetic blend oil.

[mjk1040]

Rotella! Comes in 30W, 40W and 15w40. Tractor supply stores carry it at the best price IMO!

[km1125]

As other say, the Rotella is very popular and has tested well - and is pretty economical to run. I personally use Mobil1 15-50 but mostly because I use it in everything else I run (at different weights). Impressive cold-start performance (but not nearly the issue in boats). I was sold on it years ago when I tore down a very-hard-run turbo motor at 165,000 miles and it looked like new.

Also, a recommendation when you're referring to your motors: Crusader also makes a 454 that is labelled "350 HP", so it gets confusing when you refer to a "350 Crusader"... you should make it clear that it's a 350 CI if asking questions or getting parts for it.

[tomschauer]

+1 on the Mobile 1. I run it in everything I own. Very slick and bullet proof.
If you switch from conventional to synthetic, the first run of synthetic will clean a lot of the sludge from your engine and make the oil look pretty dirty pretty quick. After the first synthetic change, odds are it will never look dirty again unless you put several hundred hours on a year.