Blew a drive at the end of the season and am looking at my options. Will be moving up to 500 EFI's as well, from 502's - on a Formula 353 Fastech. Bo boxes, just basic bravo ones on the back w/Latham.

Currently have a Bravo with ZX gears and std lower.

With the xtra power being added, what is the best all-around option without going crazy on upgrades?

Was planning on an XZ/X Upper with either upgraded (to xr lower gear set) or new XR lowers (they seem to be the same cost).
Mechanics told me this was best, but in speaking to an OSO reseller - he said to stay with a stock lower to be the weak link and save the upper.

My drive blew when a anchor rope wrapped around it.

XZ drive is an x upper, with an Xr lower.

seems like something else may of been wrong, loosing a drive with a bit over 400 hp

Yes - anchor line did it in

got it, xz's are no longer available new - but is likely the best solution in my uneducated opinion

The upper is the weak link in a Bravo. I would just go with Bravo X drives which are an XZ upper with regular bravo lower.

My '08 353 came with 525's and XR's with drive showers. I would think Formula installed the most robust Bravo set up they could. Why do something different?

Regular Bravo's and XZ's were used with 500EFI package. The XR's are marginally stronger than an XZ.
Reasons not to use XR's are lack of longevity for the upper gear sets and cost. An XR costs about 50% more.

Thanks for the info. I did not realize the cost differential. Also, how could they be stronger, but lack longevity as compared to the XZ's? Is the best combo then an XZ upper and an XR lower as indicated in an earlier post?

The XZ drive is made up of the X upper and XR lower.

i thought the XR upper had some other improvements over the X upper not related to the gears. I’ve spoken to at least 5 drive builders this week, only 1 indicated to goto XR’s. 3 said to stick with Bravo lowers.

My Port drive is intact, It’s got the X gears, but the original bravo tower design. So may pull it and sell.