Benefit going to 55mm cam in BBC

[Racing68]

Is there a good benefit vs cost in going to a 55mm cam in this bbc. Engine is 598 cid pull truck turns about 76-7800 rpm, 375cc profiler heads, 1.7 T&D rockers, 5/16 stainless valves, 7/16 double tapered pushrods, morel bushed lifters. Currently has stock cam journal and lifter size. I haven't seen any valvetrain issues but it is getting a new cam at this time and wondered if it would be worth the extra cost.

[swampbuggy]

Which block are you using ?

[Alaskaracer]

YES!! Stronger cam core for one. Biggest benefit is lobe designs. 55mm cams can use lobes that are easier on the valve train yet more aggressive than other lobes. Go with at least .903” lifters though, to take advantage of the bigger wheel.

[Racing68]

Dart Big M block. I knew the core itself would be stronger but didn't realize the lobes would be easier on the valvetrain. Is it a necessity to go to the .903 lifter, i know it's stronger but trying to tell him to replace an 800 dollar set of lifters that has 8 pulls on it with a 1000 dollar set might be a hard sell.

[CamKing]

55mm cams can use lobes that are easier on the valve train yet more aggressive than other lobes.

It's more of an "or" then an "and".
Going to 55mm will allow you to go with a cam profile that is easier on the valvetrain, OR more aggressive.
The only reason it's easier on the valvetrain is, that larger base circle allows for less side-loading on the lifter for a given lift rate. If you increase that lift rate when you go to the 55mm, you increase the side-loading of the lifter, and lose that safety advantage.

[CamKing]

Is it a necessity to go to the .903 lifter,

In most cases, no, but It depends on the cam.
How much lift are you planning on running ?
What RPM do you want to turn?

[swampbuggy]

Racing68 It would not make a whole lot of sense to upgrade the camshaft without going to larger lifters, .903 or .937". Mark H.

[Racing68]

Currently running .801 int and .790 ex but i don't remember the duration. I'll have to check the new pistons to see what the pocket depth is vs the old ones. RPM will be about 7800. I know it wouldn't make much sense to not upgrade the lifter but i have not figured a way to make customers pay more than they want to. I always push the more durable parts but some guys just don't have the budget.

[CamKing]

Currently running .801 int and .790 ex but i don't remember the duration. I'll have to check the new pistons to see what the pocket depth is vs the old ones. RPM will be about 7800. I know it wouldn't make much sense to not upgrade the lifter but i have not figured a way to make customers pay more than they want to. I always push the more durable parts but some guys just don't have the budget.

With lift in that range, and RPM, you don't need to go to .904" lifters.
If you don't want to go with more valve lift, you don't need to go to 55mm either.
If you want to go up in lift, then you should go to 55mm.