29 Scarab with twin 350/300hp Magnums. I'm having a problem getting over 4800rpm. If I trim the drives to pick up the lost R's I loose speed?

I'm stuck at 66.50mph - I did hit 70.03 @ 5100/52rpm but that was only once and I have yet to do it again

I may be wrong but I think anything over 5000 rpms is to much for a 350. Even 5000 rpm might be to much for a 350. For a 502 5000 rpm is fine but I thought I read some where a 350 should run at about 4800 max rpm.

Wellcraft said 5150 rpm is perfect - (Those little chevy's spin like 2-strokes)

I just looked it up in my manual and the max rpm for the 350/300 is 5000 rpm. If you are spinning it over that I would be careful of valve float and springs. The actual rpm range is 4600-5000.

John S.

Carb mags , 46-4800. Mag mpi's 5000. 66.5 mph is all we get! Running 23 mirage + W/mpi mags. Mag mpi's are rev limited I believe. Try running with the tide and you may break 70 again!

My one 70.01 run was down river, wind at my back with a light load of fuel and light wife ...

But I'm still missing 200rpm ?? That could be another 1.5mph

Off to the prop shop

Sounds to me like it's running good. Fill it up , go out for a ride and have fun. Don't leave it pegged at the max for too long or you'll be replacing those motors sooner than you need to!

Small blocks like to rev to about 5200. -- They just sound happiest there.

Skip it, I just looked at my Gas Receipts from the weekend 3000rpm works best for me now.....

LMAO