View Full Version : 350 Mag Questions

06-11-2011, 01:03 PM
Replacing / rebuilding a '87 Mag 350 (in a '87 Z21) and looking for some input

1. 2 bolt vs 4 bolt mains
2. Vortex heads vs Original (realize intake replacement is required)
3. Roller Cam vs Flat Tappet
4. Distributor - Original vs Performance After Market (i.e.: Mallory) In the process of rebuilding engine and wire lug rusted / broke off.

Also, looking to replace oil pan with one with greater capacity. Engine already out of boat and was wondering if anyone that has a like boat can measure how much room under pan and how much more forward and sideways the sump can be.

Thanks all.....

joseph m. hahnl
06-11-2011, 07:59 PM
You Need Roller Cam and Lifters to be Hi Performance, especially in marine engines. Open that Mag up and you'll see roller tappets.

Don't bother with the old school heads, if your buying new, go Vortec all the way. If you go short Block You Can By a Horse Power top end kit from Summit. Just use a Marine cam.

4 bolt main will Give you way more HP potential.,But Being an 87 it's has Alpha 1 which the gears have a horse power Rating, that is well under what you can get out of a 350.