1987 21 ft scarab1 perf questions 350 mag

johnlx302 · 11-03-2009, 12:21 PM

hey guys just wondering what you 350 mag owners do for some added performance. it went strong all summer long at 54-55 on gps with a 2yr old long block and a 21p mirage plus prop. but i just tore down the motor for a long winter overhaul. block is .040 over 1987-1995 block and the heads are 1987 and up center bolts (nothing fancy). just wondering what perf mods work on a marine setup heads intake cam etc... looking to squeeze a few mph on a budget. also the boat has threw hull with stock manifolds. any suggestions woul be helpful on which route i will go.

KSims1868 · 11-03-2009, 12:40 PM

I had a 23p on my 1989 Scarab Excel. It was basically (I think) the exact same boat you have. I was able to get up to 65 mph and cruise at 50-55 all day long with the 23p prop.
The prop made a HUGE difference. I used a Lazer II vented prop (23p) and it was a heck of an upgrade. Worth every $$.

My 350 had an upgraded cam, carb, and intake. Nothing radical...mild performance upgrades. The engine had about 300-320 hours on it and at least 2 seasons on these upgrades. Just like you...I had stock manifolds with thru-hull pipes...again nothing fancy.

johnlx302 · 11-03-2009, 12:50 PM

thanks a bunch for the info do u remember what cam you were running i dont want to over cam the thing and suck water lol

KSims1868 · 11-03-2009, 04:27 PM

No I don't. I didn't install.

johnlx302 · 11-04-2009, 06:38 PM

ok just checking thanks though