What seems to be the general rule of thumb regarding marine BBC 4 bolt mains regarding bolts vs Studs? Asking as I'm building around a 600hp motor with forged parts and have been told arp bolts are more than adequate.

The bolts will be fine. Unless of course, you upgrade to some Rect port heads

BAHAHAHA touché sir!

Don't forget to check the line hone

Yes I definitely will be double checking everything. Think I'm just in the overbuild mindset with head studs and mains when they are really not needed whatsoever in this kind of application.

Do you know if the ARP 135-5201 fit a gen V with factory windage tray?

no go with the stock windage tray. You'll need these from GM.

http://www.summitracing.com/parts/NAL-10224104/

I'd have no worries using the GM fasteners with a 4 bolt main block at 600HP, especially in a low rpm marine engine. If you told me you were building a 7000RPM deal, that's different. Overall, im not a fan of the Gen V blocks, but that's irrelevant.

Thanks! Yeah I've considered looking for a gen VI 454 block and have heard they match better to a gen 4 style head like my DARTS. But can't seem to find many and the ones I do stumble on people want big $$$ for them.

What's wrong with the Gen V? All are 4 bolt blocks (unlike the mark IV that are 2 and 4 and the 4 bolts are getting harder and harder to find), better oil system then the mark IV, 1 piece crank seal. I think the reason they got a bad wrap was because of the no fuel pump boss and non-adjustable rockers but they are easy fixes for anyone building a motor.
When you just compare then Gen V to the Mark IV (and not what they should have done ie, roller rockers and fuel pump boss like the gen VI and leave out the Gen V it was behind its time) its as good if not a better motor then the Mark IV. I'll take one any day.

the only time I use studs is when I cannot find a 4bolt main block.bolts should be fine