I'm rebuilding my 468 rite now. I went over kill on the pluming when I rigged it. The motor never got over 135% I know this is bad. never had a oil temp gauge witch I know was too cold also, or a vacuum one either. I will before it hits the water again. Here's my Questions

 1. what is the prime water temps for a bbc while on the throttle and idle?

 2. What is the prime oil temps for a bbc while on the throttle and idle ?

 3. What is the prime motor vacuum for a bbc while on the throttle and idle?

My Motor.
Its a 468 bbc mark 4, 4 bolt mains, steel crank, h-beam rods, forged probe pistons, were 12-1 compression but am cutting them and running a thicker head gasket to run pump gas. want it at 10-1 or 10-1/2-1, total seal rings,fully studded block, RHS pro topline alum heads, 360 cc plus full race port & bowl work, 750 lift custom grind cam (solid roller), Jessel shaft mount roller rockers, beefy push rods & guides, howards solid roller lifters, weind high ram tunnel ram match ported to heads an machined & welded for 72 lb injectors (bosch), top machined off and welded a blower plate so I could mount the blower spacer with threaded holes for the 300 shot of nitrous and a bird catcher/ (throttle body) on top of that. Its a FAST XFI EFI ECU. aremotive vacuum pump. Harden marine's 3" Polished Stainless Oil Cooler with Exclusive Cupronickel Core, fast duel sinc dizzy, MSD 7al box, MSD hvac 2 coil Big wires with insolaters (sp). aremotive fuel pump, 100 micron filter and a water fuel seperater. ( good up to 1200 hp efi)

Before the rebuild it did 760-780 hp on the dyno and just a tad under a 1000 hp with the 300 shot. 6,500-7,200 was its peak rpm range but was still making good power up into 8000 rpm ( didn't want to push it further than that, no need). To compensate for the power loss from decreasing the compression to run pump gas I'm going from a 750 lift cam to a nasty 850 lift cam. I hope I don't lose any hp.

I went through extensive time and effort to rig my boat and apparently I did too good of a job with it.lol

 4. my last question. when I pulled the motor I had a tone of sand and dirt in the block. I was running hardin marines fancy dancy $ea-$trainer but the wholes in the screen are to big to filter fine stuff like dirt. What options do I have to filter the sand and dirt from getting in the block. I was thinking of making a new screen for the current strainer with smaller whole's but don't think that will work. Your ideas would be greatly appreciated Thanks, Jimmy.

As far as sand in the block... try plumbing your water in through the small holes near the pan. This will not allow sand to settle in the block. I am plumbing mine this way right now. Plumbed the standard way your block theoretically can fill with sand up to the water pump inlets.

As far as sand in the block... try plumbing your water in through the small holes near the pan. This will not allow sand to settle in the block. I am plumbing mine this way right now. Plumbed the standard way your block theoretically can fill with sand up to the water pump inlets.

This does work very well...Also makes temperatures more even from cylinder to cylinder...

GT