jmherbert

I am wondering what jets you all recommend for my combo;

388ci SBC
Crane 100072 (284H, 228@050, 112LSA .512 lifit w/1.6 rockers)
Rhodes lifters
Dart Iron Eagle platnum 200cc 72cc chambers, angle plug
MSD RTR distributor (mechanical advance only) set at 7degrees initial, 32 fully advanced, full advance comes in around 4000RPM
Flat tops give around 10.5:1 (I know, its higher than I like or planned)
Brodix HP1 dual plane intake (similar to RPM performer)
Revolution exhaust.
Holley 4150

I have already put 72's in front and 74's in back. It ran decent with these, but I had a cooling problem develop after a short run. Pulled plugs and #3 and 7 were burnt up, but all other 6 looked good. I had absolutely no signs of detonation. Put replacements in, and they held up fine, but took it very easy back to the dock. Was running AC43's, going to try 41's or 42's next. I am also thinking I should try maybe 75's in front and 78's in back.

Still haven't nailed down the cooling problem, changed impellor, and found old one was 100% perfect. Replaced anyhow. Pulled hoses while in neutral, and looks like it flows good. I have the 4 hose alpha setup (2 hoses to each manifold) I took the 'guts' out of the thermostat, and it still goes above 160 with the boat in the water (on the trailer) and no load.

I realize this motor might be too much for the stock alpha water pump, but I don't think it should heat up like that with no load and somewhat unrestricted water flow.

I really apprieciate any advice on any of these issues!

Island Time

May be a silly question on the temp issue, did you check the sending unit and Gage for accuracy?

Badtoon

Get in touch with Nickeson Performance and have them build you a carb for your Engine. They have there act together big time. Save some pistons, valves ETC.

jmherbert

No, but it is indeed overheating. Got the nasty dieseling effect. Got carb and timing dialed in, and in the short runs (30 seconds to 1 minute) to do it the motor did not overheat, but got up around 180 degrees. Plenty of water is coming out of the tips, and at RPM's above 2000 the manifolds/risers are cool to the touch. As engine temps rise, the manifolds get cooler. It is like the circulating pump is not working.

Oh, yeah. Circulating pump is brand new mercruiser. I have never heard of one not pumping. Heard of them leaking and cracking during winter, but never not pumping. Not saying its impossible, cause thats what my signs point to. Little or no pressure is felt at the circulating hose, not even close to a top hose on a car/truck when the tstat opens.

10x

Sometimes when you burn up an impeller(possibly from the previous owner) the little pieces of the impeller get caught in the coolers reducing water flow. Just a thought, but I'd try disconnecting the hoses going to the oil coolers and back flushing them. I've seen these things get clogged with little pieces of impeller.

Or, possibly if you're running oil temp thermoststs, maybe they're not opening when they get to temp. I had this problem last spring. Oil temp kept climbing as I was driving. Finally I pulled the thermoststs out of the housings, and put them into boiling water to find out that my 210 degree stats, did'nt open till around 255-260 temp.