I'm happy with the plan to fix it. What is your opinion on lifter bore clearance on a marine engine. It is a Dart block.

.0018-.0020, no more than .0020. Depending on the lifters, you'll want to measure every one. I would recommend Morel lifters as they seem to hold the best tolerances and run on the large side compared to most others.

Had same problem on 540s, wound up being lifter only had .0005 clearance . Thought it was guide clearance. Dart lifter bores are on the low side of the tolerance and lifters must be fit by brand as sizes differ .

My dart block with morel lifters is now .0017 no more problems. Runs 43 -5300 rpm for 70 m:)iles. Makes 680 /680 4700/5600.

Still wanna know can and dyno sheet for a 680 hp claim at only 5600

Sorry we put comp short travel lifters in. I have one that is 670 at 5600 then I put flame arestor on and it went to 680 previously with tight lifters this motor only made 550 at 5600. These motors I built with dart iron eagle 320s .

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Ill look for the final sheet with the 680 . I made like 10 pulls on the motors. Cam is small ill find you the card . Comp 9.6:1 115 cc no porting just bowl blend after hand fit on the valves .

Well picked up my engine yesterday. I have to give BES engines the thumps up. My cost zero$$$$.
Thanks Tony Bischoff and staff I will be back with all of my engine needs.

Good to hear!!