Posted by PARTSMASTER on December 30, 1998 at 22:52:31:
In Reply to: Thanks for the info, PARTSMASTER posted by Steve M. on December 30, 1998 at 14:41:02:
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: : : I've got a Gen VI 454 (casting# 10237297), with a set of casting# 10114156 heads(round port, 2.07/1.72 valves, the same heads as the 502 "Tow Truck" engine)in my Jet Boat. First, can anyone tell whether this is a 4 bolt block or not? Second, is there any performance potential in these heads, or should I just give up and buy some high-po heads? The desired max rpm is 5000-5200. It's got a 750 Holley, and factory cast iron low rise intake. What is the best intake to use, based on the round intake ports, and are there any recommended cams for this combo. I haven't been able to find much info. on this engine, but I know that someone here has the knowledge.
: : This is a 4 bolt main block. The heads are low performance heads made for low speed RPM and torque. Ths engine can be upgraded in many ways heads ,intake , camshaft, Don't forget it must fit what you want your boat to perform at.Your exhaust is a factor also.Is the boat a closed or open cooling system.
: Thanks, partsmaster. The boat runs an Indmar water cooled exhaust (thru-transom), and is a straight through cooling system (no water pump), and just uses the water take-off from the jet drive to cool the exhaust and engine. The boat itself is a low-profile performance style tunnel hull, 19 feet long. It is used primarily for skiing and family style running around, but I love the top speed runs also. The boat will currently run about 65 mph.
: I was mainly thinking of trying to optimize the combo without changing heads at this point. Will these heads show any benefit with a "bigger" cam, and the required adjustable rocker setup, and an aftermarket intake, or is the flow limited by the ports and small valves? If these heads will suport more power, I'll do it, but if I'm just wasting time and money, I'll save my $$$ for new heads, intake and cam in combination. Thanks again Partsmater, and Happy Holidays.
Save your money for a new set of heads .