I think your short on your 500hp goal with the stock manifolds. I have basically the same engine but a 468 and not a 496 and a smaller cam Iskey 270/280 mega and 1.7 roller rockers, I went with that cam due to having stock manifolds and not wanting to have reversion problems. I was looking for 450hp on the dyno when I built my engine. My engine made 407hp/460 torque on the dyno with headers but I bet it only makes 365hp in the boat with accessories and stock manifolds.

Lots of people estimate what their engine build will make but not many pay the money to dyno the engine. I payed for the dyno to make sure my engine was broken in and tuned properly but I also wanted to know how good my build was.

Get some good exhaust and let that engine breath!

Might pull the engine this winter and have it put on the dyno. Going to see what happens with the jetting and timing. It it helps it will only be a bonus when I get my new exhaust.

Weather is going to be great here today. Just about 65 degrees. Going to see what happens with timing and jetting.

Ran the boat. Timing helped a bit. The water was dead calm with current. Not good for going fast. Hit 60 AGAIN!!!!! :lolhit: Pulled plugs looked lean/ even with 83/90. Ran best with 83/85 with 36 deg total. In 1 footers I figure 64/65. Same as before. Taking the carb to Nickerson Performance in Bristol, Pa tomorrow. Talked to him about the issues and said he can make it better. We will see. Did a static chk on the cyl. All are between 170 and 180 psi. At least nothing is hurt there.

You need to tune jetting with a air/fuel gauge ... thats the best way . Reading the plugs with the new fuels is tough. Your going to have to install a o2 bung before the water in your exhaust system. If you decide to dyno the engine give Tim Jepp a call @ 856-589-5658 ... he has tuned my last 6 engine builds and is local NJ . In my opinion your engine is down on power . My last n/a 496 made 606 hp @ 5700 ... 731 hyd roller installed @ 107 ... oval port 290 edelbrock heads ... rpm airgap intake . 9.6 to 1 compression and a custom 1030 cfm 4150 carb built and tuned by Tim . The key is in the tune and I have found dyno time to be well worth the money and time invested .

Took the carb to Nickerson's today. Great guy! They request you bring a completed engine and boat spec sheet from their web site prior to going. Dean (owner) took time to talk with me about my issues with the boat. I took my spark plugs with me and that helped. My carb HAS ISSUES! Going to swap out my stamped rockers for rollers and put the carb back on next week. Hope to see an improvment.
Thanks Jetmech for the heads up on Tim Jepp. I'll call him.

You need a new intake. The factory intake is all done at 500 hp power level. Look for a Mercury 500 style intake. Factory heads are hurting you too.

Wannabe

Ditto what JM said. That exhaust though will totally kill your scavenging which is necessary n/a and with rect port heads. Pretty much any aftermarket manifold would be an improvement with a full length header like an eickert getting you the real pop.

BT

Pulling the engine this week to take it to be put on the dyno. I will be able to be there and work on my engine along side Dean Nickerson. This should be fun!!!!!!! Keep you guys posted......

Carb is done. Picking it up tomorrow. Friday weather looks good. Going to go for a spin and see what the carb upgrade does. Watch me go slower..........:lolhit:

Pull the engine next week and dyno it, also going to install a set of 1.8 roller rockers