Rebuilt Engine Install

[Wild Horses]

Installing a rebuilt engine in my buddies boat (he winter cracked the block)
It's a Gen V 4 bolt main, 454, bored 30 over, 9.5 to 1 comp,
large oval port heads,
Edelbrock Performer Intake,
New Sea Demon 750 Mechanical Secondaries,
Comp Cam: Lift In. 544 Ex. 547 Duration In. 270 Ex. 286
Lobe sep. 112
The rest is basically stock Merc
Couple of questions
1) What kind of spark plug and heat range would be suggested.
2) What kind of H.P. would this motor make.
3) Oil recommendations for breakin.
4) Timing total advance.
We are at 5200 ft above sea level.
Any suggestions are great.
Thanks
Clint

[Rexone]

So you engine gurus gonna help Clint out? I'm sure he doesn't want my marginal engine advice...

[1BIGJIM]

I am no guru by any means but that is the exact combo I put together. I have a little hotter cam. I have talked to Dennis Moore several times about this engine and he has told me more than one time is should make an easy 420hp with plenty of torque. Nothing special compared to some of the engines you guys build. Enjoy your new engine.

[DaveA]

I don't know about the Sea Demon, but it might help if you called Barry Grant Carbs and discussed the carb's compatibility with that cam. Duration may be too exotic. Not sure, but it would be too much for the Speed Demon 750 mechanical according to my conversation with them. They say it would be tough to get it to idle without loading up with a cam over 240 @ .050". Don't know if the centerline has anything to do with it.
It may be worth a call if you guys haven't already.
DaveA

[victorfb]

i was thinking the same thing that DaveA said. even an 850 demon cannot handle that much duration on the cam. you may run into problems at that high altitude.

[Wild Horses]

OK, I called Barry Grant and found out that I need to go by the duration at .050 Which is In 226 Ex 236.
I was listing the duration at .006 tappet lift (I guess it is not the reading that you go by).
Got sent the wrong carb, they sent us a 750 Speed Demon instead of a 750 Sea Demon, Threw the old 750 holley back on and ran it, It still stumbles right off idle.:yuk:
Now with this new found wisdom and knowledge can anybody give me a hint as to?
1) total timing advance. (I set it at 32 degrees, 11 static)
2) recommended plugs and approximate heat range.
Clint

[blowngas]

I would run at least 34 deg total timing if not more----you did check and make sure the timing mark is zero at TDC right?----I like to run NGK plugs----easier to read due to cadium plating---check the tech thread above and find out which plug you need---heat range will probably be around a 6 or 7