need advice on what to do for the rest of the season with my motor.
 

I have a 1997 scarab 22 with the 330 HP 454 merc I don't think the motor has ever been freshened up and has been used heavily . I have been having a lot of problems getting the boat on plane. I even just stepped my prop down to a 21p mirage and with 4 normal sized people in it it takes 1-2 min just to get on plane. So I checked compression and on the number 3,4, and 6 cylinder I'm at 95psi and all the other cylinders I'm at 112-115 psi. I put oil in the cylinders and checked compression again and no change still 95psi. I will be freshining up the motor this winter doing the 496 stroker kit, cam, the 078 heads or Afr heads,intake and Carb.
Here is my question since I'm leaning that the heads are the problem not holding compression, do I
A-take the heads off and get them checked and fixed for the remaining season I know their the peanut port heads and worthless.
B- buy a better set of heads now and slap those babies on. The part I'm worried about is if the bottom end will hold up to a better set of heads.
Any info and insight you could give me would bee great. I can't just go out and spend 9000 on new drop in or anything just good advice would really help.

Put the heads on and baby it... You could get lucky and find a used set like you already have also, until this winter

Baby it? That's not in my vocabulary:-) I just don't want to cause catastrophic damage to the motor. I will only be taking the boat out 4 -6 more times. If I did go with different heads should I buy afr or the 078 OEM heads or some other heads?

Maybe pull the heads do a quick valve job then do them right in the winter.

fixx
 

what state do you live in? i have a gen6 30 over reman short block,,was a salt water engine but its new..has a little surface rust on it but ill let it go for 900 bucks..find a set of vortec bbc heads and slap them on and your assorys and go boating..

Just spend the money on better heads now, don't rebuild the peanuts. You can use the new heads later when you build a better engine. I got good heads on my merc 330 bottom end, good heads wont stress the engine. Spinning too many RPM's will stress the bottom end.

If I change the heads will it raise my compression and will that stress the bottom end I just don't want to break a rod. I'm not going to try and spin over 4900. I am OK with getting some new heads that is just less to get this winter. What heads should I go with that will in the end work great with the 496?

I live in Denver. I don't really think a short block is where I want to go at this point in Time. Thank you though.

Ok so i did a little research and the heads i have have 118cc chambers. Some of the after market heads come with 118 and 119cc chambers. I will not change my compression at all (minus the bad cylinders). So what kind of heads do i need. This is a fresh water boat and i do like to run it. I didn't know if there is a difference between auto heads and marine heads. I was gandering at some world products cast iron heads Cylinder Head, Merlin, Cast Iron, Assembled, 119cc Chamber, 320cc Intake Runner, Chevy, Big Block, or the edelbrock marine BB-Chevy Performer RPM 454-R Marine Aluminum Cylinder Head
315cc/300cc (Long/Short) Rectangle Ports 118cc Comb. Chambers 2.250''/1.890'' Valves
7/16'' Rocker Studs? Should i stick with rectangle or oval ports? Keep in mind i will be doing the 489/496 stroker kit and the rest now. Im not opposed to getting a intake and carb right now as well. Heck ill have most of the top end done. I really want the lost power back from loosing the compression in the 3 cylinders right now not looking to make a ton of extra power. if i could be at 330hp+ again ill be happy untill the rebuild this winter

put an ad in swap shop, wtb rect port heads or whole bad 454 mag motor. compression loss is valves, you already know that. i had 2 330's in a 30 IMP with 1000 hours on them. that bottom end may be healthier than you think. mag heads and intake, or any aftermarket rect port dual plane with those heads will prolly give you 340-350 with the stock cam. then, who knows? you might find yourself punching a hole in the bulkhead behind the back seat and threading a better cam in there? oil pressure gone down any noticable amount the last few years?

No oil pressure loss still 60 at idle. Thanks for the info dereknkathy!!! I am probably going to go brand new heads complete and shipped right to my door before this weekend.
Well folks I just removed the heads!!!!:evilb:
The cylinder walls look great!!! I am going to probably go with the oval port heads because the exhaust manifolds are oval. So What New Aftermarkets should i buy and the other thing im wondering about is the rockers are the torq down NOT adjustable. Can i reuse those rockers and torq them suckers down. OH yeah im going to be buying a intake and carb as well air gap and holley