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Maybe some input from you seasoned guys regarding motor

Old 04-09-2015, 08:40 PM
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Default Maybe some input from you seasoned guys regarding motor

Ok, so I'm FINALLY getting around to getting my checkmate back together and ready for the water, but to be perfectly honest, I am not only a complete boat newbie but also a big thumping v8 newbie as well too (I always built sport compacts and imports, lil turbo monsters north of 600hp and strung out like a highwire across the grand canyon)

So I'm hoping you guys don't mind schooling a youngin, and help me out with some of this stuff. I've tried to research as much as I could, but there is so much information and most of it regards cars that I figured a post on here might be better.

As for the engine
Was a gen VI 502 magnum, spun rod bearings so I decided since I got this boat for so cheap I would go ahead and put some money into the engine and interior and finish updating the looks of the boat.

Started off boring the block to 4.500 bore, and installed an eagle stroker kit in it to bring it up to 540ci. I've since contacted Bob at Marine Kinetics and am just waiting on my invoices to be sent over for a customer hydraulic roller cam, new scorpion rockers, lifters, push rods, afr 325cc heads with some work done to them, arp head studs and cometic gaskets. I think I'm pretty good on the longblock itself, my other questions are going to be the rest of the setup.

Exhaust: Currently I have the hp500 manifolds (the gil marine, hardin marine, whatever company you want to say is making them) and what I guess are considered semi-dry tails. (they're the longer risers that end up just before the transom where they mix there). I'd love to put some afr monitoring on this engine for tuning and alarms. Bob indicated these manifolds are known for reversion, so would much prefer a dry exhaust (which is also better for me with o2 sensors) so we can open this engine up as much as possible. I realize headers are a much better option, but they're out of budget right now with everything else I have to get. Do any companies modify existing tails/risers to make them dry and through transom with extensions, and also have the ability to add in o2 sensors? and does anybody know if those tails are 316L stainless? Also do I need specific rings or something for the exhaust to come through the transom, or are they kind of just like cosmetic sealing rings? Last thing I want to do is set the ass of my boat on fire

Cooling system: Boat was raw water cooled, will need new impeller/housing regardless. Is the hardin marine stainless rebuilt kit (where it's just the housing) a good option or just stick with the regular plastic housing and rubber impeller? Also, I've been looking at crossover pipe systems that replace water circulation pump for the engine. Any advantages one way or the other? Does the crossover just eliminate one more potential failure or does it create others of it's own?

Intake manifold: Bob and everything I've read suggest a 454-r (edelbrock victor with the 4500 flange). I currently have an 850 holley, but was informed that anything shy of a 1050 dominator will be choking this engine, but can be ran to start with if I don't have one right away. Anything else to consider on this or is that pretty cut and dry?

Hope I don't become a pain in the ass with all the questions Generally speaking it's pretty easy to find info when you're working on something with a smaller pool of info, but the amount of info floating around for chevy big blocks is astounding, so I hope you guys can get me in the right direction.

lets make her run again!

Last edited by Kyain; 04-09-2015 at 08:43 PM.
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Old 04-09-2015, 09:05 PM
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I can tell you that the head studs will hit those manifolds, not by much, but enough that they won't fit. There are a few versions of the tails, the latest ones had a bigger hump to help fight reversion. You can buy dry tails for this manifolds, I believe Hardin has them, they are not cheap. I have the same manifolds and added an O2 sensor by using a hole saw to cut the outer pipe at 2" then put 2" OD stainless pipe in and tigged it to seal the water jacket. Welded the bung to the inner.
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Old 04-09-2015, 09:10 PM
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Old 04-09-2015, 09:13 PM
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hhmm, I never contemplated that the studs may hit the manifolds but not bolts.. Is it a situation that you need a slightly shorter stud on the outside rows. I much prefer studs over bolts any day of the week, but if I have to just go with the arp head bolts then so be it.

Also in regards to the exhaust... the original gil manifolds had leaks, so I got a newer set of the hp500 manifolds, but my tails are still the gil marine tails. I'm assuming they wouldn't have the higher hump you're talking about if they were manufactured by gil marine.

I have very little info on this boat and what it had going for it, was a divorce sale and the wife got it to sell, so I apologize if I don't have answers on alot of it lol

Last edited by Kyain; 04-09-2015 at 09:15 PM.
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Old 04-09-2015, 09:19 PM
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If your particular situation involves shorter than average no wake zones dis-interest in showing off the rumpity rump cam past the local watering hole ect ect one option to explore is fine tuning where the water comes out of a 540 cubic inch motor at potentially limited times of idling . A bjg motor dumps big water . Even idling .
If your that guy dumping the extra outlet water may be a easy way to solve your problem
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Old 04-09-2015, 09:29 PM
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The studs barely protrude past the nut, but the added washer under the nut seals the deal. Some guys put studs everywhere but the outer row, others ditch the washer and cut the studs flush with the nut once torqued. I'm not sure of the drawbacks of doing either one.
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Old 04-09-2015, 09:50 PM
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i have had to use bolts on the 4 lower boltholes,not a problem if you use good quality arp bolts.this happens with gm or edelbrock heads with exhaust ports that are not raised.
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Old 04-09-2015, 10:36 PM
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x 2 . I used Gills with Canfield heads and studs. No issues. Canfields are raised over .600". The AFR's are raised over .300" .
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Old 04-09-2015, 11:00 PM
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http://www.airflowresearch.com/index.php?cPath=68_72

I believe those are the heads that are being worked up for me. I'll have to verify with Bob tomorrow.

They indicate the exhaust port is raised .375"

They also indicate 1" longer head bolts needed on four bottom exhaust bolt holes?
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Old 04-10-2015, 04:35 AM
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Listen to what Bob says and you'll be fine.
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