Marinising 350 Chev

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mjleguay
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Marinising 350 Chev

Post by mjleguay » Fri Jun 25, 2010 3:37 pm

Hi guys,
I eventually made the decision to go with a V8 in the Audeen.....which means I had to go with a dog clutch so just have neutral and fwd....The problem I have now is about the plumbing situation.....Since my engine is now the other way round, ive installed a thermo blanking plate, since that's no longer at the top....I think I have to drill holes to allow for water outlet at the higher end of the heads. Just wandering if anyone has any experience with this that can help as to where to drill, etc?? Also, I picked up a second hand heat exchanger a couple of years ago and Im not sure if im able to run this with the engine going this way? It has a cylinder that can be mounted anywhere and a separate header tank that originally bolted on to where the thermo blanking plate now is?

I'm thinking I should of gone with the V6 and the Velvet drive! God I hate making decisions!

Thanks, Marcus

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Mr Hot Rod
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Re: Marinising 350 Chev

Post by Mr Hot Rod » Sat Jun 26, 2010 5:56 pm

mjleguay wrote:... I've installed a thermo blanking plate ...
Not familiar with this type of plate. Can you post a photo or two of your installation ??

Hopefully the following photos of Bruce Dow's flywheel forward Chris-Craft 283 might provide a clue as to where to drill the head for water outlets :
  • Image

    Image

    Image

    Image
Hope this helps !

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Paul Kane Chelsea, PQ

Building the Glen-L Hot Rod : http://www.boats.chelseacoachworks.com

Nova SS
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Re: Marinising 350 Chev

Post by Nova SS » Sat Jun 26, 2010 7:19 pm

Paul, does the larger of the two fitings contain a thermostat?

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Mr Hot Rod
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Re: Marinising 350 Chev

Post by Mr Hot Rod » Sat Jun 26, 2010 9:27 pm

Engine doesn't have a thermostat ... The water pump has a circuit for each cylinder bank (1 inlet and two outlets).

Image

Photos are from a future WebLetter article on rebuilding Bruce Dow's vintage 283. We'll have to finish up the article and submit it as soon as we get the Hot Rod back on the water !

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Paul Kane Chelsea, PQ

Building the Glen-L Hot Rod : http://www.boats.chelseacoachworks.com

Nova SS
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Re: Marinising 350 Chev

Post by Nova SS » Sat Jun 26, 2010 9:39 pm

The only reason I asked was in your first picture the fittings on the heads are two differrnt sizes and then in the close ups it sort of looked like a tstat would fit in the housing. Oh well thanks for the education :)

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Caber-Feidh
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Re: Marinising 350 Chev

Post by Caber-Feidh » Sat Jun 26, 2010 11:18 pm

Does your manifold have the rear coolant crossover? If it does, most of the time they are drilled, and tapped for 1/2" NPT. If not, unless you are somehow attached to the stock iron, an edelbrock air-gap performer (#7501 if I remember) with the rear water outlets tapped cures the problem.
Some plan to stroll through Saint Peter's Gates, I plan to go through them at 150mph... backwards... in a screaming ball of flame, with a glimmer belt wrapped around my head, and a NOx button in my hand.

Nova SS
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Re: Marinising 350 Chev

Post by Nova SS » Sun Jun 27, 2010 5:59 am

Good point Caber :)

mjleguay
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Re: Marinising 350 Chev

Post by mjleguay » Sun Jun 27, 2010 3:02 pm

Paul, thankyou for those photos, I appreciate you putting them up cause they're a great help. I've uploaded a photo to show the thermo blank....it just blocks off where the thermo housing/water outlet originally was.
Caber, I'm not sure if I have the crossover...are you able to tell from this photo?
IMG_2137.JPG

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Caber-Feidh
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Re: Marinising 350 Chev

Post by Caber-Feidh » Sun Jun 27, 2010 11:29 pm

Look at the left back side of the engine in the picture, you will see a NPT threaded pipe plug (usually 1/2" NPT, but There are some 3/8" on the mid 80's vintage 305's) That is a crossover tap. Check the other bank, there should be one there too. They will be on the distributor end of the motor, one on each bank. It appears that manifold doesn't have a heater tap in the front. It should have a crossover, and taps in the back... or it came from something with no heater. :shock:


Your manifold appears to be a later '70's low rise. Good match for the 487 casting heads it appears you have. (that was GM's best big-chamber head... before they decided to make the castings as thin as a tortilla chip) It's really not going to appreciate all that plenum volume you are adding with the wedge. low volume runners, and rough transitions will assure low velocity in a big volume plenum. Don't over-carb it, or it's going to be an enormous pig that dogs like crazy, or coughs and dies when you open the throttle too fast.

Here is a good image of an aluminum copy of the old GM high-rise "marine" manifold. (with some nice Nox bosses already for giggle gas)
Attachments
manifold.jpg
Some plan to stroll through Saint Peter's Gates, I plan to go through them at 150mph... backwards... in a screaming ball of flame, with a glimmer belt wrapped around my head, and a NOx button in my hand.

mjleguay
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Re: Marinising 350 Chev

Post by mjleguay » Mon Jun 28, 2010 11:04 pm

Ok....the manifold doesn't have any taps at the back or the rear crossover.....there is a tap just at the front left of my photo (plugged with a blue rag)....not sure if that's for a heater or a bypass of the thermostat for some reason????
Sounds like I need to get a bit more educated on this engine since I really know nothing about chevy's...the carb that it came with is a 650 Holley...so will this be "over carbing it"....I drove the engine in the original car before i bought it and it ran and accelerated beautifully....however that was in a car...
As for the carby wedge, I popped that in just to bring it back near level...but didnt think about the extra plenum space it was adding....are you suggesting not having a wedge at all?
Sorry for asking what could be basic questions....but I really appreciate the education!
Marcus

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Caber-Feidh
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Re: Marinising 350 Chev

Post by Caber-Feidh » Tue Jun 29, 2010 9:30 pm

I would seriously consider a manifold change. When the choices are machining the heads for outlets.... which will void the rebuild warranty (it looks like you have a rebuilt head warranty tag on the right bank) or change the intake. The intake would be allot easier to change than drilling heads for fittings. (not to mention intake gaskets are allot cheaper than new head gaskets)

My choice would be replacing the manifold with something like an Edelbrock Performer (not the RPM version) Be sure it is the tapped one. Block off the exhaust riser passage, and have a good reliable engine. If you don't want the manifold and riser to get that gruddy white oxide on them, shoot them with some rattle-can lacquer. Second choice would be junk-yard surfing for an intake with taps. Personally, I hate any work that involves the words "heads", or "head gasket", or "head bolt", and would rather change an intake while wearing snow-shoes on my hands and suspended from the garage roof from my toe nails, than pull a head for machining.

Big plenum with a 650 is going to be fine. .. Is it a double pumper? If you have a somewhat stock-ish cam, Jet at 68 primary, 77 secondary, 6.5 standard flow power valving for cruising, 5.5 high flow if I was planning to drive it like I stole it. Don't let anyone sucker you into a dual stage, they are a PITA, and never really seem to be all they are claimed to be. I am not a vacuum secondary fan, that ghost-ride feeling of the secondaries not closing instantly when the throttle is shut down scares me worse than a closet full of boogy-men..... on halloween... with a full moon.



A little OT, is this engine broken in? or is it a fresh rebuild with a new cam? THE quickest way to hose a SBC after a rebuild is to break it in at low speed. If it's a new cam, break it in before you put your drive line together. (Boat hardware doesn't like 2K+ running on dry land.) I use 7 qts Shell Rotella diesel oil (10-30) and one bottle of EOS additive. (in a 5 qt pan) Prime the system, start the engine, and get it to 2200 RPM immediately. Never let it fall below 2K-never-never-never. Keep an eye on the temp, if it's too cold, you can crash a valve (or 16). After 20 minutes dump the oil, and change to regular 10/40 dino oil and go for the initial voyage. (no synthetics for the first 80 hours or so, if some idiot honed the jugs too lightly, it isn't going to seat the rings with synthetic). It sounds insane, but the only real defect with the SBC engine is the lack of cam, wrist pin, and decent lower cylinder oiling. The over-filled case, and 2K RPM run-in assures the crank will be splashing away like a kiddy-pool full of kindergartners, and the pieces-parts get sufficient lubrication. Done right it's a 5500+ hour engine.
Some plan to stroll through Saint Peter's Gates, I plan to go through them at 150mph... backwards... in a screaming ball of flame, with a glimmer belt wrapped around my head, and a NOx button in my hand.

upspirate

Re: Marinising 350 Chev

Post by upspirate » Wed Jun 30, 2010 6:36 am

Is that a Holley carb designed for marine use? In a closed compartment,there is a difference.

Open, high mounted engines like Caber runs,and I used to, it wouldn't make a difference (well maybe not legal though)

Nova SS
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Re: Marinising 350 Chev

Post by Nova SS » Wed Jun 30, 2010 12:08 pm

Non Marine Carbs on a boat are NOT legal in Canada as I've recently found out. Thanks Paul (Mr Hot Rod) for the heads up. From what I've seen on the Vdrive site it appears they are ok in the USA if the motor is not in an enclosed space.

mjleguay
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Re: Marinising 350 Chev

Post by mjleguay » Wed Jun 30, 2010 4:15 pm

The engine was rebuilt two years ago and went into a 1960 Chev Belair which was hardly driven. The car was then bought by a guy who removed the engine (and sold it to me) and put a Gen 3 engine in it.....so i'm assuming it's been broken in.....but not had much use.
The 650 Holley is what was in the car....so no it's not a specific marine use one....does this pose problems?
Caber, thanks again for the detailed info. I think you're right with sourcing a new manifold.....seems a lot less hassle....

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tunahelper
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Re: Marinising 350 Chev

Post by tunahelper » Fri Jul 02, 2010 9:17 pm

mjleguay

I would like some info on your dog clutch set up. Pics would be cool also. I have a chain coupler now that is a PITA to work with.

I am running a four corner water outlet intake in my crackerbox and it works fine. Check out Professional Products intakes. I am using the Crosswinds intake on my sbc.

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