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wakeskater
12-07-2006, 07:06 AM
"Hi from Australia. We have an Indmar 350 in our Lewis, its apparently 260HP and the valve cover bolts are in the centre of the heads and I guess that means they're vortec? We want to know if we can buy a GM 290HP 4 bolt 350cuid crate motor and still fit all the Indmar ancillaries (intake, water pumps, velvet drive etc) with no problems, ie a straight forward re-power? Also we want to fit a heat exchanger, would this kit 'SK4068F' from manifold wearhouse do the trick? Thanks for any help.
Ryan"

jimn
12-07-2006, 08:03 AM
"It is Vortec and another way to tell is if the intake manifold bolts are installed plumb (but parallel) to the centerline of the motor instead of perpendicular to the mating surface on the heads. Look for the block casting numbers, sometimes found under the valve covers or on the smooth surfaces of the heads or block. You should be able to get them form Indmar by e-mailing their technical department and telling them your motor serial number.

What happened to the original motor- overheat?

If the exchanger is made for a Chevy small block, it should fit but once you get the info from Indmar, I would ask Manifold Warehouse- they will know if ano other brackets will be needed. What year is the motor from? I assume it has a carburetor since the injected Indmar 350 would be at least 275 HP (from '93-'95) and 310-340 HP ('96-present), depending on whether it was TBI or multi-port."

bondo
12-07-2006, 12:51 PM
"Not to be Rude,...... But that Could be a Pre-Vortec motor,.........

The Change in the # of Valve Cover Bolts(ei;Center-bolt) happened Several Years Before the Vortecs were Intro'd in 1996.........
And,....
The Angle of the Intake Bolts were Also changed Before the Vortecs came into being......
I believe it happened with the change to Center-bolt Valve Covers........
The Intake Bolt Pattern changed by the Deletion of the 4 bolts in the Center Area of the Intake Manifold......As in, It's held in place by 12 bolts, at the Corners,+ None beside the Plenum.........
And,.....
SBC casting #s are on the Top Rear surface, Just Behind the Port-side Head,.... Near the Bellhousing junction......

Again,... Not trying to be Rude,......
I used to wander over here quite often,.... But after a couple of harddrive Crashs,... I lost my favorites,+ All.....
I'm still trying to get signed in,.... Nice to be Back......"

bondo
12-07-2006, 12:57 PM
"Ooooopps,.....

"The Intake Bolt Pattern changed by the Deletion of the 4 bolts in the Center Area of the Intake Manifold......As in, It's held in place by 12 bolts, at the Corners,+ None beside the Plenum........."


That Should read 8 Bolts,.... 2 on each Corner..... For the Vortecs.....

It's 12 bolts for All the heads previous to the Vortecs.....Just the Angle was Changed......"

jimn
12-07-2006, 01:26 PM
"None of the Indmar motors with Vortec heads that I worked on had the intake bolts perpendicular to the mating surfaces and the GM Indmar motors I dealt with (all from '93 and later) have the center bolt but the metal valve covers get the hex bolts and the plastic covers have the wide headed Torx bolt with the taper at the seat of the thread. Mercruiser, Yamaha, V-P and OMC used the metal covers on Vortec motors.

On cars and trucks what you posted is true but boats aren't as current in their technology.

Thanks for the casting number location. I have been asked for numbers from heads, too.

Actually, come to think of it, I seem to remember the 5.7L carb'd motor being about 260HP with Vortec heads. I worked for a MasterCraft dealer and MC stopped using carbs completely in '94 but I didn't start until about '96. Anything that was pre-'94 was either late '93 transitions models with EFI (LT-1) or older with 351 or 454.


"I didn't come here for an argument""

wakeskater
12-07-2006, 04:40 PM
"Hi thanks for the replies. It's carburetted and it is still running, just a little tired. Do you know any low budget mods to give these a bit more grunt say 300HP? We don't know whether to invest in new block + heads and start from scratch with a heat exchanger or reco what we have? Do the indmar motors have some special coating on them or is it just enamel?
Thanks again
PS I will email Indmar when I get the S/N off the motor"

bondo
12-08-2006, 10:34 AM
""I didn't come here for an argument"
Me Neither,......I'm just trying to spread Correct Info...

I'm just trying to explain that the Vortec Heads,.... Don't have the 4 bolts in the Center Area of the Intake Manifold,......
It's got Nothing to do with the Valve Covers,.... Period......

There were motors with the "Vortec" Tag on them, that are Actually Pre-Vortec Heads......
The Vortec Heads were Not Intro'ed til 1996,.....
EVERYTHING prior to 1996 are Not the "Vortec, Fast-Burn Chambered Heads".........
And,.... The Only Way to tell Which Heads are on the motor is to Count the Intake Bolts,......
12 Bolts is Pre-Vortec,..... 8 Bolts is Vortec.....

"I have been asked for numbers from heads, too."

Chevy Head Casting #s are cast into the Top of the Head,.. Under the Valve Covers......
Currently there are only 2 Vortec casting #s,....XXX906s,+ XXX669s....
The 906s are a Slighty Heavier casting for Trucks with a Heavy Duty Exhaust Valve Seat.....
The 669s Don't have the over-sized Exhaust Seats,+ are the 1s the Hot-Rodders look for.....
The 906s are the Best 1s for Boat Motors......

Good Luck........"

jimn
12-08-2006, 10:52 AM
Apparently you missed the 'argument' comment from Monty Python.

bondo
12-09-2006, 10:41 AM
"Ayuh,......
There were Many skits I missed....."

wakeskater
02-06-2008, 05:31 AM
"Hi again.

It's been a while but here is 14 months labor and 9K. We ended up going with a crate 350 Chev 290HP as the old motor was totally stuffed upon inspection. We went the whole hog this time with a custom built copper heat exchanger with cast bronze ebds, aluminium manifolds, Edelbrock Performer Intake manifold, oversized Johnson F6-B9 sea water pump, 600 J series Holley, hi volume fuel pump, 316 stainless exhaust with Oxygen sensor ports etc! Since this photo I have added an expansion tank for the heat exchanger and an oil/air separator tank. We are just about ready to rock, turning the key next week, will be glad to be finished! We have done all the work ourselves bar the machining of some parts and the heat exchanger.
Ryanhttp://www.marineengine.com/discus/messages/3/146863.jpghehehehe

bondo
02-07-2008, 09:25 AM
"Ayuh,...... Looks Wicked Sweet,.....

Good Luck with the Shake-Down Cruise......http://www.marineengine.com/discus/clipart/wink.gif"

wakeskater
02-08-2008, 04:39 AM
"thanks mate http://www.marineengine.com/discus/clipart/thumbs_up.gif"