| Author |
Message |
    
mike weakley
Member
Username: mikey43
Post Number: 7
Registered: 10-2009
| | Posted on Friday, October 30, 2009 - 02:31 pm: | 
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hi everybody i have a 350 gm carbed motor in a 97 baja. fixin to have heads reworked any body have any good ideas? more power etc. |
Brian Brackett
Senior Member
Username: kainon
Post Number: 1013
Registered: 03-2009
| | Posted on Friday, October 30, 2009 - 04:44 pm: |
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good ideas? well you would see very little gains if any, and typically aren't worth doing by unless you are going to make other improvements. Cam, intake, 2bbl carb to 4bbl carb, different manifold.
What are you looking to get out of it ?
How big is the boat ? 21' ? 27' ?
You can have some porting and unshrouding done to the heads, get better valves, larger valves, goto a slightly higher rocker ratio 1.6 instead of 1.5.
But if you move more air, you'll move more fuel. IF you've got money to spend, drop in a bigger engine. |
Brian Brackett
Senior Member
Username: kainon
Post Number: 1014
Registered: 03-2009
| | Posted on Friday, October 30, 2009 - 04:45 pm: |
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ps.. you can get higher flowing heads off the shelf, but you'd need to change cam and maybe the intake to take advantage of them, then you may need to change the exhaust manifolds to match. |
mike weakley
Member
Username: mikey43
Post Number: 8
Registered: 10-2009
| | Posted on Friday, October 30, 2009 - 05:11 pm: |
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21' edelbrock 750 marine carb,4bbl alum holley intake,lunati cam.all of this installed before i bought the boat, that is all i know. thanks brian |
Bert Goodrich
Advanced Member
Username: bertg
Post Number: 293
Registered: 10-2006
| | Posted on Friday, October 30, 2009 - 05:54 pm: |
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mike weakley You could check and see if your 350 has the big valve heads. If not find a set, sodium cooled preferred, and have them reworked.
Bert |
makomark
Senior Member
Username: makomark
Post Number: 1803
Registered: 09-2008
| | Posted on Saturday, October 31, 2009 - 12:39 pm: |
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I'd suggest you measure the cam and call lunati and see what they recommend for the heads. No sense in putting money into mods is the cam won't let you use them.
Beyond that, good guides and adequate springs are all I'd add to a good valve job. |
mike weakley
Member
Username: mikey43
Post Number: 9
Registered: 10-2009
| | Posted on Saturday, October 31, 2009 - 01:59 pm: |
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thanks men good info!!! new at this |
GJack
Member
Username: gjack
Post Number: 12
Registered: 10-2009
| | Posted on Saturday, October 31, 2009 - 11:12 pm: |
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Mike: GM Performance Parts has a nice set of aluminum heads called “Fast Burn Heads”. They flow very well in both intake and exhaust ports (more power). They have smaller combustion chambers (62cc’s) which will raise your compression ratio slightly (more power). Being that the heads are made out of aluminum the engine will be able to tolerate more compression. Typically and engine with aluminum heads can tolerate a higher compression ratio (.5 to .75 more) Example: 9.75 to 1 compared to 9.0 to 1.
The valve springs supplied with the heads will handle up to .520” valve lift. These heads retail for about $610 each. Part#12464928 form Scoggin Dickey Parts Center.
1-800-456-0211
G |
Brian Brackett
Senior Member
Username: kainon
Post Number: 1018
Registered: 03-2009
| | Posted on Saturday, October 31, 2009 - 11:21 pm: |
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If you have friends that work at a dealership or friends with an autoshop.. they can get you a substantial discount.. |
chiefalen
Advanced Member
Username: chiefalen
Post Number: 320
Registered: 03-2008
| | Posted on Sunday, November 01, 2009 - 06:07 am: |
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I ask you to consider whats behind the motor, and can it handle all this power upgrades?
In other words what drive? |
mike weakley
Member
Username: mikey43
Post Number: 10
Registered: 10-2009
| | Posted on Sunday, November 01, 2009 - 08:53 am: |
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chiefalen its a alpha 1 no more then 300hp right? thanks for all the help guys!!! |
Bt Doctur
Senior Member
Username: bt_doctur
Post Number: 1201
Registered: 06-2006
| | Posted on Sunday, November 01, 2009 - 08:58 am: |
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Not unles you want a set of PRO- RT big valve heads
[IMG]http://i57.photobucket.com/albums/g219/BtDoctur/IMG_1480.jpg[/IMG]
[IMG]http://i57.photobucket.com/albums/g219/BtDoctur/IMG_1481.jpg[/IMG] |
Bob Griest
Member
Username: hippie
Post Number: 71
Registered: 04-2009
| | Posted on Sunday, November 01, 2009 - 07:18 pm: |
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An Alpha-1 is not to be reved above 5,000 rpms. It already sounds like you are above the 300 hp max. Bob |
chiefalen
Advanced Member
Username: chiefalen
Post Number: 323
Registered: 03-2008
| | Posted on Sunday, November 01, 2009 - 09:15 pm: |
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they did make a set of hd gears. but for sure not above 350 hp.
Want more power any bravo unit will do bravo 3 maybe the best.
But i got to say with this economy you could probably get the hp and drive you want in a hull maybe 5-7 years old at a better price then trying to change out the motor and drive.
Just my opinion. |
chiefalen
Advanced Member
Username: chiefalen
Post Number: 324
Registered: 03-2008
| | Posted on Monday, November 02, 2009 - 08:58 am: |
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well i found the part number for the hd gear set price i don't know.
1841OA4
But here is the glitch you need different bearings see they are thinner.
I have only seen this one time and was maybe 10-15 years ago saw everything laid out on the table.
Was comparing everything, the gears are alot thicker and regular bearings won't fit.
Now heres another thing there was a very limited edition alpha called a SS, very expensive and limited numbers made. I never saw one.
Hope i am not rambling too mush. |
henry S.
Member
Username: mongo
Post Number: 50
Registered: 07-2008
| | Posted on Monday, November 02, 2009 - 04:03 pm: |
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The SS Alpha was 2.5 inches shorter than the standard drive - raised the X-dimension. Did not work on every boat because on some the prop became too near the surface and did nothing but ventilate, could not get on plane. I don't believe the gears or shafts were larger, just a shorter lower gear case. |
chiefalen
Advanced Member
Username: chiefalen
Post Number: 326
Registered: 03-2008
| | Posted on Monday, November 02, 2009 - 04:25 pm: |
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maybe they had to be installed new and the hole cut for them, maybe thats why they are so rare, maybe they were used in real fast boats, who else needs gears rated for 454's.
How many 350's back then were being built above 260 hp? |
Kghost
Senior Member
Username: kghost
Post Number: 1061
Registered: 07-2008
| | Posted on Monday, November 02, 2009 - 07:49 pm: |
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Lots, in 1986 they had a 32o hp fuel injected 350 rated at 320 hp. In a 18-19 ft checkmate it did 75 miles per hour. Boat was a screamer!!
My suggestion would be to identify what parts are infact in the motor and speak with a local engine builder and see what he recommends. Most likely put in larger valves and good springs and port match the exhaust and intake would be about all you need. It aint going to be a real big gain but enough. |
mike weakley
Member
Username: mikey43
Post Number: 11
Registered: 10-2009
| | Posted on Tuesday, November 03, 2009 - 08:45 pm: |
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ok got the heads off they said some of the valves were not seated right!!!! bad machine work!! |
mike weakley
Member
Username: mikey43
Post Number: 13
Registered: 10-2009
| | Posted on Wednesday, November 04, 2009 - 08:35 pm: |
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what causes valves to suck in 2 on one side and 2 on the other any ideas??? |
Bt Doctur
Senior Member
Username: bt_doctur
Post Number: 1210
Registered: 06-2006
| | Posted on Wednesday, November 04, 2009 - 08:57 pm: |
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If you mean"Tuliping" usually water ingestion |
makomark
Senior Member
Username: makomark
Post Number: 1832
Registered: 09-2008
| | Posted on Wednesday, November 04, 2009 - 09:22 pm: |
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intakes, exhausts, or both? |
chiefalen
Advanced Member
Username: chiefalen
Post Number: 334
Registered: 03-2008
| | Posted on Thursday, November 05, 2009 - 05:54 pm: |
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what metal was the valves made out of?
Check your fuel could be full of water. |
mike weakley
Member
Username: mikey43
Post Number: 14
Registered: 10-2009
| | Posted on Thursday, November 05, 2009 - 08:40 pm: |
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intakes i cant think of the material they told me. i will check the fuel. he ordered 8 new ones. |
mike weakley
Member
Username: mikey43
Post Number: 15
Registered: 10-2009
| | Posted on Thursday, November 05, 2009 - 08:44 pm: |
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yes bt doctur tuliping. |
