350 magnum mods ?

[270 laser]

I have a 1993Powerquest 270laser twin 350mags,nosecones,alpha gen2s. the boat ran 65mph stock. I added stern jacks, it now runs 70 mph on gps with 24 pitch laser2 props at 5100rpm. im looking for head,cam,intake or blower recommendations. I want to use the stock short blocks and preferrably not remove the engines(I have enough room in boat to change cams. the motors only have 180 hrs. Thanks.

[The Raven]

Hi your Boat sound Nice. 70 mph. Is very respectiable with 2 small blocks pushing a 27 foot boat. Must be light .
I have a 1984 242 Formula [5200 lbs] with 2 worked small bocks. Getting 68 to 70 when set up to run top end. 14 1/2 x 24 + [ re worked ] 3 blade clever props. On yours I would try exhaust system { alum. or light weight in Fresh water only}. If carbed. Try a Set of heads like dart 2, with steel seats and SS valves, Roller rockers , High rise Intake, and a Larger Holly carb. I run 650s, dual feed double pumpers.
Good plug wires and coils. I use Jaccobs. there great. For the cam be carefull do some research. Try to contact Merc. for advice on the specs. Boat and truck cams are simillar.
You will have to have the Props RE worked , add more pitch, or borrow a set .
Don't get too NUTS with it if the bottom end has hard hours on it. And You just might get it too quick for the hull design, Chin walk will scare the hell out of most people.
Keep in touch, I'll snoop around and see about the cams.

[270 laser]

Thanks for the reply, I didnt think anyone cared about small blocks. Do you think aftermarket exhausts are necessary. Ive heard mixed reviews about them on stock engines, especially small blocks(no big gains) Keep in mind that I have the same exhausts that are used on Scorpion 377s. I dont want to go over 400HP. I bought a set of vortec heads, I just ordered Inconel exhaust valves & bigger springs. Let me know what you think for the cam, intake & carb. My boat weighs 7920lbs. with full tank& trailer on a truck scale. The boat is rated at 5100lbs. from powerquest. The stern jacks were a huge gain on this boat, 7-8 mph.

[The Raven]

Sounds like you got a good start. I would skip the exhaust, there way over priced for what you get in return. I have Merc. 4" and they are just fine.
Your engines are different thean Mine. I have the old style blocks. So my manifolds won't work. But If you can get your hands on a Chevy Hi performance catalog They list a TON of Hot items.
I like the Holly carbs myself. 650s seem to be ok, you won't need 850s. but you might want to ask for other opinions.
My best advice for cams is try to contact Merc. High performance by phone. I got all my REALISTIC info from the guys . There more than willing to help. It might take a few tries to get the right number. Try to get a Merc. High performance catalog. the number I think is listed there. You have to be carefull with the cams, to big and they can suck in water from the exhaust. make sure your Fuel pumps are up to snuff.
Have a look at the hull bottom at the transom, see if you have any HOOK. If so it will drive the bow down and you lose speed.
Keep me informed. I will see if I can get you the Phone number.
PS. I also used a Larger Flame arrestor, Stock Mercs. For a BIG block.

[Hotcrusader76]

Originally posted by The Raven:
Sounds like you got a good start. I would skip the exhaust, there way over priced for what you get in return. I have Merc. 4" and they are just fine.
Your engines are different thean Mine. I have the old style blocks. So my manifolds won't work. But If you can get your hands on a Chevy Hi performance catalog They list a TON of Hot items.
I like the Holly carbs myself. 650s seem to be ok, you won't need 850s. but you might want to ask for other opinions.
My best advice for cams is try to contact Merc. High performance by phone. I got all my REALISTIC info from the guys . There more than willing to help. It might take a few tries to get the right number. Try to get a Merc. High performance catalog. the number I think is listed there. You have to be carefull with the cams, to big and they can suck in water from the exhaust. make sure your Fuel pumps are up to snuff.
Have a look at the hull bottom at the transom, see if you have any HOOK. If so it will drive the bow down and you lose speed.
Keep me informed. I will see if I can get you the Phone number.
PS. I also used a Larger Flame arrestor, Stock Mercs. For a BIG block.
Your advice is very valid. Stick with the 650cfm Holley. Mech vs. Vacuum secondaries are up pure choice. But the VS would be better choice in my eyes. Just make sure and convert the metering style from 4160 to 4150.
If you need some more help, contact me.
Thanks
Ty Lofstrom
TPC Racing
sales@tpcracing.com

[gnarley]

Originally posted by 270 laser:
The stern jacks were a huge gain on this boat, 7-8 mph.
270 Laser, What are stern jacks? Are they the same as trim tabs??

[Chestah Cheetah]

Originally posted by gnarley:
What are stern jacks?
It's an outdrive spacer. Has nothing to do with trim tabs.

[kevnmcd]

Originally posted by gnarley:
270 Laser, What are stern jacks? Are they the same as trim tabs??
gnarley-they are made by Land & Sea...here is a pic of them.
http://www.dynomite.com/images/marin..._color_600.gif

[gnarley]

Got it thanks. Now I do remember seeing them before.

[BOFH]

Thje smal block is a wonderfull motor. I would have a 383 over a 454 any day! :-)
As to quick mods... Your exhaust is OK, and getting headers alone would be a disapointment. A cam would be nice. A reworked carb can show big gains. Also, ratio rockers can be a big gainer! If you do carb cam and rockers, then a header can be worthwhile...