small block cam questions
 

so you guys answered my head questions I have a 242ls with twins it has 2-383's in it. has dart iron eagle heads with 202 160 valves so I got the cam out and it isnt a name brand but has 115941 371342 usa stamped on the end and cwc 1539 in the casting between the lobes one site said it was a reproduction lt1 cam I dont know it does have midlift pro 7075 on the roller rockers and some comp cams 7972 7.800 .080 pushrods (thats what it says on sode of pushrod and a stock stlyle aluminum intake made my professional products number 52000. and a stock quadrajet carb. now if this is a stock style cam with a stock style intake and the quadrajet carb this really isnt putting out the power that its capable of right? what kind of power should i expect out of a more or less "stock" 383 with nothing done to it but heads and rockers? then with my given rockers and pushrods what kind of cam would be best for this? im changing the intakes and carbs because i beleive its holding it back. someone please correct me if im wrong. im rebuilding one of the engines and putting a cam on the other engine really isnt a big deal. so i need some experienced guidance. the boat i had before this one was the exact same boat with 2 stock 350's turning 23p cleavers and it would run 65 all day long so this one has 25p cleavers but without supporting additional mods to these engines im worried its too much prop for it

I ran comp xtreme marine 262 cams in my 26 nova. I loved the sound and the performance, they are mild mannered with noticable sound and great torque. My engines were 350s with world products iron heads, performer intakes with quads.

What size carbs and what kind of gains did you get

My 383 , Trick flo heads , Edelbrock rpm air gap intake-port matched , Dean Nickerson carb-mechanical secondaries , CMI E-top headers-dry tails so as not to restrict cam choice , fully balanced rotating assembly . For your cams , in a word , Call Bob Madara !!!! 585-654-8583

If you truly have LT-1 cams in 383's stick with it. If the intakes will take a square pattern Holley...get a pair of 750 Double Pumpers and you should be good to go. If not get the intakes that will receive the Holley's like the Edelbrock Performer Air Slot.

see i dont know if they are lt1 cams thats just what someone suggested to someone on another site that the guy had a cam numbered the same as mine but I just decided Im gonna make this little boat scream since the foundation is there I might as well. I know at 65 my old one was dancing on top the water, so I want to make this one silly fast (not fast for some of you) so Im for sure doing intakes and carbs. will the stock fuel pumps keep up or should those be changed too? what realistic conservitive numbers can i expect hp wise? everyone says 100hp to get 10mph so by adding 200 i should gain 20? I cant imagine going 85mph in this it would be neat but I dont see it.

You could use the Chevy 383 crate motor for a base line, cam specs, intake and carb. What type exhaust are you running ? will it support what you're trying to gain. The faster you go the more HP it takes to go faster.

looks like factory stuff but new even the inside doesnt look like there is too much time on them the engines are only 2 seasons old so i was hoping the engine broke from over camming it and sucking in water but since i guess its stock style that wasnt the problem. I would love to put headers on but they are not the slightest bit cheap x2 so its on my list but not at the top

I changed all fuel lines to 1/2 " and ran an Edelbrock race pump . This package ran awesome and made little kids cry when i fired up at the dock ! Marine engines have different fuel requirements than cars so be careful what you buy . Do it right the FIRST time .

I still have my CMI's stored in the garage and would part with for 1/2 the price of new and would make every effort to make buyer comfortable their NOT JUNK .

so you have 2 sets or just one

Sorry , just one set . Fully polished , dry tails .

sorry I dont know all the terms dry tails? my current setup exits below swim platform im interested but im not sure how universal they are

Dry tailpipes , cooling water never mixes with the exhaust gasses . Cooling water exits via outer tail pipe water jacket and exhaust via center pipe . Absolutely no chance of reversion . Tails exit thru the transom and extend about 6 or 7 inches aft . On the boat they were on also under the platform . You can run a hotter cam for maximum power with dry tails . This is also much more expensive exhaust system . To me it was worth every penny . I hope this helps you .

OK...let's say your 383's are making 400 horse power...you theoretically have 800 horsepower in the water in a boat that weighs around 5500 lbs with a full fuel load and driver. You have plenty of power...you are limited by the drives and the drag of the hull. A fast tech step hull with that power will get to 80 MPH and beyond but a conventional V bottom, Alpha drives with the traditional "Formula Hook" might not get there with 1000 horsepower. All you will end up doing is chine walking all over the place and possibly flipping the boat.

You are at the point that you need to start looking at custom drive nose cones and shorter X dimensions to get past 70~75 with a 242 LS.

I have a similar situation with similar power. I figure 75 is the most I will ever see from mine and I am resolved to be happy with that as well as the ability to cruise at 50~55 with out strain all day.:evilb:

Please don't forget to call Bob Madara for cam help . One of his first questions will be , wet or dry exhaust , makes a huge diff in cam selection . By the way , he is the best there is as far as marine valve trains period .. this is not just my opinion but just about everyone here at O.S.O.

Bob is the king of valvetrain.