Help me build a 383 stroker
 

Right now I have a 350 mag alpha combo. The motor runs great and as far as I know has never been touched. Due to some bilge work needed the motor has to come out, so I figure this is prime time to do a little wrenchin'

It's a 92 350 mag. So I think that means it is a 4 bolt block. Basically I need to know everything. What rotating assy should I use. What heads, cam, intake and carb should I use. I have been digging through the forums, and the recomendations are all over the map. Even though it may be counterproductive right now the factory exhaust will have to remain until at least next year.

Thanks for any advise you may have.

Scat or Eagle crank & rods , we used scat. We also used World Sportsman II heads, Bullet Racing Cams # CHS 288/296-10HR Int 223 Exh 530 @.050 Lift Int .530 Exh .548 with a 110 centerline this cam is a HYD roller. Edelbrock Performer RPM Intake and Edelbrock 750 cfm marine . They made 425 hp @ 5250 on the Dyno .You can make more with AFR heads and Demon carb but it will cost .:drink:

Lets start with the rotating assembly. What should I look for, other than forged pistons?

Certainly on the right track here. Although I would go with Dart Pro 1's and a Holley 750cfm. Either way, they'll both work really well. I would put compression around 9.5:1 for a non sc'd application. Very safe, will run on 87 octane. Get in the 10's and you'll be pushing the envelope.

Take a look at CNC MOTORSPORTS ( www.cnc-motorsports.com ) they helped me out . :ernaehrung004:

what are the advantages/ disadvantages to the 5.7 or 6 inch rods? Are you running a cast crank?

We used 5.7 rods and the Scat ser. 9000 cast crank -12cc pistons.

What type of rocker set up are you running?

We used Comp Pro Magnum Roller Rockers 1.52 7/16 stud . The lifters and push rods were from Bullet Cams .

Thanks for the quick responses. I am just starting the search, and don't really know where to look. I am trying to get a ballpark price to make a decision. The thing runs like a top now, but someone else is paying for the removal, and reinstallation of the motor. I would like to take advantage of the situation, but I don't know if it is worth it opening that motor. You know, if it isn't broke, don't fix it....

Sell what you have and buy what you want.:ernaehrung004: You need to know how much Hp you want to make then you know what to buy.

Well, 4800 puts me at 51gps with a 1.5 ratio drive and an 19p prop. If I can't break 60 then I would rather stay where I am.

It should take around 200 hp to pick up 10mph if that helps .

and thats all dependant on your hull....some you could throw 500 at and not pick up 5 mph ! Rob

I upgraded a 20ft boat two winter ago that before/after was 55mph/68mph in same exact conditions/fuel load. Prop was maximized in before condition. Not quiet sure in after yet - still working on that.

Before: '91 5.7/260hp Mag that had better carb, arrestor, intake, exhaust than stock. Was running 3-4mph faster with these upgrades vs stock.

After: untouched shortblock from above - new heads, intake, cam. Same carb, flame arrestor, exhaust, and TbIV ignition.

Note: Would not go over 65-66 (all props tried would blow out right at 65-66) until I put a nosecone on the 1.5 Alpha drive. Bang - 68 with no prop blowout.

So, how do I know if I should open up the bottom end? It runs strong and burns almost no oil. Should I just do some top end goodies and let the bottom stay??

piece of mind... dont know about you, but I would hate to do a lot of top end work, then blow the rings thru the pan.

Thats kind of what I was originally thinking. Do the bottom now because it will be out of the boat. Ok, so... Lets make a list. Scat or eagle crank, cast it ok. Connecting rods. 5.7 or 6? Pistons, forged. Heads, performer rpm intake, 750cfm carb. What should I look for in a cam?

leave the engine alone and start with a different block.

98 pick up motor turned into 383 full scat parts eagle crank howard brown cam 530 lift not sure of duration vortech heads manley valves double spring valves com roller lifters apox 450 horse 22ft scarab alpha outdrive 72 gps no more than 30 degrees timing will melt already found that out engine builder said 650 demon or 650 quick fuel nothing bigger to much fuel if u go bigger hope this helps