ok let's see how im doing have twin 350 mags 1991 pushing 270hp. doing some research im looking at world heads s/r torquer 2.02 valves 2.020x1.600 the book says i will get another thirty hp im running emi exhaust w/stainleess risers.also changing to comp cam model#12-210-2 rpm 2200-5200 intake and exhaust @.050 is 218 valve lift .454.going to a new crank and rod kit with flat top pistons.does this sound like i will increase my hp if yes to approx how much.a friend of mine owns a machine shop im only paying for parts.also the engine will be balanced.? will i get reversion or am i safe.

For a boat you need torque. For torque the easiest way is CID. I would look at prepping 2 x 383 CID. These engine are capable of legit 400HP/475#/ft of torque and still be reliable. If you did this I would recommend going with sportman heads.

Chris

Stroke It Baby!!!
A 383 stroker kit is the way to go.
I built one for my single engine boat, and the difference is incredible! Tons of torque. I attached a breakdown of the parts I used. If you have any questions, just email me.

Paul

The attachment didn't work, so I just copied and pasted it here:

1. Chevy Four Bolt Main Truck Block Bored +.030”
2. Scat 383 Stroker Kit # 1-383IPS Consisting of:
· Scat 9000 series stroker crank
· Scat Forged 6” “I” Beam rods
· SRP Forged Dished Pistons +.030” # 138103 16cc Dish
3. Total Seal Gapless File-to-Fit Rings
4. Comp Cams Xtreme Marine cam # 12-236-3 (XM262-H)
5. Comp Cams Lifters # 812-16
6. Comp cams Valve Springs # 981-16
7. Comp Cams Magnum Roller Tip Rockers 1.5:1 #1417-16
8. Cloyes True Roller Timing Chain #
9. Clevite F-77 Tri-Metal Bearings (std.) Cam, Rod, Main
10. Melling High Pressure Oil Pump # M55A
11. GM Extended Oil Pickup for 5Qt. Pan.
12. GM Performance Parts Cyl. Heads #10125377
13. GM Performance Parts Intake Manifold #14097494

liberator thank you.how much for the parts no labor?

For a idea over the past 2 years I have ran two 383's and building another one.

1. 383

2 bolt block
eagle forged 3.75 crank
eagle h Beam "3D" 6.00" rods
SRP dished pistons. 9.9:1
vortec heads machined for screw in studs, guideplates
222/230 .542/.563 roller cam
All crane valvetrain
air gap intake
750 holley
EMI exhaust
around 400hp at 5200 rpm

last year I ran..

383

4 bolt block
same crank
same rods
JE flattops pistons ( 10.8:1) w/110 octane
AFR 210 aluminum heads 2.08/1.6 valves
234/242 .574/.595 roller cam
All crane valvetrain
Edelbrock victor jr intake port matched
750 holley
EMi exhaust
around 500 hp at 5500 rpm

now i am building this

383
same block
same crank
same rods
JE pistons ( 12.7:1) w/110 octane
same heads
250/258 .598/.598 lift solid roller cam
edelbrock victor jr intake port matched
800 or 850 holley
EMI exhaust
should be in the neighborhood of 570 hp

you don't even want to know how much this cost

im still wating for answer or comment on what i want.i appreiate information on the 383 but that's not what i want.

I have 1996 5.7s that were just rebuilt stock. I have built a few 383 stroker motors for cars in the past and would do the same but hate to tear apart or replace brand new rebuilds. I was thinking about just replacing cam, ignition, intake and exhast and then adding small B&M blowers. What are the pros and cons to that?

Why new crank and rods? Do those motors have flattops already or are they dished?

Reversion... you see the cams I ran on my setups. i have never had reversion. With that small of cam you should not have any reversion, esspecially it is a little safer with the EMI exhaust you are runnin.

Are your exhaust thru the transom or thru the drive?

sonic28
The 12-210-2 cam you are looking at is a single pattern cam ground on 110* LSA. The Torquer heads have a good exhaust port with an I/E ratio of approx 78% but you would do better with a dual pattern with about a 4* split on a 112* LSA. The wider sep will provide some insurance against reversion. Depending on the displacement and compression ratio you go with(350/383) I can give you some duration numbers on shelf and custom marine grinds. Because your block is already set up for roller have you considered those options?
Bob