Marinette Boat Forum

Well I am considering Atlantic Marine Store long blocks, either the 318 or 360 for the same price. They have a two year warranty. I have sent them a long list of questions. So I am still pondering this option. Do not know the torque rating yet. The Velvet Drive transmissions c-72's are rated at 495 ft lbs. Of torque in our boat so they will handle it. The props will probably require a more agreesive pitch or new ones. The 318 stroker they offer has 9 to 1 compression and it uses the cam from a 360. There is no core charge or exchange required. I would also consider a different valve tappet arrangement.

Michigan motorz has a mercruiser 383 stroker 340 hp rebuilt 350 block carbureted with lots of nice features but they cost $19,000 bucks with a three year warranty. Our transmissions would work and they do have a reverse rotating motor.

Now you guys having to talk about !

Unless that motor is going in a Go Fast boat, you'd be far better off with a stock 360. Torque (not hp) is what makes the difference between an economical cruising motor, not one that has to have the snots reved out of it to maintain plane. (My old 32 footer with 360s would hold plane down to 2,000 rpm with a full load--and after making a full lock 360 degree turn! That's low speed torque.) The 360s--with their small ports and valves--is ideal for a cruiser.

Jeff

THanks Jeff! Totally understand we want torque at lower rpm not some high revving engine.

Atlantic Marine Store in Hialeh,Fl. Told me they do not recommend the stroker motors for marine use. So the 318'!s will be rebuilt to as close to stock as possible. May upgrade the valve train tappets.

9:-1 compression.... would require nothing less than premium 94 + fuel... Not easy to find and at marine prices pricey!

I might be wrong but I think our stock 318's are around 8:1 Jeff would know for sure.

My 29 with old 318's and 14X11 props will hold plane at 2,200 with full load.

Merry Xmas and Seasons Greetings to all !

I just checked the manual for the240hp version of the 318 (circa 1987-88) and it shows compression at 9:1. Some other HP ratings are at 8.5:1

Correct ! 1987 318's are 9 to 1 compression.. our plan to disassemble and make decisions based on what we find. Cannot wait to have a clean bilge! Yes, our 32 SFB will plane at aprox. 2200 to 2500rpm. We have 1.52 to 1 72 c velvet drives with 15 x 16 props if my memory holds true. Wot was 4,000 rpm at 25 mph. She got to 27mph before we loaded up with stuff and bigger batteries that weigh 400 lbs.we got real tired of killing a standard size car battery as our house battery in a weekend.

Okay guys,against all this talk my 318's are 390 cu.in. stroker motors with 350 h.p. preliminary testing at 4300rpm she was running 33mph. No generator installed during test. Red line is 5800 rpm. She needs more fuel so we are installing Edlebrock 750's. Test putt for us on the Tn. RIVER is May 6,7,8. One year warranty. She planned at 2300rpm.

KEEP ME POSTED ON THIS - Atlantic Marine is down the street and I'm still figuring out why my single 318 is dirt slow with good compression and a squeaky clean bottom.

If I can't work it out this spring, I'm repowering in the fall. Its a couple grand more but I only have one engine and need as much there as possible. If I go stroker, I can keep all the upgraded manifolds & ignition & fuel system upgrades I did.

If I ditch to a 440, I'm back at square 1. Not giving up yet but my eye is on the 330hp stroker package.

You speed freak, you! Love to hear how those monsters worked out.

Jeff