mike tkach

iTrader: (3)

i dont care who is doing the build,when you stick a crank with a stroke longer than 4.250 in a 9.8 deck block it will not be a long lasting engine.yes it can be done but in a marine application it is not recomended.a good builder will not do it because he knows it is not a good idea and can come back to haunt him.the guys as you put it that build big motors know better than to build incorrectly.

bcfountain

I jus had this conversation this weekend at a pokerrun with a engine builder.it can be done.but is not a good idea.

Rookie

iTrader: (4)

Corrected it for you.

4.250" is common in a short deck.

Rookie

iTrader: (4)

I was not saying it was good nor bad to build a 4.375" stroker 9.8" deck engine. I threw out the idea a few years ago to a few respected marine engine builders and they all said it was not worth the hassle. I have read on drag racing forums about how they like them is why proposed the question. I was only looking for information on rods and pin height to educate myself. This forum is for sharing knowledge and educating others.
Thanks

682gold

iTrader: (3)

Through talking with some engine builders who are familiar with marine engines I have found a 555 is about the same price as a 540.

Black Baja

iTrader: (2)

I understand what you are saying and agree to a point is a 4.375 crank in a short deck the best fit for longevity? No, it's not but neither is a 4.25. There is always compromises when building motors. Alot of guys would rather build a 4.25 motor because most of the time the is no extra work that needs to be done to the block. Someone who has built 40-50 of these motors is gonna have an advantage over someone who has only built 1 or 2. With experience comes knowledge and know what the proper rod length ring stack and piston skirt design will make a big difference in how long the motor will live. Does it mean its going to last forever? No, a marine engine will bring out any little flaw a motor has rather quickly put a blower on top or side of it and its going to bring it out that much faster... It all boils down to what your trying to do and how much you can afford.

mike tkach

iTrader: (3)

thanks but my statement did not need correcting,there is a reason 4.250 is common and 4.375 is not but if someone wants to build a 4.375 stroke engine in a short deck more power to him,i wont do it but what do i know!

MILD THUNDER

iTrader: (3)

I want a tall deck 396 with a 3.76 stroke and some peanut port heads. My max RPM I would like to spin is 4000. I have a 2 barrel rochester carb for it. Its gonna be 11.5:1 compression with an RV cam. I plan to run it on 87 octane with projected tip plugs, cast pistons, 210* water stat, and 39* of locked timing. Shooting for an air fuel ratio around 15:1, for good MPG. I am hoping for 650hp at 4000rpm. I really need the midrange cruise

Black Baja

iTrader: (2)

Y not just use a 4 cylinder?

Rookie

iTrader: (4)

Woops, sorry I misread your post. I looked past "stroke longer than 4.250"
My apologies