Drinkin fountian

Started taking apart/inspecting the 502 (its a zz502 w/ the 500HP cam in it and 320 RHS alum. heads) out of the boat I bought this last fall. Only bad things so far is that (1)... 2 cylinders are burning a touch (not excessive) of oil but wall look good and stock bore. and (2) There was a brase distr. gear on it and it was really worn thin. So far Im pleased and still am planning on putting a 10-71 and re-camming it. THE MAIN QUESTION IS... I have always planned on replacing the rod bolt with some new ARP, BUT I've been reading alot on forums about upgrading wristpins. What kind of pins do you suggest? I would be all for that too just for the extra security, but I don't want to upset the factory ext. balance. I know that internal bal. is better anyways but Im keeping this build on a budget and dont plan on running this motor for maybe 2 seasons. How much of a wieght differance would be tolerable and still be ok? AND I haven't checked bearing clearances yet but would like to run 6200 rpms (if I need too! Dont plan on switching props. Motor peaked 51-5200 rpms before.) How high do you think I can safely go? (assuming clearences check out ok?)

mr3dman

read your post a cpl of times and here is my .02.... You are dropping the time and money to throw a 10-71 on it and I'm assuming you are upgrading the fuel delivery, cooling, ignition, etc to make this run right. Also you want to spin the engine another 1k rpm's and hit 6k-6100 rpm to boot. I'm guessing you are replacing the rings and bearings while the engine is apart, at the same time re camming and probably lifters and springs to be safe as well right? You also wan't to replace the wrist pins with arp pins to be "safe". The easiest route is to weigh the old pins vs the new pins and call your local builder and see if the weight diff is ok. Your best route is to spend a few bucks more than you already are and just get the assembly balanced since it is all out of the engine anyway. You are going to be spending alot to do this project, what is a few more bucks to balance and buy a neutral flywheel? 2 seasons on a blower setup, depending on hours, is usually go through time anyway. Just food for thought

MILD THUNDER

iTrader: (3)

What I personally would do, is strip the shortblock. Your crank is a good piece. Having the machine shop cut in a extra keyway is a good idea. I would forget about recondition the GM Rods. For the cost, your better off with a set of Scat, eagle, or manley H beam rods, with ARP 2000 Capscrew bolts. Much better rod than the GM rods. Get a set of blower specific JE pistons, total seal rings, and build yourself a solid shortblock. The pins that come with the JE blower pistons are .180 wall, and will be fine for what your doing.

Then get yourself a nice blower grind, some morel lifters, a fresh valve job on the heads. You'll want to use inconel exhaust valves and a good severe duty intake valve. A quality set of valve springs, the isky tool room series are very nice, and so are the slightly cheaper isky sp endurance series. Use some Cometic or Felpro MLS headgaskets. (Be sure to tell machine shop doing the work to provide the proper RA finish on the deck and heads for that).

Basically, your now building a blower specific engine. And if all the proper steps are taken, You can easily have a 800-850HP engine that will last many years. If you do the basic slap some rings in it now, some bearings, change the cam, and bolt the blower on, you might be ok for a while. However, ''might'' is the key word.

Drinkin fountian

I have a 540 NA motor that has all the good stuff and puts out 900+ hp, just sitting in my garage not being used. Its not set up for marine use though, but if I LIKE the 10-71 on a mild 502 then I will be going for an all out build on the 540 motor rebuild, PLUS I need the extra time to up grade from the Bravo 1! Then, I'll be changing props. Im not looking for this 502 to be putting out 800 HP, just a little bit more to help my pig boat to get up on plain easier and at same time use this motor to learn and get a feel for a supercharger. SURE, I wish I had the money to go striaght to it and do it all at once and right the 1st time, BUT, I would also like to sell my boat and have a brand new Nor-Tech or DCB built for me too! LOL

MILD THUNDER

iTrader: (3)

Then just hone it, re-ring it and go for it. I wouldnt worry about changing the stock piston pins. Use a nice blower cam, fresh set of valve springs, and keep the boost to about 4-5lbs. With a 502, RHS alum heads, probably close to 9:1 compression, you'll be making about 800hp with a decent blower cam on low boost.

The drive wont last long on a single 29 with 800HP unless its heavily modified.

Drinkin fountian

Thats kinda what I was thinking. I am looking for someone local here to go thru my bravo just to see if its sound to start with. I don't put many hrs per season on the boat to begin with, nor hard hrs. So Im hoping it will last a couple yrs at least?! Bye the way, congrats on your new build!! Read your dyno forum

MILD THUNDER

iTrader: (3)

Thanks...nothin fancy just some old school stuff !

rchevelle71

iTrader: (1)

Since when is a 29 fountain a pig?

Drinkin fountian

Well, I never felt that way until I took 4 friends with me to the Bud Shootout (LOTO) and couldn't get boat on plain without having someone get up in the cuddy!! We did have some big coolers full of beverages too, but still!! That was embarassing!!

Mr Gadgets

Sorry, but 10-71 and Bravo, just dont mix!! Be very careful with available torque if you go this route.