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Discussion Starter · #1 ·
I'm a relative engine idiot so bear with me please...

The rockers on the 409 my father in law is helping me build are worn past what he considers acceptable. So he said I should upgrade and get roller rockers...

I've read a lot about aluminum fatiguing and this is just a ski boat, so lower maintenance and longer life are desirable. SS and chromolly steel seem to be the better choices.

It seems to me that needle bearings would reduce friction, but I understand the possibility of them failing and sending alot of small pieces of hardened steel into the motor.

I'm told that 1:7 will work on the 409, but stock is 1:75. There are a few 1:75 Chevy available, but also some 1:72 and 1:75 Fords...will the fords work, should I stick with the 1:7 BBC, am I overthinking this?

If I change out the cam and go with a roller cam later can I keep using the same roller rockers?

I'm looking at Harland Sharp (based on reputation), Comp Pro magnum, and Crower. And comments or other recommendations?

Thanks for your expertise!
 

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Some guy
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I don't know that I would worry about aluminum fatigue in a ski boat. I ran Isky aluminum in my turbocharged ski race engine for years with no failure, however Isky is considered to be one of the better aluminum rockers.

You might consider Scorpions for your engine. I have them on a dirt modified sbc engine that runs 7000 rpm, and have put them on a number of marine engines with no sign of problems yet.
 

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Any Ford parts that you can add to your engines will only help performance... :)

Actually I think that I have BBC rockers on my 429 CJ... :cool:

Just be CERTAIN to check your rocker geometry / pushrod length and spring bind durring test assembly if your using something other than stock rockers/cam/pushrods... You can buy OR make an adjustable pushrod to determine the perfect pushrod length...

She so fine, my 409... :)devil
 

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Roller Rockers vs Expense

Unless you are ABSOLUTELY SURE you will later upgrade to a roller shaft, save your money and spend it somewhere else. If you are building a ski/play engine,the extra expense will be best spent on gaskets or fuel or some other expenses that will come up shortly.Just my opinion...
 

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The fatigue life of Aluminum rockers depends a huge ammount on the springs run, the lift against them, and the RPM the engine spins.

On a stock or mildly lifted engine, even cheaper Al. rockers may well last a long time, premiums may live nearly forever.

Some serious engines have even broken the Comp Pro Magnum steel ones, so nothing is absolutely indestructable.

That said, you have gotten sound advice above IMO, and, are likely overthinking the ratio availability a good deal.
I understand wanting "everything you can get", but, for a working ski-boat engine, IMO, it is not particularly important to split the hair of 1.7:1 vs 1.72:1 vs 1.75:1.
Different story where racing is about squeezing out every last 1/4HP you can find.

I managed a lucky find when I went roller. I was contemplating dropping close to $300 on a set of Pro Magnums, when a friend of mine informed me he had a set of Comp Hy-Tech's (their premium Stainless Steel roller rocker), used, for a very good price (a bit over 1/4 new).
Bought, sent to Comp for factory rebuild, paid $120 for that, and had new H.T.'s for less than new Pro Mags, about 3/5 of new H.T.'s.

I'm running a pretty aggressive hyd, but aggressive for a Hyd Flat Tappet, so my Hy-Techs may well get willed to the next kid to inherit Lowrider. ;)


Now, I did have to buy longer studs, and had to buy Comp's locknuts too, but, those would have had to be bought anyhow in the changeover.
 

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I got the Scorpion 1.75s for my 8.1L from SDPC. They are also listed for 348-409, I believe. Unless the 409 takes 3/8" studs instead of 7/16". Anyway, the 1.75 Scorpion rockers are STOUT. If you have stock valve covers, they won't fit for sure. Most rollers won't anyway. So, keep that in mind with your swap.
 

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When Crane was in business they offered a direct replacement for the 348-409 rocker arms. When I was in the market for some replacements for my Bel-Air I found out the stock type were of inferior quality and subject to premature failure, thus I went with the roller rockers, and clearence inside stock 409 valve covers is not a problem. I'm sure you need rockers for 3/8 studs though, unless yours have been upgraded.
 

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I'm sure you need rockers for 3/8 studs though, unless yours have been upgraded.
That's what I was thinking. I seemed to remember that Wmotors were like a cross between small and big blocks. Big block ratio with small block stud.
 

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Discussion Starter · #11 ·
I have Edelbrock cast valve covers so clearance should be fine.

I agree that upgrading the studs is important...I was worried just about the press in part, I'll take an extra 1/16" anywhere I can.

I thank everyone for the money saving thoughts, but if if it was a smart investment(or if I were a smart investor)...it wouldn't be a boat and it sure wouldn't be a 409. I'll feel better hopefully doing things 7/8 right the first time and running it.
 

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roller rockers

Being a 409 guy from years back I think your engine choice is just great and in a Lebel even better.
What heads are on your 09? All the hi-perf/large port heads had pinned 3/8 studs from the factory and would be ok on most hyd flat tappet cam apps. Any good quality roller rocker should work fine with the stock studs.
If you plan on getting more aggressive I would switch to 7/16 studs for sure. There is also a few people that make stud girdles or shaft rockers that fit these heads if you decide to step up to a solid roller and really make some power.

Later,
Fred
 

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They are 690s, but I think the 7/16 taller screw in stud would be the way to go.
BINGO

We have a winner, that would be the smart move. One thing you need to be aware of is the need to seal under the new stud, since the press ins go directly to a water jacket, and the pin hole will cause a leak. Ask me how I know. If you need more info on this procedure feel free to contact me.
 

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BINGO

We have a winner, that would be the smart move. One thing you need to be aware of is the need to seal under the new stud, since the press ins go directly to a water jacket, and the pin hole will cause a leak. Ask me how I know. If you need more info on this procedure feel free to contact me.
I had my 690's threaded into the heads. No water issues that way.

Motor vehicle Vehicle Automotive exterior Car Red
 

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I had my 690's threaded into the heads. No water issues that way.

View attachment 57606
STRANGE cause I had the same deal and when I replaced my pinned studs with screw ins I had water leakage at the pin holes. Perhaps our heads were finish machined at different locations, cause my stud bosses were drilled all the way into the water jackets.

So when Lebel409 does his heads he should verify if his are drilled through or not.
 
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